| SQL adaptation guide for PostgreSQL 9.x / BDL programming | |
Informix® closes opened cursors automatically when a transaction ends unless the WITHHOLD option is used in the DECLARE instruction. In PostgreSQL, opened cursors using SELECT statements without a FOR UPDATE clause are not closed when a transaction ends. Actually, all PostgreSQL cursors are 'WITH HOLD' cursors unless the FOR UPDATE clause issued in the SELECT statement.
Cursors declared FOR UPDATE and using the WITH HOLD option cannot be supported with PostgreSQL because FOR UPDATE cursors are automatically closed by PostgreSQL when the transaction ends.
BDL cursors that are not declared "WITH HOLD" are automatically closed by the database interface when a COMMIT WORK or ROLLBACK WORK is performed.
Since PostgreSQL automatically closes FOR UPDATE cursors when the transaction ends, opening cursors declared FOR UPDATE and the WITH HOLD option results in an SQL error that does not normally appear with Informix under the same conditions. Review the program logic in order to find another way to set locks.