PgResultSetMetaData (PostgreSQL JDBC Driver

java.lang.Object
- org.postgresql.jdbc.PgResultSetMetaData

All Implemented Interfaces:: ResultSetMetaData, Wrapper, PGResultSetMetaData

public class PgResultSetMetaData
extends Object
implements ResultSetMetaData, PGResultSetMetaData

Field Summary

Fields
Modifier and Type Field and Description

protected BaseConnection connection

protected Field[] fields
- Fields inherited from interface java.sql.ResultSetMetaData
  columnNoNulls, columnNullable, columnNullableUnknown

Fields
Modifier and Type	Field and Description
`protected BaseConnection`	`connection`
`protected Field[]`	`fields`

Constructor Summary

Constructors
Constructor and Description
`PgResultSetMetaData(BaseConnection connection, Field[] fields)` Initialise for a result with a tuple set and a field descriptor set

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`String`	`getBaseColumnName(int column)` Returns the underlying column name of a query result, or "" if it is unable to be determined.
`String`	`getBaseSchemaName(int column)` Returns the underlying schema name of query result, or "" if it is unable to be determined.
`String`	`getBaseTableName(int column)` Returns the underlying table name of query result, or "" if it is unable to be determined.
`String`	`getCatalogName(int column)` Gets the designated column's table's catalog name.
`String`	`getColumnClassName(int column)` Returns the fully-qualified name of the Java class whose instances are manufactured if the method `ResultSet.getObject` is called to retrieve a value from the column.
`int`	`getColumnCount()` Returns the number of columns in this `ResultSet` object.
`int`	`getColumnDisplaySize(int column)` Indicates the designated column's normal maximum width in characters.
`String`	`getColumnLabel(int column)` Gets the designated column's suggested title for use in printouts and displays.
`String`	`getColumnName(int column)` Get the designated column's name.
`int`	`getColumnType(int column)` Retrieves the designated column's SQL type.
`String`	`getColumnTypeName(int column)` Retrieves the designated column's database-specific type name.
`protected Field`	`getField(int columnIndex)` For several routines in this package, we need to convert a columnIndex into a Field[] descriptor.
`int`	`getFormat(int column)` Is a column Text or Binary?
`protected String`	`getPGType(int columnIndex)`
`int`	`getPrecision(int column)` Get the designated column's specified column size.
`int`	`getScale(int column)` Gets the designated column's number of digits to right of the decimal point.
`String`	`getSchemaName(int column)` Get the designated column's table's schema.
`protected int`	`getSQLType(int columnIndex)`
`String`	`getTableName(int column)` Gets the designated column's table name.
`boolean`	`isAutoIncrement(int column)` Indicates whether the designated column is automatically numbered.
`boolean`	`isCaseSensitive(int column)` Indicates whether a column's case matters.
`boolean`	`isCurrency(int column)` Indicates whether the designated column is a cash value.
`boolean`	`isDefinitelyWritable(int column)` Indicates whether a write on the designated column will definitely succeed.
`int`	`isNullable(int column)` Indicates the nullability of values in the designated column.
`boolean`	`isReadOnly(int column)` Indicates whether the designated column is definitely not writable.
`boolean`	`isSearchable(int column)` Indicates whether the designated column can be used in a where clause.
`boolean`	`isSigned(int column)` Indicates whether values in the designated column are signed numbers.
`boolean`	`isWrapperFor(Class<?> iface)` Returns true if this either implements the interface argument or is directly or indirectly a wrapper for an object that does.
`boolean`	`isWritable(int column)` Indicates whether it is possible for a write on the designated column to succeed.
`<T> T`	`unwrap(Class<T> iface)` Returns an object that implements the given interface to allow access to non-standard methods, or standard methods not exposed by the proxy.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - connection
```
protected final BaseConnection connection
```
  - fields
```
protected final Field[] fields
```
- Constructor Detail
  - PgResultSetMetaData
```
public PgResultSetMetaData(BaseConnection connection,
                           Field[] fields)
```
    Initialise for a result with a tuple set and a field descriptor set
    
    Parameters:
    
    connection - the connection to retrieve metadata
    
    fields - the array of field descriptors
- Method Detail
  - getColumnCount
```
public int getColumnCount()
                   throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Returns the number of columns in this ResultSet object.
    
    Specified by:
    
    getColumnCount in interface ResultSetMetaData
    
    Returns:
    
    the number of columns
    
    Throws:
    
    SQLException - if a database access error occurs
  - isAutoIncrement
```
public boolean isAutoIncrement(int column)
                        throws SQLException
```
    Indicates whether the designated column is automatically numbered.
    It is believed that PostgreSQL does not support this feature.
    
    Specified by:
    
    isAutoIncrement in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2...
    
    Returns:
    
    true if so
    
    Throws:
    
    SQLException - if a database access error occurs
  - isCaseSensitive
```
public boolean isCaseSensitive(int column)
                        throws SQLException
```
    Indicates whether a column's case matters.
    Does a column's case matter? ASSUMPTION: Any field that is not obviously case insensitive is assumed to be case sensitive
    
    Specified by:
    
    isCaseSensitive in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2...
    
    Returns:
    
    true if so
    
    Throws:
    
    SQLException - if a database access error occurs
  - isSearchable
```
public boolean isSearchable(int column)
                     throws SQLException
```
    Indicates whether the designated column can be used in a where clause.
    Can the column be used in a WHERE clause? Basically for this, I split the functions into two types: recognised types (which are always useable), and OTHER types (which may or may not be useable). The OTHER types, for now, I will assume they are useable. We should really query the catalog to see if they are useable.
    
    Specified by:
    
    isSearchable in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2...
    
    Returns:
    
    true if they can be used in a WHERE clause
    
    Throws:
    
    SQLException - if a database access error occurs
  - isCurrency
```
public boolean isCurrency(int column)
                   throws SQLException
```
    Indicates whether the designated column is a cash value.
    Is the column a cash value? 6.1 introduced the cash/money type, which haven't been incorporated as of 970414, so I just check the type name for both 'cash' and 'money'
    
    Specified by:
    
    isCurrency in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2...
    
    Returns:
    
    true if its a cash column
    
    Throws:
    
    SQLException - if a database access error occurs
  - isNullable
```
public int isNullable(int column)
               throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Indicates the nullability of values in the designated column.
    
    Specified by:
    
    isNullable in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    the nullability status of the given column; one of columnNoNulls, columnNullable or columnNullableUnknown
    
    Throws:
    
    SQLException - if a database access error occurs
  - isSigned
```
public boolean isSigned(int column)
                 throws SQLException
```
    Indicates whether values in the designated column are signed numbers.
    Is the column a signed number? In PostgreSQL, all numbers are signed, so this is trivial. However, strings are not signed (duh!)
    
    Specified by:
    
    isSigned in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2...
    
    Returns:
    
    true if so
    
    Throws:
    
    SQLException - if a database access error occurs
  - getColumnDisplaySize
```
public int getColumnDisplaySize(int column)
                         throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Indicates the designated column's normal maximum width in characters.
    
    Specified by:
    
    getColumnDisplaySize in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    the normal maximum number of characters allowed as the width of the designated column
    
    Throws:
    
    SQLException - if a database access error occurs
  - getColumnLabel
```
public String getColumnLabel(int column)
                      throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Gets the designated column's suggested title for use in printouts and displays. The suggested title is usually specified by the SQL AS clause. If a SQL AS is not specified, the value returned from getColumnLabel will be the same as the value returned by the getColumnName method.
    
    Specified by:
    
    getColumnLabel in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    the suggested column title
    
    Throws:
    
    SQLException - if a database access error occurs
  - getColumnName
```
public String getColumnName(int column)
                     throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Get the designated column's name.
    
    Specified by:
    
    getColumnName in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    column name
    
    Throws:
    
    SQLException - if a database access error occurs
  - getBaseColumnName
```
public String getBaseColumnName(int column)
                         throws SQLException
```
    Description copied from interface: PGResultSetMetaData
    
    Returns the underlying column name of a query result, or "" if it is unable to be determined.
    
    Specified by:
    
    getBaseColumnName in interface PGResultSetMetaData
    
    Parameters:
    
    column - column position (1-based)
    
    Returns:
    
    underlying column name of a query result
    
    Throws:
    
    SQLException - if something wrong happens
  - getSchemaName
```
public String getSchemaName(int column)
                     throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Get the designated column's table's schema.
    
    Specified by:
    
    getSchemaName in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    schema name or "" if not applicable
    
    Throws:
    
    SQLException - if a database access error occurs
  - getBaseSchemaName
```
public String getBaseSchemaName(int column)
                         throws SQLException
```
    Description copied from interface: PGResultSetMetaData
    
    Returns the underlying schema name of query result, or "" if it is unable to be determined.
    
    Specified by:
    
    getBaseSchemaName in interface PGResultSetMetaData
    
    Parameters:
    
    column - column position (1-based)
    
    Returns:
    
    underlying schema name of query result
    
    Throws:
    
    SQLException - if something wrong happens
  - getPrecision
```
public int getPrecision(int column)
                 throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Get the designated column's specified column size. For numeric data, this is the maximum precision. For character data, this is the length in characters. For datetime datatypes, this is the length in characters of the String representation (assuming the maximum allowed precision of the fractional seconds component). For binary data, this is the length in bytes. For the ROWID datatype, this is the length in bytes. 0 is returned for data types where the column size is not applicable.
    
    Specified by:
    
    getPrecision in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    precision
    
    Throws:
    
    SQLException - if a database access error occurs
  - getScale
```
public int getScale(int column)
             throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Gets the designated column's number of digits to right of the decimal point. 0 is returned for data types where the scale is not applicable.
    
    Specified by:
    
    getScale in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    scale
    
    Throws:
    
    SQLException - if a database access error occurs
  - getTableName
```
public String getTableName(int column)
                    throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Gets the designated column's table name.
    
    Specified by:
    
    getTableName in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    table name or "" if not applicable
    
    Throws:
    
    SQLException - if a database access error occurs
  - getBaseTableName
```
public String getBaseTableName(int column)
                        throws SQLException
```
    Description copied from interface: PGResultSetMetaData
    
    Returns the underlying table name of query result, or "" if it is unable to be determined.
    
    Specified by:
    
    getBaseTableName in interface PGResultSetMetaData
    
    Parameters:
    
    column - column position (1-based)
    
    Returns:
    
    underlying table name of query result
    
    Throws:
    
    SQLException - if something wrong happens
  - getCatalogName
```
public String getCatalogName(int column)
                      throws SQLException
```
    Gets the designated column's table's catalog name.
    As with getSchemaName(), we can say that if getTableName() returns n/a, then we can too - otherwise, we need to work on it.
    
    Specified by:
    
    getCatalogName in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2...
    
    Returns:
    
    catalog name, or "" if not applicable
    
    Throws:
    
    SQLException - if a database access error occurs
  - getColumnType
```
public int getColumnType(int column)
                  throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Retrieves the designated column's SQL type.
    
    Specified by:
    
    getColumnType in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    SQL type from java.sql.Types
    
    Throws:
    
    SQLException - if a database access error occurs
    
    See Also:
    
    Types
  - getFormat
```
public int getFormat(int column)
              throws SQLException
```
    Description copied from interface: PGResultSetMetaData
    
    Is a column Text or Binary?
    
    Specified by:
    
    getFormat in interface PGResultSetMetaData
    
    Parameters:
    
    column - column position (1-based)
    
    Returns:
    
    0 if column data foramt is TEXT, or 1 if BINARY
    
    Throws:
    
    SQLException - if something wrong happens
    
    See Also:
    
    Field.BINARY_FORMAT, Field.TEXT_FORMAT
  - getColumnTypeName
```
public String getColumnTypeName(int column)
                         throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Retrieves the designated column's database-specific type name.
    
    Specified by:
    
    getColumnTypeName in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    type name used by the database. If the column type is a user-defined type, then a fully-qualified type name is returned.
    
    Throws:
    
    SQLException - if a database access error occurs
  - isReadOnly
```
public boolean isReadOnly(int column)
                   throws SQLException
```
    Indicates whether the designated column is definitely not writable.
    In reality, we would have to check the GRANT/REVOKE stuff for this to be effective, and I haven't really looked into that yet, so this will get re-visited.
    
    Specified by:
    
    isReadOnly in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, etc.*
    
    Returns:
    
    true if so*
    
    Throws:
    
    SQLException - if a database access error occurs
  - isWritable
```
public boolean isWritable(int column)
                   throws SQLException
```
    Indicates whether it is possible for a write on the designated column to succeed.
    In reality have to check the GRANT/REVOKE stuff, which I haven't worked with as yet. However, if it isn't ReadOnly, then it is obviously writable.
    
    Specified by:
    
    isWritable in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, etc.
    
    Returns:
    
    true if so
    
    Throws:
    
    SQLException - if a database access error occurs
  - isDefinitelyWritable
```
public boolean isDefinitelyWritable(int column)
                             throws SQLException
```
    Indicates whether a write on the designated column will definitely succeed.
    Hmmm...this is a bad one, since the two preceding functions have not been really defined. I cannot tell is the short answer. I thus return isWritable() just to give us an idea.
    
    Specified by:
    
    isDefinitelyWritable in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, etc..
    
    Returns:
    
    true if so
    
    Throws:
    
    SQLException - if a database access error occurs
  - getField
```
protected Field getField(int columnIndex)
                  throws SQLException
```
    For several routines in this package, we need to convert a columnIndex into a Field[] descriptor. Rather than do the same code several times, here it is.
    
    Parameters:
    
    columnIndex - the first column is 1, the second is 2...
    
    Returns:
    
    the Field description
    
    Throws:
    
    SQLException - if a database access error occurs
  - getPGType
```
protected String getPGType(int columnIndex)
                    throws SQLException
```
    Throws:
    
    SQLException
  - getSQLType
```
protected int getSQLType(int columnIndex)
                  throws SQLException
```
    Throws:
    
    SQLException
  - getColumnClassName
```
public String getColumnClassName(int column)
                          throws SQLException
```
    Description copied from interface: java.sql.ResultSetMetaData
    
    Returns the fully-qualified name of the Java class whose instances are manufactured if the method ResultSet.getObject is called to retrieve a value from the column. ResultSet.getObject may return a subclass of the class returned by this method.
    
    Specified by:
    
    getColumnClassName in interface ResultSetMetaData
    
    Parameters:
    
    column - the first column is 1, the second is 2, ...
    
    Returns:
    
    the fully-qualified name of the class in the Java programming language that would be used by the method ResultSet.getObject to retrieve the value in the specified column. This is the class name used for custom mapping.
    
    Throws:
    
    SQLException - if a database access error occurs
  - isWrapperFor
```
public boolean isWrapperFor(Class<?> iface)
                     throws SQLException
```
    Description copied from interface: java.sql.Wrapper
    
    Returns true if this either implements the interface argument or is directly or indirectly a wrapper for an object that does. Returns false otherwise. If this implements the interface then return true, else if this is a wrapper then return the result of recursively calling isWrapperFor on the wrapped object. If this does not implement the interface and is not a wrapper, return false. This method should be implemented as a low-cost operation compared to unwrap so that callers can use this method to avoid expensive unwrap calls that may fail. If this method returns true then calling unwrap with the same argument should succeed.
    
    Specified by:
    
    isWrapperFor in interface Wrapper
    
    Parameters:
    
    iface - a Class defining an interface.
    
    Returns:
    
    true if this implements the interface or directly or indirectly wraps an object that does.
    
    Throws:
    
    SQLException - if an error occurs while determining whether this is a wrapper for an object with the given interface.
  - unwrap
```
public <T> T unwrap(Class<T> iface)
             throws SQLException
```
    Description copied from interface: java.sql.Wrapper
    
    Returns an object that implements the given interface to allow access to non-standard methods, or standard methods not exposed by the proxy. If the receiver implements the interface then the result is the receiver or a proxy for the receiver. If the receiver is a wrapper and the wrapped object implements the interface then the result is the wrapped object or a proxy for the wrapped object. Otherwise return the the result of calling unwrap recursively on the wrapped object or a proxy for that result. If the receiver is not a wrapper and does not implement the interface, then an SQLException is thrown.
    
    Specified by:
    
    unwrap in interface Wrapper
    
    Type Parameters:
    
    T - the type of the class modeled by this Class object
    
    Parameters:
    
    iface - A Class defining an interface that the result must implement.
    
    Returns:
    
    an object that implements the interface. May be a proxy for the actual implementing object.
    
    Throws:
    
    SQLException - If no object found that implements the interface

Class PgResultSetMetaData

Field Summary

Fields inherited from interface java.sql.ResultSetMetaData

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

connection

fields

Constructor Detail

PgResultSetMetaData

Method Detail

getColumnCount

isAutoIncrement

isCaseSensitive

isSearchable

isCurrency

isNullable

isSigned

getColumnDisplaySize

getColumnLabel

getColumnName

getBaseColumnName

getSchemaName

getBaseSchemaName

getPrecision

getScale

getTableName

getBaseTableName

getCatalogName

getColumnType

getFormat

getColumnTypeName

isReadOnly

isWritable

isDefinitelyWritable

getField

getPGType

getSQLType

getColumnClassName

isWrapperFor

unwrap