DB2 Version 9.7 for Linux, UNIX, and Windows

Examples of ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnLabel values

For the IBM® Data Server Driver for JDBC and SQLJ version 4.0 and later, the default behavior of ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnLabel differs from the default behavior for earlier JDBC drivers. You can use the useJDBC4ColumnNameAndLabelSemantics property to change this behavior.

The following examples show the values that are returned for IBM Data Server Driver for JDBC and SQLJ Version 4.0, and for previous JDBC drivers, when the useJDBC4ColumnNameAndLabelSemantics property is not set.

All queries use a table that is defined like this:

CREATE TABLE MYTABLE(INTCOL INT)

Example: The following query contains an AS CLAUSE, which defines a label for a column in the result set:

SELECT MYCOL AS MYLABEL FROM MYTABLE

The following table lists the ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnName values that are returned for the query:

Table 1. ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnName before and after IBM Data Server Driver for JDBC and SQLJ Version 4.0 for a query with an AS CLAUSE
Target data source	Behavior before IBM Data Server Driver for JDBC and SQLJ Version 4.0		Behavior for IBM Data Server Driver for JDBC and SQLJ Version 4.0 and later
Target data source	getColumnName value	getColumnLabel value	getColumnName value	getColumnLabel value
DB2® for Linux, UNIX, and Windows	MYLABEL	MYLABEL	MYCOL	MYLABEL
IBM Informix®	MYLABEL	MYLABEL	MYCOL	MYLABEL
DB2 for z/OS® Version 8 or later, and DB2 UDB for iSeries® V5R3 and later	MYLABEL	MYLABEL	MYCOL	MYLABEL
DB2 for z/OS Version 7, and DB2 UDB for iSeries V5R2	MYLABEL	MYLABEL	MYLABEL	MYLABEL

Example: The following query contains no AS clause:

SELECT MYCOL FROM MYTABLE

The ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnLabel methods on the query return MYCOL, regardless of the target data source.

Example: On a DB2 for z/OS or DB2 for i data source, a LABEL ON statement is used to define a label for a column:

LABEL ON COLUMN MYTABLE.MYCOL IS 'LABELONCOL'

The following query contains an AS CLAUSE, which defines a label for a column in the ResultSet:

SELECT MYCOL AS MYLABEL FROM MYTABLE

The following table lists the ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnName values that are returned for the query.

Table 2. ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnName before and after IBM Data Server Driver for JDBC and SQLJ Version 4.0 for a table column with a LABEL ON statement in a query with an AS CLAUSE
Target data source	Behavior before IBM Data Server Driver for JDBC and SQLJ Version 4.0		Behavior for IBM Data Server Driver for JDBC and SQLJ Version 4.0 and later
Target data source	getColumnName value	getColumnLabel value	getColumnName value	getColumnLabel value
DB2 for z/OS Version 8 or later, and DB2 UDB for iSeries V5R3 and later	MYLABEL	LABELONCOL	MYCOL	MYLABEL
DB2 for z/OS Version 7, and DB2 UDB for iSeries V5R2	MYLABEL	LABELONCOL	MYCOL	LABELONCOL

Example: On a DB2 for z/OS or DB2 for i data source, a LABEL ON statement is used to define a label for a column:

LABEL ON COLUMN MYTABLE.MYCOL IS 'LABELONCOL'

The following query contains no AS CLAUSE:

SELECT MYCOL FROM MYTABLE

The following table lists the ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnName values that are returned for the query.

Table 3. ResultSetMetaData.getColumnName and ResultSetMetaData.getColumnName before and after IBM Data Server Driver for JDBC and SQLJ Version 4.0 for a table column with a LABEL ON statement in a query with no AS CLAUSE
Target data source	Behavior before IBM Data Server Driver for JDBC and SQLJ Version 4.0		Behavior for IBM Data Server Driver for JDBC and SQLJ Version 4.0
Target data source	getColumnName value	getColumnLabel value	getColumnName value	getColumnLabel value
DB2 for z/OS Version 8 or later, and DB2 UDB for i5/OS™ V5R3 and later	MYCOL	LABELONCOL	MYCOL	MYCOL
DB2 for z/OS Version 7, and DB2 UDB for i5/OS V5R2	MYCOL	LABELONCOL	MYLABEL	LABELONCOL