Package org.postgresql.jdbc

Class PgResultSetMetaData

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	Description
protected final BaseConnection	connection
protected final Field[]	fields

Fields inherited from interface java.sql.ResultSetMetaData

columnNoNulls, columnNullable, columnNullableUnknown

Constructor Summary

Constructors

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

Method Summary

Modifier and Type	Method	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)
String	getColumnClassName(int column)
int	getColumnCount()
int	getColumnDisplaySize(int column)
String	getColumnLabel(int column)
String	getColumnName(int column)
int	getColumnType(int column)
String	getColumnTypeName(int column)
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 @Nullable String	getPGType(int columnIndex)
int	getPrecision(int column)
int	getScale(int column)
String	getSchemaName(int column)
protected int	getSQLType(int columnIndex)
String	getTableName(int column)
boolean	isAutoIncrement(int column)
boolean	isCaseSensitive(int column)
boolean	isCurrency(int column)
boolean	isDefinitelyWritable(int column)
int	isNullable(int column)
boolean	isReadOnly(int column)
boolean	isSearchable(int column)
boolean	isSigned(int column)
boolean	isWrapperFor(Class<?> iface)
boolean	isWritable(int column)
<T> T	unwrap(Class<T> iface)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

connection

protected final BaseConnection connection

fields

protected final Field[] fields

Constructor Details

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 Details

getColumnCount

public int getColumnCount()
                   throws SQLException

Specified by:

getColumnCount in interface ResultSetMetaData

Throws:

SQLException

isAutoIncrement

public boolean isAutoIncrement(int column)
                        throws SQLException

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

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

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

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

Specified by:

isNullable in interface ResultSetMetaData

Throws:

SQLException

isSigned

public boolean isSigned(int column)
                 throws SQLException

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

Specified by:

getColumnDisplaySize in interface ResultSetMetaData

Throws:

SQLException

getColumnLabel

public String getColumnLabel(int column)
                      throws SQLException

Specified by:

getColumnLabel in interface ResultSetMetaData

Throws:

SQLException

getColumnName

public String getColumnName(int column)
                     throws SQLException

Specified by:

getColumnName in interface ResultSetMetaData

Throws:

SQLException

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

Specified by:

getSchemaName in interface ResultSetMetaData

Throws:

SQLException

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

Specified by:

getPrecision in interface ResultSetMetaData

Throws:

SQLException

getScale

public int getScale(int column)
             throws SQLException

Specified by:

getScale in interface ResultSetMetaData

Throws:

SQLException

getTableName

public String getTableName(int column)
                    throws SQLException

Specified by:

getTableName in interface ResultSetMetaData

Throws:

SQLException

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

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

Specified by:

getColumnType in interface ResultSetMetaData

Throws:

SQLException

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 format 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

Specified by:

getColumnTypeName in interface ResultSetMetaData

Throws:

SQLException

isReadOnly

public boolean isReadOnly(int column)
                   throws SQLException

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

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

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 @Nullable 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

Specified by:

getColumnClassName in interface ResultSetMetaData

Throws:

SQLException

isWrapperFor

public boolean isWrapperFor(Class<?> iface)
                     throws SQLException

Specified by:

isWrapperFor in interface Wrapper

Throws:

SQLException

unwrap

public <T> T unwrap(Class<T> iface)
             throws SQLException

Specified by:

unwrap in interface Wrapper

Throws:

SQLException