public interface AmazonDynamoDB
Overview
This is the Amazon DynamoDB API Reference. This guide provides descriptions and samples of the low-level DynamoDB API. For information about DynamoDB application development, see the Amazon DynamoDB Developer Guide .
Instead of making the requests to the low-level DynamoDB API directly from your application, we recommend that you use the AWS Software Development Kits (SDKs). The easy-to-use libraries in the AWS SDKs make it unnecessary to call the low-level DynamoDB API directly from your application. The libraries take care of request authentication, serialization, and connection management. For more information, see Using the AWS SDKs with DynamoDB in the Amazon DynamoDB Developer Guide .
If you decide to code against the low-level DynamoDB API directly, you will need to write the necessary code to authenticate your requests. For more information on signing your requests, see Using the DynamoDB API in the Amazon DynamoDB Developer Guide .
The following are short descriptions of each low-level API action, organized by function.
Managing Tables
CreateTable - Creates a table with user-specified provisioned throughput settings. You must designate one attribute as the hash primary key for the table; you can optionally designate a second attribute as the range primary key. DynamoDB creates indexes on these key attributes for fast data access. Optionally, you can create one or more secondary indexes, which provide fast data access using non-key attributes.
DescribeTable - Returns metadata for a table, such as table size, status, and index information.
UpdateTable - Modifies the provisioned throughput settings for a table. Optionally, you can modify the provisioned throughput settings for global secondary indexes on the table.
ListTables - Returns a list of all tables associated with the current AWS account and endpoint.
DeleteTable - Deletes a table and all of its indexes.
For conceptual information about managing tables, see Working with Tables in the Amazon DynamoDB Developer Guide .
Reading Data
GetItem - Returns a set of attributes for the item that has a given primary key. By default, GetItem performs an eventually consistent read; however, applications can request a strongly consistent read instead.
BatchGetItem - Performs multiple GetItem requests for data items using their primary keys, from one table or multiple tables. The response from BatchGetItem has a size limit of 16 MB and returns a maximum of 100 items. Both eventually consistent and strongly consistent reads can be used.
Query - Returns one or more items from a table or a secondary index. You must provide a specific hash key value. You can narrow the scope of the query using comparison operators against a range key value, or on the index key. Query supports either eventual or strong consistency. A single response has a size limit of 1 MB.
Scan - Reads every item in a table; the result set is eventually consistent. You can limit the number of items returned by filtering the data attributes, using conditional expressions. Scan can be used to enable ad-hoc querying of a table against non-key attributes; however, since this is a full table scan without using an index, Scan should not be used for any application query use case that requires predictable performance.
For conceptual information about reading data, see Working with Items and Query and Scan Operations in the Amazon DynamoDB Developer Guide .
Modifying Data
PutItem - Creates a new item, or replaces an existing item with a new item (including all the attributes). By default, if an item in the table already exists with the same primary key, the new item completely replaces the existing item. You can use conditional operators to replace an item only if its attribute values match certain conditions, or to insert a new item only if that item doesn't already exist.
UpdateItem - Modifies the attributes of an existing item. You can also use conditional operators to perform an update only if the item's attribute values match certain conditions.
DeleteItem - Deletes an item in a table by primary key. You can use conditional operators to perform a delete an item only if the item's attribute values match certain conditions.
BatchWriteItem - Performs multiple PutItem and DeleteItem requests across multiple tables in a single request. A failure of any request(s) in the batch will not cause the entire BatchWriteItem operation to fail. Supports batches of up to 25 items to put or delete, with a maximum total request size of 16 MB.
For conceptual information about modifying data, see Working with Items and Query and Scan Operations in the Amazon DynamoDB Developer Guide .
| Modifier and Type | Method and Description |
|---|---|
BatchGetItemResult |
batchGetItem(BatchGetItemRequest batchGetItemRequest)
The BatchGetItem operation returns the attributes of one or
more items from one or more tables.
|
BatchGetItemResult |
batchGetItem(Map<String,KeysAndAttributes> requestItems)
The BatchGetItem operation returns the attributes of one or
more items from one or more tables.
|
BatchGetItemResult |
batchGetItem(Map<String,KeysAndAttributes> requestItems,
String returnConsumedCapacity)
The BatchGetItem operation returns the attributes of one or
more items from one or more tables.
|
BatchWriteItemResult |
batchWriteItem(BatchWriteItemRequest batchWriteItemRequest)
The BatchWriteItem operation puts or deletes multiple items in
one or more tables.
|
BatchWriteItemResult |
batchWriteItem(Map<String,List<WriteRequest>> requestItems)
The BatchWriteItem operation puts or deletes multiple items in
one or more tables.
|
CreateTableResult |
createTable(CreateTableRequest createTableRequest)
The CreateTable operation adds a new table to your account.
|
CreateTableResult |
createTable(List<AttributeDefinition> attributeDefinitions,
String tableName,
List<KeySchemaElement> keySchema,
ProvisionedThroughput provisionedThroughput)
The CreateTable operation adds a new table to your account.
|
DeleteItemResult |
deleteItem(DeleteItemRequest deleteItemRequest)
Deletes a single item in a table by primary key.
|
DeleteItemResult |
deleteItem(String tableName,
Map<String,AttributeValue> key)
Deletes a single item in a table by primary key.
|
DeleteItemResult |
deleteItem(String tableName,
Map<String,AttributeValue> key,
String returnValues)
Deletes a single item in a table by primary key.
|
DeleteTableResult |
deleteTable(DeleteTableRequest deleteTableRequest)
The DeleteTable operation deletes a table and all of its
items.
|
DeleteTableResult |
deleteTable(String tableName)
The DeleteTable operation deletes a table and all of its
items.
|
DescribeTableResult |
describeTable(DescribeTableRequest describeTableRequest)
Returns information about the table, including the current status of
the table, when it was created, the primary key schema, and any
indexes on the table.
|
DescribeTableResult |
describeTable(String tableName)
Returns information about the table, including the current status of
the table, when it was created, the primary key schema, and any
indexes on the table.
|
ResponseMetadata |
getCachedResponseMetadata(AmazonWebServiceRequest request)
Returns additional metadata for a previously executed successful request, typically used for
debugging issues where a service isn't acting as expected.
|
GetItemResult |
getItem(GetItemRequest getItemRequest)
The GetItem operation returns a set of attributes for the item
with the given primary key.
|
GetItemResult |
getItem(String tableName,
Map<String,AttributeValue> key)
The GetItem operation returns a set of attributes for the item
with the given primary key.
|
GetItemResult |
getItem(String tableName,
Map<String,AttributeValue> key,
Boolean consistentRead)
The GetItem operation returns a set of attributes for the item
with the given primary key.
|
ListTablesResult |
listTables()
Returns an array of table names associated with the current account
and endpoint.
|
ListTablesResult |
listTables(Integer limit)
Returns an array of table names associated with the current account
and endpoint.
|
ListTablesResult |
listTables(ListTablesRequest listTablesRequest)
Returns an array of table names associated with the current account
and endpoint.
|
ListTablesResult |
listTables(String exclusiveStartTableName)
Returns an array of table names associated with the current account
and endpoint.
|
ListTablesResult |
listTables(String exclusiveStartTableName,
Integer limit)
Returns an array of table names associated with the current account
and endpoint.
|
PutItemResult |
putItem(PutItemRequest putItemRequest)
Creates a new item, or replaces an old item with a new item.
|
PutItemResult |
putItem(String tableName,
Map<String,AttributeValue> item)
Creates a new item, or replaces an old item with a new item.
|
PutItemResult |
putItem(String tableName,
Map<String,AttributeValue> item,
String returnValues)
Creates a new item, or replaces an old item with a new item.
|
QueryResult |
query(QueryRequest queryRequest)
A Query operation uses the primary key of a table or a
secondary index to directly access items from that table or index.
|
ScanResult |
scan(ScanRequest scanRequest)
The Scan operation returns one or more items and item
attributes by accessing every item in a table or a secondary index.
|
ScanResult |
scan(String tableName,
List<String> attributesToGet)
The Scan operation returns one or more items and item
attributes by accessing every item in a table or a secondary index.
|
ScanResult |
scan(String tableName,
List<String> attributesToGet,
Map<String,Condition> scanFilter)
The Scan operation returns one or more items and item
attributes by accessing every item in a table or a secondary index.
|
ScanResult |
scan(String tableName,
Map<String,Condition> scanFilter)
The Scan operation returns one or more items and item
attributes by accessing every item in a table or a secondary index.
|
void |
setEndpoint(String endpoint)
Overrides the default endpoint for this client ("http://dynamodb.us-east-1.amazonaws.com/").
|
void |
setRegion(Region region)
An alternative to
setEndpoint(String), sets the
regional endpoint for this client's service calls. |
void |
shutdown()
Shuts down this client object, releasing any resources that might be held
open.
|
UpdateItemResult |
updateItem(String tableName,
Map<String,AttributeValue> key,
Map<String,AttributeValueUpdate> attributeUpdates)
Edits an existing item's attributes, or adds a new item to the table
if it does not already exist.
|
UpdateItemResult |
updateItem(String tableName,
Map<String,AttributeValue> key,
Map<String,AttributeValueUpdate> attributeUpdates,
String returnValues)
Edits an existing item's attributes, or adds a new item to the table
if it does not already exist.
|
UpdateItemResult |
updateItem(UpdateItemRequest updateItemRequest)
Edits an existing item's attributes, or adds a new item to the table
if it does not already exist.
|
UpdateTableResult |
updateTable(String tableName,
ProvisionedThroughput provisionedThroughput)
Updates the provisioned throughput for the given table, or manages
the global secondary indexes on the table.
|
UpdateTableResult |
updateTable(UpdateTableRequest updateTableRequest)
Updates the provisioned throughput for the given table, or manages
the global secondary indexes on the table.
|
void setEndpoint(String endpoint) throws IllegalArgumentException
Callers can pass in just the endpoint (ex: "dynamodb.us-east-1.amazonaws.com/") or a full
URL, including the protocol (ex: "http://dynamodb.us-east-1.amazonaws.com/"). If the
protocol is not specified here, the default protocol from this client's
ClientConfiguration will be used, which by default is HTTPS.
For more information on using AWS regions with the AWS SDK for Java, and a complete list of all available endpoints for all AWS services, see: http://developer.amazonwebservices.com/connect/entry.jspa?externalID=3912
This method is not threadsafe. An endpoint should be configured when the client is created and before any service requests are made. Changing it afterwards creates inevitable race conditions for any service requests in transit or retrying.
endpoint - The endpoint (ex: "dynamodb.us-east-1.amazonaws.com/") or a full URL,
including the protocol (ex: "http://dynamodb.us-east-1.amazonaws.com/") of
the region specific AWS endpoint this client will communicate
with.IllegalArgumentException - If any problems are detected with the specified endpoint.void setRegion(Region region) throws IllegalArgumentException
setEndpoint(String), sets the
regional endpoint for this client's service calls. Callers can use this
method to control which AWS region they want to work with.
By default, all service endpoints in all regions use the https protocol.
To use http instead, specify it in the ClientConfiguration
supplied at construction.
This method is not threadsafe. A region should be configured when the client is created and before any service requests are made. Changing it afterwards creates inevitable race conditions for any service requests in transit or retrying.
region - The region this client will communicate with. See
Region.getRegion(com.amazonaws.regions.Regions) for
accessing a given region.IllegalArgumentException - If the given region is null, or if this service isn't
available in the given region. See
Region.isServiceSupported(String)Region.getRegion(com.amazonaws.regions.Regions),
Region.createClient(Class, com.amazonaws.auth.AWSCredentialsProvider, ClientConfiguration)ScanResult scan(ScanRequest scanRequest) throws AmazonServiceException, AmazonClientException
The Scan operation returns one or more items and item attributes by accessing every item in a table or a secondary index. To have DynamoDB return fewer items, you can provide a ScanFilter operation.
If the total number of scanned items exceeds the maximum data set size limit of 1 MB, the scan stops and results are returned to the user as a LastEvaluatedKey value to continue the scan in a subsequent operation. The results also include the number of items exceeding the limit. A scan can result in no table data meeting the filter criteria.
The result set is eventually consistent.
By default, Scan operations proceed sequentially; however, for faster performance on a large table or secondary index, applications can request a parallel Scan operation by providing the Segment and TotalSegments parameters. For more information, see Parallel Scan in the Amazon DynamoDB Developer Guide .
scanRequest - Container for the necessary parameters to execute
the Scan service method on AmazonDynamoDBv2.ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.UpdateTableResult updateTable(UpdateTableRequest updateTableRequest) throws AmazonServiceException, AmazonClientException
Updates the provisioned throughput for the given table, or manages the global secondary indexes on the table.
You can increase or decrease the table's provisioned throughput values within the maximums and minimums listed in the Limits section in the Amazon DynamoDB Developer Guide .
In addition, you can use UpdateTable to add, modify or delete global secondary indexes on the table. For more information, see Managing Global Secondary Indexes in the Amazon DynamoDB Developer Guide .
The table must be in the ACTIVE state for
UpdateTable to succeed. UpdateTable is an asynchronous
operation; while executing the operation, the table is in the
UPDATING state. While the table is in the
UPDATING state, the table still has the provisioned
throughput from before the call. The table's new provisioned
throughput settings go into effect when the table returns to the
ACTIVE state; at that point, the UpdateTable
operation is complete.
updateTableRequest - Container for the necessary parameters to
execute the UpdateTable service method on AmazonDynamoDBv2.ResourceInUseExceptionResourceNotFoundExceptionLimitExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.DeleteTableResult deleteTable(DeleteTableRequest deleteTableRequest) throws AmazonServiceException, AmazonClientException
The DeleteTable operation deletes a table and all of its
items. After a DeleteTable request, the specified table is in
the DELETING state until DynamoDB completes the deletion.
If the table is in the ACTIVE state, you can delete it.
If a table is in CREATING or UPDATING
states, then DynamoDB returns a ResourceInUseException . If the
specified table does not exist, DynamoDB returns a
ResourceNotFoundException . If table is already in the
DELETING state, no error is returned.
NOTE: DynamoDB might continue to accept data read and write operations, such as GetItem and PutItem, on a table in the DELETING state until the table deletion is complete.
When you delete a table, any indexes on that table are also deleted.
Use the DescribeTable API to check the status of the table.
deleteTableRequest - Container for the necessary parameters to
execute the DeleteTable service method on AmazonDynamoDBv2.ResourceInUseExceptionResourceNotFoundExceptionLimitExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.BatchWriteItemResult batchWriteItem(BatchWriteItemRequest batchWriteItemRequest) throws AmazonServiceException, AmazonClientException
The BatchWriteItem operation puts or deletes multiple items in one or more tables. A single call to BatchWriteItem can write up to 16 MB of data, which can comprise as many as 25 put or delete requests. Individual items to be written can be as large as 400 KB.
NOTE: BatchWriteItem cannot update items. To update items, use the UpdateItem API.
The individual PutItem and DeleteItem operations specified in BatchWriteItem are atomic; however BatchWriteItem as a whole is not. If any requested operations fail because the table's provisioned throughput is exceeded or an internal processing failure occurs, the failed operations are returned in the UnprocessedItems response parameter. You can investigate and optionally resend the requests. Typically, you would call BatchWriteItem in a loop. Each iteration would check for unprocessed items and submit a new BatchWriteItem request with those unprocessed items until all items have been processed.
Note that if none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchWriteItem will return a ProvisionedThroughputExceededException .
IMPORTANT: If DynamoDB returns any unprocessed items, you should retry the batch operation on those items. However, we strongly recommend that you use an exponential backoff algorithm. If you retry the batch operation immediately, the underlying read or write requests can still fail due to throttling on the individual tables. If you delay the batch operation using exponential backoff, the individual requests in the batch are much more likely to succeed. For more information, see Batch Operations and Error Handling in the Amazon DynamoDB Developer Guide.
With BatchWriteItem , you can efficiently write or delete large amounts of data, such as from Amazon Elastic MapReduce (EMR), or copy data from another database into DynamoDB. In order to improve performance with these large-scale operations, BatchWriteItem does not behave in the same way as individual PutItem and DeleteItem calls would. For example, you cannot specify conditions on individual put and delete requests, and BatchWriteItem does not return deleted items in the response.
If you use a programming language that supports concurrency, such as Java, you can use threads to write items in parallel. Your application must include the necessary logic to manage the threads. With languages that don't support threading, such as PHP, you must update or delete the specified items one at a time. In both situations, BatchWriteItem provides an alternative where the API performs the specified put and delete operations in parallel, giving you the power of the thread pool approach without having to introduce complexity into your application.
Parallel processing reduces latency, but each specified put and delete request consumes the same number of write capacity units whether it is processed in parallel or not. Delete operations on nonexistent items consume one write capacity unit.
If one or more of the following is true, DynamoDB rejects the entire batch write operation:
One or more tables specified in the BatchWriteItem request does not exist.
Primary key attributes specified on an item in the request do not match those in the corresponding table's primary key schema.
You try to perform multiple operations on the same item in the same BatchWriteItem request. For example, you cannot put and delete the same item in the same BatchWriteItem request.
There are more than 25 requests in the batch.
Any individual item in a batch exceeds 400 KB.
The total request size exceeds 16 MB.
batchWriteItemRequest - Container for the necessary parameters to
execute the BatchWriteItem service method on AmazonDynamoDBv2.ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.DescribeTableResult describeTable(DescribeTableRequest describeTableRequest) throws AmazonServiceException, AmazonClientException
Returns information about the table, including the current status of the table, when it was created, the primary key schema, and any indexes on the table.
NOTE: If you issue a DescribeTable request immediately after a CreateTable request, DynamoDB might return a ResourceNotFoundException. This is because DescribeTable uses an eventually consistent query, and the metadata for your table might not be available at that moment. Wait for a few seconds, and then try the DescribeTable request again.
describeTableRequest - Container for the necessary parameters to
execute the DescribeTable service method on AmazonDynamoDBv2.ResourceNotFoundExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.GetItemResult getItem(GetItemRequest getItemRequest) throws AmazonServiceException, AmazonClientException
The GetItem operation returns a set of attributes for the item with the given primary key. If there is no matching item, GetItem does not return any data.
GetItem provides an eventually consistent read by default. If
your application requires a strongly consistent read, set
ConsistentRead to true . Although a strongly
consistent read might take more time than an eventually consistent
read, it always returns the last updated value.
getItemRequest - Container for the necessary parameters to
execute the GetItem service method on AmazonDynamoDBv2.ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.DeleteItemResult deleteItem(DeleteItemRequest deleteItemRequest) throws AmazonServiceException, AmazonClientException
Deletes a single item in a table by primary key. You can perform a conditional delete operation that deletes the item if it exists, or if it has an expected attribute value.
In addition to deleting an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.
Unless you specify conditions, the DeleteItem is an idempotent operation; running it multiple times on the same item or attribute does not result in an error response.
Conditional deletes are useful for deleting items only if specific conditions are met. If those conditions are met, DynamoDB performs the delete. Otherwise, the item is not deleted.
deleteItemRequest - Container for the necessary parameters to
execute the DeleteItem service method on AmazonDynamoDBv2.ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.CreateTableResult createTable(CreateTableRequest createTableRequest) throws AmazonServiceException, AmazonClientException
The CreateTable operation adds a new table to your account. In an AWS account, table names must be unique within each region. That is, you can have two tables with same name if you create the tables in different regions.
CreateTable is an asynchronous operation. Upon receiving a
CreateTable request, DynamoDB immediately returns a response
with a TableStatus of CREATING . After the table
is created, DynamoDB sets the TableStatus to
ACTIVE . You can perform read and write operations only
on an ACTIVE table.
You can optionally define secondary indexes on the new table, as part
of the CreateTable operation. If you want to create multiple
tables with secondary indexes on them, you must create the tables
sequentially. Only one table with secondary indexes can be in the
CREATING state at any given time.
You can use the DescribeTable API to check the table status.
createTableRequest - Container for the necessary parameters to
execute the CreateTable service method on AmazonDynamoDBv2.ResourceInUseExceptionLimitExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.QueryResult query(QueryRequest queryRequest) throws AmazonServiceException, AmazonClientException
A Query operation uses the primary key of a table or a secondary index to directly access items from that table or index.
Use the KeyConditionExpression parameter to provide a specific hash key value. The Query operation will return all of the items from the table or index with that hash key value. You can optionally narrow the scope of the Query operation by specifying a range key value and a comparison operator in KeyConditionExpression . You can use the ScanIndexForward parameter to get results in forward or reverse order, by range key or by index key.
Queries that do not return results consume the minimum number of read capacity units for that type of read operation.
If the total number of items meeting the query criteria exceeds the result set size limit of 1 MB, the query stops and results are returned to the user with the LastEvaluatedKey element to continue the query in a subsequent operation. Unlike a Scan operation, a Query operation never returns both an empty result set and a LastEvaluatedKey value. LastEvaluatedKey is only provided if the results exceed 1 MB, or if you have used the Limit parameter.
You can query a table, a local secondary index, or a global secondary
index. For a query on a table or on a local secondary index, you can
set the ConsistentRead parameter to true and
obtain a strongly consistent result. Global secondary indexes support
eventually consistent reads only, so do not specify
ConsistentRead when querying a global secondary index.
queryRequest - Container for the necessary parameters to execute
the Query service method on AmazonDynamoDBv2.ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.PutItemResult putItem(PutItemRequest putItemRequest) throws AmazonServiceException, AmazonClientException
Creates a new item, or replaces an old item with a new item. If an item that has the same primary key as the new item already exists in the specified table, the new item completely replaces the existing item. You can perform a conditional put operation (add a new item if one with the specified primary key doesn't exist), or replace an existing item if it has certain attribute values.
In addition to putting an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.
When you add an item, the primary key attribute(s) are the only required attributes. Attribute values cannot be null. String and Binary type attributes must have lengths greater than zero. Set type attributes cannot be empty. Requests with empty values will be rejected with a ValidationException exception.
You can request that PutItem return either a copy of the original item (before the update) or a copy of the updated item (after the update). For more information, see the ReturnValues description below.
NOTE: To prevent a new item from replacing an existing item, use a conditional put operation with ComparisonOperator set to NULL for the primary key attribute, or attributes.
For more information about using this API, see Working with Items in the Amazon DynamoDB Developer Guide .
putItemRequest - Container for the necessary parameters to
execute the PutItem service method on AmazonDynamoDBv2.ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.ListTablesResult listTables(ListTablesRequest listTablesRequest) throws AmazonServiceException, AmazonClientException
Returns an array of table names associated with the current account and endpoint. The output from ListTables is paginated, with each page returning a maximum of 100 table names.
listTablesRequest - Container for the necessary parameters to
execute the ListTables service method on AmazonDynamoDBv2.InternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.UpdateItemResult updateItem(UpdateItemRequest updateItemRequest) throws AmazonServiceException, AmazonClientException
Edits an existing item's attributes, or adds a new item to the table if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update on an existing item (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute values). If conditions are specified and the item does not exist, then the operation fails and a new item is not created.
You can also return the item's attribute values in the same UpdateItem operation using the ReturnValues parameter.
updateItemRequest - Container for the necessary parameters to
execute the UpdateItem service method on AmazonDynamoDBv2.ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.BatchGetItemResult batchGetItem(BatchGetItemRequest batchGetItemRequest) throws AmazonServiceException, AmazonClientException
The BatchGetItem operation returns the attributes of one or more items from one or more tables. You identify requested items by primary key.
A single operation can retrieve up to 16 MB of data, which can contain as many as 100 items. BatchGetItem will return a partial result if the response size limit is exceeded, the table's provisioned throughput is exceeded, or an internal processing failure occurs. If a partial result is returned, the operation returns a value for UnprocessedKeys . You can use this value to retry the operation starting with the next item to get.
For example, if you ask to retrieve 100 items, but each individual item is 300 KB in size, the system returns 52 items (so as not to exceed the 16 MB limit). It also returns an appropriate UnprocessedKeys value so you can get the next page of results. If desired, your application can include its own logic to assemble the pages of results into one data set.
If none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchGetItem will return a ProvisionedThroughputExceededException . If at least one of the items is successfully processed, then BatchGetItem completes successfully, while returning the keys of the unread items in UnprocessedKeys .
IMPORTANT: If DynamoDB returns any unprocessed items, you should retry the batch operation on those items. However, we strongly recommend that you use an exponential backoff algorithm. If you retry the batch operation immediately, the underlying read or write requests can still fail due to throttling on the individual tables. If you delay the batch operation using exponential backoff, the individual requests in the batch are much more likely to succeed. For more information, see Batch Operations and Error Handling in the Amazon DynamoDB Developer Guide.
By default, BatchGetItem performs eventually consistent reads
on every table in the request. If you want strongly consistent reads
instead, you can set ConsistentRead to true for
any or all tables.
In order to minimize response latency, BatchGetItem retrieves items in parallel.
When designing your application, keep in mind that DynamoDB does not return attributes in any particular order. To help parse the response by item, include the primary key values for the items in your request in the AttributesToGet parameter.
If a requested item does not exist, it is not returned in the result. Requests for nonexistent items consume the minimum read capacity units according to the type of read. For more information, see Capacity Units Calculations in the Amazon DynamoDB Developer Guide .
batchGetItemRequest - Container for the necessary parameters to
execute the BatchGetItem service method on AmazonDynamoDBv2.ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.ListTablesResult listTables() throws AmazonServiceException, AmazonClientException
Returns an array of table names associated with the current account and endpoint. The output from ListTables is paginated, with each page returning a maximum of 100 table names.
InternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.ScanResult scan(String tableName, List<String> attributesToGet) throws AmazonServiceException, AmazonClientException
The Scan operation returns one or more items and item attributes by accessing every item in a table or a secondary index. To have DynamoDB return fewer items, you can provide a ScanFilter operation.
If the total number of scanned items exceeds the maximum data set size limit of 1 MB, the scan stops and results are returned to the user as a LastEvaluatedKey value to continue the scan in a subsequent operation. The results also include the number of items exceeding the limit. A scan can result in no table data meeting the filter criteria.
The result set is eventually consistent.
By default, Scan operations proceed sequentially; however, for faster performance on a large table or secondary index, applications can request a parallel Scan operation by providing the Segment and TotalSegments parameters. For more information, see Parallel Scan in the Amazon DynamoDB Developer Guide .
tableName - The name of the table containing the requested items;
or, if you provide IndexName, the name of the table to
which that index belongs.attributesToGet - This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.ScanResult scan(String tableName, Map<String,Condition> scanFilter) throws AmazonServiceException, AmazonClientException
The Scan operation returns one or more items and item attributes by accessing every item in a table or a secondary index. To have DynamoDB return fewer items, you can provide a ScanFilter operation.
If the total number of scanned items exceeds the maximum data set size limit of 1 MB, the scan stops and results are returned to the user as a LastEvaluatedKey value to continue the scan in a subsequent operation. The results also include the number of items exceeding the limit. A scan can result in no table data meeting the filter criteria.
The result set is eventually consistent.
By default, Scan operations proceed sequentially; however, for faster performance on a large table or secondary index, applications can request a parallel Scan operation by providing the Segment and TotalSegments parameters. For more information, see Parallel Scan in the Amazon DynamoDB Developer Guide .
tableName - The name of the table containing the requested items;
or, if you provide IndexName, the name of the table to
which that index belongs.scanFilter - This is a legacy parameter, for backward compatibility. New applications should use FilterExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
A
condition that evaluates the scan results and returns only the desired
values. This parameter does not support attributes of type
List or Map.
If you specify more than one condition in the ScanFilter map, then by default all of the conditions must evaluate to true. In other words, the conditions are ANDed together. (You can use the ConditionalOperator parameter to OR the conditions instead. If you do this, then at least one of the conditions must evaluate to true, rather than all of them.)
Each ScanFilter element consists of an attribute name to compare, along with the following:
AttributeValueList - One or more values to evaluate against the supplied attribute. The number of values in the list depends on the operator specified in ComparisonOperator .
For type Number, value comparisons are numeric.
String value comparisons for greater than, equals, or less
than are based on ASCII character code values. For example,
a is greater than A, and a is
greater than B. For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.
For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.
For information on specifying data types in JSON, see JSON Data Format in the Amazon DynamoDB Developer Guide.
ComparisonOperator - A comparator for evaluating attributes. For example, equals, greater than, less than, etc.
The following comparison operators are available:
EQ | NE | LE |
LT | GE | GT | NOT_NULL | NULL | CONTAINS | NOT_CONTAINS | BEGINS_WITH
| IN | BETWEEN
For complete descriptions of all comparison operators, see Condition.
ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.ScanResult scan(String tableName, List<String> attributesToGet, Map<String,Condition> scanFilter) throws AmazonServiceException, AmazonClientException
The Scan operation returns one or more items and item attributes by accessing every item in a table or a secondary index. To have DynamoDB return fewer items, you can provide a ScanFilter operation.
If the total number of scanned items exceeds the maximum data set size limit of 1 MB, the scan stops and results are returned to the user as a LastEvaluatedKey value to continue the scan in a subsequent operation. The results also include the number of items exceeding the limit. A scan can result in no table data meeting the filter criteria.
The result set is eventually consistent.
By default, Scan operations proceed sequentially; however, for faster performance on a large table or secondary index, applications can request a parallel Scan operation by providing the Segment and TotalSegments parameters. For more information, see Parallel Scan in the Amazon DynamoDB Developer Guide .
tableName - The name of the table containing the requested items;
or, if you provide IndexName, the name of the table to
which that index belongs.attributesToGet - This is a legacy parameter, for backward compatibility. New applications should use ProjectionExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter allows you to retrieve attributes of type List or Map; however, it cannot retrieve individual elements within a List or a Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
scanFilter - This is a legacy parameter, for backward compatibility. New applications should use FilterExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
A
condition that evaluates the scan results and returns only the desired
values. This parameter does not support attributes of type
List or Map.
If you specify more than one condition in the ScanFilter map, then by default all of the conditions must evaluate to true. In other words, the conditions are ANDed together. (You can use the ConditionalOperator parameter to OR the conditions instead. If you do this, then at least one of the conditions must evaluate to true, rather than all of them.)
Each ScanFilter element consists of an attribute name to compare, along with the following:
AttributeValueList - One or more values to evaluate against the supplied attribute. The number of values in the list depends on the operator specified in ComparisonOperator .
For type Number, value comparisons are numeric.
String value comparisons for greater than, equals, or less
than are based on ASCII character code values. For example,
a is greater than A, and a is
greater than B. For a list of code values, see http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters.
For Binary, DynamoDB treats each byte of the binary data as unsigned when it compares binary values.
For information on specifying data types in JSON, see JSON Data Format in the Amazon DynamoDB Developer Guide.
ComparisonOperator - A comparator for evaluating attributes. For example, equals, greater than, less than, etc.
The following comparison operators are available:
EQ | NE | LE |
LT | GE | GT | NOT_NULL | NULL | CONTAINS | NOT_CONTAINS | BEGINS_WITH
| IN | BETWEEN
For complete descriptions of all comparison operators, see Condition.
ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.UpdateTableResult updateTable(String tableName, ProvisionedThroughput provisionedThroughput) throws AmazonServiceException, AmazonClientException
Updates the provisioned throughput for the given table, or manages the global secondary indexes on the table.
You can increase or decrease the table's provisioned throughput values within the maximums and minimums listed in the Limits section in the Amazon DynamoDB Developer Guide .
In addition, you can use UpdateTable to add, modify or delete global secondary indexes on the table. For more information, see Managing Global Secondary Indexes in the Amazon DynamoDB Developer Guide .
The table must be in the ACTIVE state for
UpdateTable to succeed. UpdateTable is an asynchronous
operation; while executing the operation, the table is in the
UPDATING state. While the table is in the
UPDATING state, the table still has the provisioned
throughput from before the call. The table's new provisioned
throughput settings go into effect when the table returns to the
ACTIVE state; at that point, the UpdateTable
operation is complete.
tableName - The name of the table to be updated.provisionedThroughput - Represents the provisioned throughput
settings for a specified table or index. The settings can be modified
using the UpdateTable operation. For current minimum and maximum provisioned throughput values, see Limits in the Amazon DynamoDB Developer Guide.
ResourceInUseExceptionResourceNotFoundExceptionLimitExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.DeleteTableResult deleteTable(String tableName) throws AmazonServiceException, AmazonClientException
The DeleteTable operation deletes a table and all of its
items. After a DeleteTable request, the specified table is in
the DELETING state until DynamoDB completes the deletion.
If the table is in the ACTIVE state, you can delete it.
If a table is in CREATING or UPDATING
states, then DynamoDB returns a ResourceInUseException . If the
specified table does not exist, DynamoDB returns a
ResourceNotFoundException . If table is already in the
DELETING state, no error is returned.
NOTE: DynamoDB might continue to accept data read and write operations, such as GetItem and PutItem, on a table in the DELETING state until the table deletion is complete.
When you delete a table, any indexes on that table are also deleted.
Use the DescribeTable API to check the status of the table.
tableName - The name of the table to delete.ResourceInUseExceptionResourceNotFoundExceptionLimitExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.BatchWriteItemResult batchWriteItem(Map<String,List<WriteRequest>> requestItems) throws AmazonServiceException, AmazonClientException
The BatchWriteItem operation puts or deletes multiple items in one or more tables. A single call to BatchWriteItem can write up to 16 MB of data, which can comprise as many as 25 put or delete requests. Individual items to be written can be as large as 400 KB.
NOTE: BatchWriteItem cannot update items. To update items, use the UpdateItem API.
The individual PutItem and DeleteItem operations specified in BatchWriteItem are atomic; however BatchWriteItem as a whole is not. If any requested operations fail because the table's provisioned throughput is exceeded or an internal processing failure occurs, the failed operations are returned in the UnprocessedItems response parameter. You can investigate and optionally resend the requests. Typically, you would call BatchWriteItem in a loop. Each iteration would check for unprocessed items and submit a new BatchWriteItem request with those unprocessed items until all items have been processed.
Note that if none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchWriteItem will return a ProvisionedThroughputExceededException .
IMPORTANT: If DynamoDB returns any unprocessed items, you should retry the batch operation on those items. However, we strongly recommend that you use an exponential backoff algorithm. If you retry the batch operation immediately, the underlying read or write requests can still fail due to throttling on the individual tables. If you delay the batch operation using exponential backoff, the individual requests in the batch are much more likely to succeed. For more information, see Batch Operations and Error Handling in the Amazon DynamoDB Developer Guide.
With BatchWriteItem , you can efficiently write or delete large amounts of data, such as from Amazon Elastic MapReduce (EMR), or copy data from another database into DynamoDB. In order to improve performance with these large-scale operations, BatchWriteItem does not behave in the same way as individual PutItem and DeleteItem calls would. For example, you cannot specify conditions on individual put and delete requests, and BatchWriteItem does not return deleted items in the response.
If you use a programming language that supports concurrency, such as Java, you can use threads to write items in parallel. Your application must include the necessary logic to manage the threads. With languages that don't support threading, such as PHP, you must update or delete the specified items one at a time. In both situations, BatchWriteItem provides an alternative where the API performs the specified put and delete operations in parallel, giving you the power of the thread pool approach without having to introduce complexity into your application.
Parallel processing reduces latency, but each specified put and delete request consumes the same number of write capacity units whether it is processed in parallel or not. Delete operations on nonexistent items consume one write capacity unit.
If one or more of the following is true, DynamoDB rejects the entire batch write operation:
One or more tables specified in the BatchWriteItem request does not exist.
Primary key attributes specified on an item in the request do not match those in the corresponding table's primary key schema.
You try to perform multiple operations on the same item in the same BatchWriteItem request. For example, you cannot put and delete the same item in the same BatchWriteItem request.
There are more than 25 requests in the batch.
Any individual item in a batch exceeds 400 KB.
The total request size exceeds 16 MB.
requestItems - A map of one or more table names and, for each
table, a list of operations to be performed (DeleteRequest or
PutRequest). Each element in the map consists of the following:
DeleteRequest - Perform a DeleteItem operation on the specified item. The item to be deleted is identified by a Key subelement:
Key - A map of primary key attribute values that uniquely identify the ! item. Each entry in this map consists of an attribute name and an attribute value. For each primary key, you must provide all of the key attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
PutRequest - Perform a PutItem operation on the specified item. The item to be put is identified by an Item subelement:
Item - A map of attributes and their values. Each entry in this map consists of an attribute name and an attribute value. Attribute values must not be null; string and binary type attributes must have lengths greater than zero; and set type attributes must not be empty. Requests that contain empty values will be rejected with a ValidationException exception.
If you specify any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition.
ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.DescribeTableResult describeTable(String tableName) throws AmazonServiceException, AmazonClientException
Returns information about the table, including the current status of the table, when it was created, the primary key schema, and any indexes on the table.
NOTE: If you issue a DescribeTable request immediately after a CreateTable request, DynamoDB might return a ResourceNotFoundException. This is because DescribeTable uses an eventually consistent query, and the metadata for your table might not be available at that moment. Wait for a few seconds, and then try the DescribeTable request again.
tableName - The name of the table to describe.ResourceNotFoundExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.GetItemResult getItem(String tableName, Map<String,AttributeValue> key) throws AmazonServiceException, AmazonClientException
The GetItem operation returns a set of attributes for the item with the given primary key. If there is no matching item, GetItem does not return any data.
GetItem provides an eventually consistent read by default. If
your application requires a strongly consistent read, set
ConsistentRead to true . Although a strongly
consistent read might take more time than an eventually consistent
read, it always returns the last updated value.
tableName - The name of the table containing the requested item.key - A map of attribute names to AttributeValue objects,
representing the primary key of the item to retrieve. For the primary key, you must provide all of the attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.GetItemResult getItem(String tableName, Map<String,AttributeValue> key, Boolean consistentRead) throws AmazonServiceException, AmazonClientException
The GetItem operation returns a set of attributes for the item with the given primary key. If there is no matching item, GetItem does not return any data.
GetItem provides an eventually consistent read by default. If
your application requires a strongly consistent read, set
ConsistentRead to true . Although a strongly
consistent read might take more time than an eventually consistent
read, it always returns the last updated value.
tableName - The name of the table containing the requested item.key - A map of attribute names to AttributeValue objects,
representing the primary key of the item to retrieve. For the primary key, you must provide all of the attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
consistentRead - A value that if set to true, then
the operation uses strongly consistent reads; otherwise, eventually
consistent reads are used.ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.DeleteItemResult deleteItem(String tableName, Map<String,AttributeValue> key) throws AmazonServiceException, AmazonClientException
Deletes a single item in a table by primary key. You can perform a conditional delete operation that deletes the item if it exists, or if it has an expected attribute value.
In addition to deleting an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.
Unless you specify conditions, the DeleteItem is an idempotent operation; running it multiple times on the same item or attribute does not result in an error response.
Conditional deletes are useful for deleting items only if specific conditions are met. If those conditions are met, DynamoDB performs the delete. Otherwise, the item is not deleted.
tableName - The name of the table from which to delete the item.key - A map of attribute names to AttributeValue objects,
representing the primary key of the item to delete. For the primary key, you must provide all of the attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.DeleteItemResult deleteItem(String tableName, Map<String,AttributeValue> key, String returnValues) throws AmazonServiceException, AmazonClientException
Deletes a single item in a table by primary key. You can perform a conditional delete operation that deletes the item if it exists, or if it has an expected attribute value.
In addition to deleting an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.
Unless you specify conditions, the DeleteItem is an idempotent operation; running it multiple times on the same item or attribute does not result in an error response.
Conditional deletes are useful for deleting items only if specific conditions are met. If those conditions are met, DynamoDB performs the delete. Otherwise, the item is not deleted.
tableName - The name of the table from which to delete the item.key - A map of attribute names to AttributeValue objects,
representing the primary key of the item to delete. For the primary key, you must provide all of the attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
returnValues - Use ReturnValues if you want to get the
item attributes as they appeared before they were deleted. For
DeleteItem, the valid values are: NONE - If ReturnValues is not specified, or if
its value is NONE, then nothing is returned. (This
setting is the default for ReturnValues.)
ALL_OLD - The content of the old item is returned.
ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.CreateTableResult createTable(List<AttributeDefinition> attributeDefinitions, String tableName, List<KeySchemaElement> keySchema, ProvisionedThroughput provisionedThroughput) throws AmazonServiceException, AmazonClientException
The CreateTable operation adds a new table to your account. In an AWS account, table names must be unique within each region. That is, you can have two tables with same name if you create the tables in different regions.
CreateTable is an asynchronous operation. Upon receiving a
CreateTable request, DynamoDB immediately returns a response
with a TableStatus of CREATING . After the table
is created, DynamoDB sets the TableStatus to
ACTIVE . You can perform read and write operations only
on an ACTIVE table.
You can optionally define secondary indexes on the new table, as part
of the CreateTable operation. If you want to create multiple
tables with secondary indexes on them, you must create the tables
sequentially. Only one table with secondary indexes can be in the
CREATING state at any given time.
You can use the DescribeTable API to check the table status.
attributeDefinitions - An array of attributes that describe the
key schema for the table and indexes.tableName - The name of the table to create.keySchema - Specifies the attributes that make up the primary key
for a table or an index. The attributes in KeySchema must also
be defined in the AttributeDefinitions array. For more
information, see Data
Model in the Amazon DynamoDB Developer Guide. Each KeySchemaElement in the array is composed of:
AttributeName - The name of this key attribute.
KeyType - Determines whether the key attribute is
HASH or RANGE.
For a primary
key that consists of a hash attribute, you must provide exactly one
element with a KeyType of HASH.
For a primary
key that consists of hash and range attributes, you must provide
exactly two elements, in this order: The first element must have a
KeyType of HASH, and the second element must have
a KeyType of RANGE.
For more information, see Specifying the Primary Key in the Amazon DynamoDB Developer Guide.
provisionedThroughput - Represents the provisioned throughput
settings for a specified table or index. The settings can be modified
using the UpdateTable operation. For current minimum and maximum provisioned throughput values, see Limits in the Amazon DynamoDB Developer Guide.
ResourceInUseExceptionLimitExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.PutItemResult putItem(String tableName, Map<String,AttributeValue> item) throws AmazonServiceException, AmazonClientException
Creates a new item, or replaces an old item with a new item. If an item that has the same primary key as the new item already exists in the specified table, the new item completely replaces the existing item. You can perform a conditional put operation (add a new item if one with the specified primary key doesn't exist), or replace an existing item if it has certain attribute values.
In addition to putting an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.
When you add an item, the primary key attribute(s) are the only required attributes. Attribute values cannot be null. String and Binary type attributes must have lengths greater than zero. Set type attributes cannot be empty. Requests with empty values will be rejected with a ValidationException exception.
You can request that PutItem return either a copy of the original item (before the update) or a copy of the updated item (after the update). For more information, see the ReturnValues description below.
NOTE: To prevent a new item from replacing an existing item, use a conditional put operation with ComparisonOperator set to NULL for the primary key attribute, or attributes.
For more information about using this API, see Working with Items in the Amazon DynamoDB Developer Guide .
tableName - The name of the table to contain the item.item - A map of attribute name/value pairs, one for each
attribute. Only the primary key attributes are required; you can
optionally provide other attribute name-value pairs for the item.
You must provide all of the attributes for the primary key. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
If you specify any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition.
For more information about primary keys, see Primary Key in the Amazon DynamoDB Developer Guide.
Each element in the Item map is an AttributeValue object.
ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.PutItemResult putItem(String tableName, Map<String,AttributeValue> item, String returnValues) throws AmazonServiceException, AmazonClientException
Creates a new item, or replaces an old item with a new item. If an item that has the same primary key as the new item already exists in the specified table, the new item completely replaces the existing item. You can perform a conditional put operation (add a new item if one with the specified primary key doesn't exist), or replace an existing item if it has certain attribute values.
In addition to putting an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.
When you add an item, the primary key attribute(s) are the only required attributes. Attribute values cannot be null. String and Binary type attributes must have lengths greater than zero. Set type attributes cannot be empty. Requests with empty values will be rejected with a ValidationException exception.
You can request that PutItem return either a copy of the original item (before the update) or a copy of the updated item (after the update). For more information, see the ReturnValues description below.
NOTE: To prevent a new item from replacing an existing item, use a conditional put operation with ComparisonOperator set to NULL for the primary key attribute, or attributes.
For more information about using this API, see Working with Items in the Amazon DynamoDB Developer Guide .
tableName - The name of the table to contain the item.item - A map of attribute name/value pairs, one for each
attribute. Only the primary key attributes are required; you can
optionally provide other attribute name-value pairs for the item.
You must provide all of the attributes for the primary key. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
If you specify any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition.
For more information about primary keys, see Primary Key in the Amazon DynamoDB Developer Guide.
Each element in the Item map is an AttributeValue object.
returnValues - Use ReturnValues if you want to get the
item attributes as they appeared before they were updated with the
PutItem request. For PutItem, the valid values are: NONE - If ReturnValues is not specified,
or if its value is NONE, then nothing is returned. (This
setting is the default for ReturnValues.)
ALL_OLD - If PutItem overwrote an attribute
name-value pair, then the content of the old item is returned.
ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.ListTablesResult listTables(String exclusiveStartTableName) throws AmazonServiceException, AmazonClientException
Returns an array of table names associated with the current account and endpoint. The output from ListTables is paginated, with each page returning a maximum of 100 table names.
exclusiveStartTableName - The first table name that this
operation will evaluate. Use the value that was returned for
LastEvaluatedTableName in a previous operation, so that you can
obtain the next page of results.InternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.ListTablesResult listTables(String exclusiveStartTableName, Integer limit) throws AmazonServiceException, AmazonClientException
Returns an array of table names associated with the current account and endpoint. The output from ListTables is paginated, with each page returning a maximum of 100 table names.
exclusiveStartTableName - The first table name that this
operation will evaluate. Use the value that was returned for
LastEvaluatedTableName in a previous operation, so that you can
obtain the next page of results.limit - A maximum number of table names to return. If this
parameter is not specified, the limit is 100.InternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.ListTablesResult listTables(Integer limit) throws AmazonServiceException, AmazonClientException
Returns an array of table names associated with the current account and endpoint. The output from ListTables is paginated, with each page returning a maximum of 100 table names.
limit - A maximum number of table names to return. If this
parameter is not specified, the limit is 100.InternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.UpdateItemResult updateItem(String tableName, Map<String,AttributeValue> key, Map<String,AttributeValueUpdate> attributeUpdates) throws AmazonServiceException, AmazonClientException
Edits an existing item's attributes, or adds a new item to the table if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update on an existing item (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute values). If conditions are specified and the item does not exist, then the operation fails and a new item is not created.
You can also return the item's attribute values in the same UpdateItem operation using the ReturnValues parameter.
tableName - The name of the table containing the item to update.key - The primary key of the item to be updated. Each element
consists of an attribute name and a value for that attribute. For the primary key, you must provide all of the attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
attributeUpdates - This is a legacy parameter, for backward compatibility. New applications should use UpdateExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter can be used for modifying top-level attributes; however, it does not support individual list or map elements.
The names of attributes to be modified, the action to perform on each, and the new value for each. If you are updating an attribute that is an index key attribute for any indexes on that table, the attribute type must match the index key type defined in the AttributesDefinition of the table description. You can use UpdateItem to update any nonkey attributes.
Attribute values cannot be null. String and Binary type attributes must have lengths greater than zero. Set type attributes must not be empty. Requests with empty values will be rejected with a ValidationException exception.
Each AttributeUpdates element consists of an attribute name to modify, along with the following:
Value - The new value, if applicable, for this attribute.
Action - A value that
specifies how to perform the update. This action is only valid for an
existing attribute whose data type is Number or is a set; do not use
ADD for other data types.
If an item with the specified primary key is found in the table, the following values perform the following actions:
PUT - Adds
the specified attribute to the item. If the attribute already exists,
it is replaced by the new value.
DELETE -
Removes the attribute and its value, if no value is specified for
DELETE. The data type of the specified value must match
the existing value's data type.
If a set of values is specified,
then those values are subtracted from the old set. For example, if the
attribute value was the set [a,b,c] and the
DELETE action specifies [a,c], then the
final attribute value is [b]. Specifying an empty set is
an error.
ADD - Adds the specified value to
the item, if the attribute does not already exist. If the attribute
does exist, then the behavior of ADD depends on the data
type of the attribute:
If the existing attribute is a
number, and if Value is also a number, then Value is
mathematically added to the existing attribute. If Value is a
negative number, then it is subtracted from the existing attribute.
If you use Similarly, if you use
ADD to increment or decrement a
number value for an item that doesn't exist before the update,
DynamoDB uses 0 as the initial value. ADD for an existing item to increment or decrement an
attribute value that doesn't exist before the update, DynamoDB uses
0 as the initial value. For example, suppose that the
item you want to update doesn't have an attribute named
itemcount, but you decide to ADD the number
3 to this attribute anyway. DynamoDB will create the
itemcount attribute, set its initial value to 0,
and finally add 3 to it. The result will be a new
itemcount attribute, with a value of 3.
If the existing data type is a set, and if Value
is also a set, then Value is appended to the existing set. For
example, if the attribute value is the set [1,2], and the
ADD action specified [3], then the final
attribute value is [1,2,3]. An error occurs if an
ADD action is specified for a set attribute and the
attribute type specified does not match the existing set type.
Both sets must have the same primitive data type. For example, if the existing data type is a set of strings, Value must also be a set of strings.
If no item with the specified key is found in the table, the following values perform the following actions:
PUT - Causes DynamoDB to
create a new item with the specified primary key, and then adds the
attribute.
DELETE - Nothing happens,
because attributes cannot be deleted from a nonexistent item. The
operation succeeds, but DynamoDB does not create a new item.
ADD - Causes DynamoDB to create an item with the
supplied primary key and number (or set of numbers) for the attribute
value. The only data types allowed are Number and Number Set.
If you provide any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition.
ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.UpdateItemResult updateItem(String tableName, Map<String,AttributeValue> key, Map<String,AttributeValueUpdate> attributeUpdates, String returnValues) throws AmazonServiceException, AmazonClientException
Edits an existing item's attributes, or adds a new item to the table if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update on an existing item (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute values). If conditions are specified and the item does not exist, then the operation fails and a new item is not created.
You can also return the item's attribute values in the same UpdateItem operation using the ReturnValues parameter.
tableName - The name of the table containing the item to update.key - The primary key of the item to be updated. Each element
consists of an attribute name and a value for that attribute. For the primary key, you must provide all of the attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
attributeUpdates - This is a legacy parameter, for backward compatibility. New applications should use UpdateExpression instead. Do not combine legacy parameters and expression parameters in a single API call; otherwise, DynamoDB will return a ValidationException exception.
This parameter can be used for modifying top-level attributes; however, it does not support individual list or map elements.
The names of attributes to be modified, the action to perform on each, and the new value for each. If you are updating an attribute that is an index key attribute for any indexes on that table, the attribute type must match the index key type defined in the AttributesDefinition of the table description. You can use UpdateItem to update any nonkey attributes.
Attribute values cannot be null. String and Binary type attributes must have lengths greater than zero. Set type attributes must not be empty. Requests with empty values will be rejected with a ValidationException exception.
Each AttributeUpdates element consists of an attribute name to modify, along with the following:
Value - The new value, if applicable, for this attribute.
Action - A value that
specifies how to perform the update. This action is only valid for an
existing attribute whose data type is Number or is a set; do not use
ADD for other data types.
If an item with the specified primary key is found in the table, the following values perform the following actions:
PUT - Adds
the specified attribute to the item. If the attribute already exists,
it is replaced by the new value.
DELETE -
Removes the attribute and its value, if no value is specified for
DELETE. The data type of the specified value must match
the existing value's data type.
If a set of values is specified,
then those values are subtracted from the old set. For example, if the
attribute value was the set [a,b,c] and the
DELETE action specifies [a,c], then the
final attribute value is [b]. Specifying an empty set is
an error.
ADD - Adds the specified value to
the item, if the attribute does not already exist. If the attribute
does exist, then the behavior of ADD depends on the data
type of the attribute:
If the existing attribute is a
number, and if Value is also a number, then Value is
mathematically added to the existing attribute. If Value is a
negative number, then it is subtracted from the existing attribute.
If you use Similarly, if you use
ADD to increment or decrement a
number value for an item that doesn't exist before the update,
DynamoDB uses 0 as the initial value. ADD for an existing item to increment or decrement an
attribute value that doesn't exist before the update, DynamoDB uses
0 as the initial value. For example, suppose that the
item you want to update doesn't have an attribute named
itemcount, but you decide to ADD the number
3 to this attribute anyway. DynamoDB will create the
itemcount attribute, set its initial value to 0,
and finally add 3 to it. The result will be a new
itemcount attribute, with a value of 3.
If the existing data type is a set, and if Value
is also a set, then Value is appended to the existing set. For
example, if the attribute value is the set [1,2], and the
ADD action specified [3], then the final
attribute value is [1,2,3]. An error occurs if an
ADD action is specified for a set attribute and the
attribute type specified does not match the existing set type.
Both sets must have the same primitive data type. For example, if the existing data type is a set of strings, Value must also be a set of strings.
If no item with the specified key is found in the table, the following values perform the following actions:
PUT - Causes DynamoDB to
create a new item with the specified primary key, and then adds the
attribute.
DELETE - Nothing happens,
because attributes cannot be deleted from a nonexistent item. The
operation succeeds, but DynamoDB does not create a new item.
ADD - Causes DynamoDB to create an item with the
supplied primary key and number (or set of numbers) for the attribute
value. The only data types allowed are Number and Number Set.
If you provide any attributes that are part of an index key, then the data types for those attributes must match those of the schema in the table's attribute definition.
returnValues - Use ReturnValues if you want to get the
item attributes as they appeared either before or after they were
updated. For UpdateItem, the valid values are: NONE - If ReturnValues is not specified, or if
its value is NONE, then nothing is returned. (This
setting is the default for ReturnValues.)
ALL_OLD - If UpdateItem overwrote an attribute
name-value pair, then the content of the old item is returned.
UPDATED_OLD - The old versions of only the
updated attributes are returned.
ALL_NEW -
All of the attributes of the new version of the item are returned.
UPDATED_NEW - The new versions of only the
updated attributes are returned.
ItemCollectionSizeLimitExceededExceptionResourceNotFoundExceptionConditionalCheckFailedExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.BatchGetItemResult batchGetItem(Map<String,KeysAndAttributes> requestItems, String returnConsumedCapacity) throws AmazonServiceException, AmazonClientException
The BatchGetItem operation returns the attributes of one or more items from one or more tables. You identify requested items by primary key.
A single operation can retrieve up to 16 MB of data, which can contain as many as 100 items. BatchGetItem will return a partial result if the response size limit is exceeded, the table's provisioned throughput is exceeded, or an internal processing failure occurs. If a partial result is returned, the operation returns a value for UnprocessedKeys . You can use this value to retry the operation starting with the next item to get.
For example, if you ask to retrieve 100 items, but each individual item is 300 KB in size, the system returns 52 items (so as not to exceed the 16 MB limit). It also returns an appropriate UnprocessedKeys value so you can get the next page of results. If desired, your application can include its own logic to assemble the pages of results into one data set.
If none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchGetItem will return a ProvisionedThroughputExceededException . If at least one of the items is successfully processed, then BatchGetItem completes successfully, while returning the keys of the unread items in UnprocessedKeys .
IMPORTANT: If DynamoDB returns any unprocessed items, you should retry the batch operation on those items. However, we strongly recommend that you use an exponential backoff algorithm. If you retry the batch operation immediately, the underlying read or write requests can still fail due to throttling on the individual tables. If you delay the batch operation using exponential backoff, the individual requests in the batch are much more likely to succeed. For more information, see Batch Operations and Error Handling in the Amazon DynamoDB Developer Guide.
By default, BatchGetItem performs eventually consistent reads
on every table in the request. If you want strongly consistent reads
instead, you can set ConsistentRead to true for
any or all tables.
In order to minimize response latency, BatchGetItem retrieves items in parallel.
When designing your application, keep in mind that DynamoDB does not return attributes in any particular order. To help parse the response by item, include the primary key values for the items in your request in the AttributesToGet parameter.
If a requested item does not exist, it is not returned in the result. Requests for nonexistent items consume the minimum read capacity units according to the type of read. For more information, see Capacity Units Calculations in the Amazon DynamoDB Developer Guide .
requestItems - A map of one or more table names and, for each
table, a map that describes one or more items to retrieve from that
table. Each table name can be used only once per BatchGetItem
request. Each element in the map of items to retrieve consists of the following:
ConsistentRead - If
true, a strongly consistent read is used; if
false (the default), an eventually consistent read is
used.
ExpressionAttributeNames - One or more substitution tokens for attribute names in the ProjectionExpression parameter. The following are some use cases for using ExpressionAttributeNames:
To access an attribute whose name conflicts with a DynamoDB reserved word.
To create a placeholder for repeating occurrences of an attribute name in an expression.
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
Keys - An array of primary key attribute values that define specific items in the table. For each primary key, you must provide all of the key attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
ProjectionExpression - A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.
If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
AttributesToGet - This is a
legacy parameter, for backward compatibility. New applications should
use ProjectionExpression instead. Do not combine legacy
parameters and expression parameters in a single API call; otherwise,
DynamoDB will return a ValidationException exception. This
parameter allows you to retrieve attributes of type List or Map;
however, it cannot retrieve individual elements within a List or a
Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
returnConsumedCapacity - A value that if set to
TOTAL, the response includes ConsumedCapacity data
for tables and indexes. If set to INDEXES, the response
includes ConsumedCapacity for indexes. If set to
NONE (the default), ConsumedCapacity is not
included in the response.ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.BatchGetItemResult batchGetItem(Map<String,KeysAndAttributes> requestItems) throws AmazonServiceException, AmazonClientException
The BatchGetItem operation returns the attributes of one or more items from one or more tables. You identify requested items by primary key.
A single operation can retrieve up to 16 MB of data, which can contain as many as 100 items. BatchGetItem will return a partial result if the response size limit is exceeded, the table's provisioned throughput is exceeded, or an internal processing failure occurs. If a partial result is returned, the operation returns a value for UnprocessedKeys . You can use this value to retry the operation starting with the next item to get.
For example, if you ask to retrieve 100 items, but each individual item is 300 KB in size, the system returns 52 items (so as not to exceed the 16 MB limit). It also returns an appropriate UnprocessedKeys value so you can get the next page of results. If desired, your application can include its own logic to assemble the pages of results into one data set.
If none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchGetItem will return a ProvisionedThroughputExceededException . If at least one of the items is successfully processed, then BatchGetItem completes successfully, while returning the keys of the unread items in UnprocessedKeys .
IMPORTANT: If DynamoDB returns any unprocessed items, you should retry the batch operation on those items. However, we strongly recommend that you use an exponential backoff algorithm. If you retry the batch operation immediately, the underlying read or write requests can still fail due to throttling on the individual tables. If you delay the batch operation using exponential backoff, the individual requests in the batch are much more likely to succeed. For more information, see Batch Operations and Error Handling in the Amazon DynamoDB Developer Guide.
By default, BatchGetItem performs eventually consistent reads
on every table in the request. If you want strongly consistent reads
instead, you can set ConsistentRead to true for
any or all tables.
In order to minimize response latency, BatchGetItem retrieves items in parallel.
When designing your application, keep in mind that DynamoDB does not return attributes in any particular order. To help parse the response by item, include the primary key values for the items in your request in the AttributesToGet parameter.
If a requested item does not exist, it is not returned in the result. Requests for nonexistent items consume the minimum read capacity units according to the type of read. For more information, see Capacity Units Calculations in the Amazon DynamoDB Developer Guide .
requestItems - A map of one or more table names and, for each
table, a map that describes one or more items to retrieve from that
table. Each table name can be used only once per BatchGetItem
request. Each element in the map of items to retrieve consists of the following:
ConsistentRead - If
true, a strongly consistent read is used; if
false (the default), an eventually consistent read is
used.
ExpressionAttributeNames - One or more substitution tokens for attribute names in the ProjectionExpression parameter. The following are some use cases for using ExpressionAttributeNames:
To access an attribute whose name conflicts with a DynamoDB reserved word.
To create a placeholder for repeating occurrences of an attribute name in an expression.
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for ExpressionAttributeNames:
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
Keys - An array of primary key attribute values that define specific items in the table. For each primary key, you must provide all of the key attributes. For example, with a hash type primary key, you only need to provide the hash attribute. For a hash-and-range type primary key, you must provide both the hash attribute and the range attribute.
ProjectionExpression - A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.
If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
AttributesToGet - This is a
legacy parameter, for backward compatibility. New applications should
use ProjectionExpression instead. Do not combine legacy
parameters and expression parameters in a single API call; otherwise,
DynamoDB will return a ValidationException exception. This
parameter allows you to retrieve attributes of type List or Map;
however, it cannot retrieve individual elements within a List or a
Map.
The names of one or more attributes to retrieve. If no attribute names are provided, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
Note that AttributesToGet has no effect on provisioned throughput consumption. DynamoDB determines capacity units consumed based on item size, not on the amount of data that is returned to an application.
ResourceNotFoundExceptionProvisionedThroughputExceededExceptionInternalServerErrorExceptionAmazonClientException - If any internal errors are encountered inside the client while
attempting to make the request or handle the response. For example
if a network connection is not available.AmazonServiceException - If an error response is returned by AmazonDynamoDBv2 indicating
either a problem with the data in the request, or a server side issue.void shutdown()
ResponseMetadata getCachedResponseMetadata(AmazonWebServiceRequest request)
Response metadata is only cached for a limited period of time, so if you need to access this extra diagnostic information for an executed request, you should use this method to retrieve it as soon as possible after executing a request.
request - The originally executed request.Copyright © 2015. All rights reserved.