Differentiating Table Names

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In SQL, using multiple databases in transactions sometimes requires extra precautions to ensure intended behavior. When two or more databases have tables that share the same name, a database handle must be prefixed to those table names to differentiate them from one another in transactions.

A table name differentiated by a database handle takes the form:

handle.table

For example, the following cursor declaration accesses an EMPLOYEE table in TEST, and another EMPLOYEE table in EMP. TEST and EMP are used as prefixes to indicate which EMPLOYEE table should be referenced:

. . .
EXEC SQL
DECLARE IDMATCH CURSOR FOR
SELECT TESTNO INTO :matchid FROM TEST.EMPLOYEE
WHERE (SELECT EMPNO FROM EMP.EMPLOYEE WHERE EMPNO = TESTNO);
. . .

Note:
DSQL does not support access to multiple databases in a single statement.

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