| SQL adaptation guide For Oracle MySQL 5.x / BDL programming | |
Informix® closes opened cursors automatically when a transaction ends unless the WITH HOLD option is used in the DECLARE instruction. In MySQL, opened cursors using SELECT statements without a FOR UPDATE clause are not closed when a transaction ends. Actually, all MySQL cursors are 'WITH HOLD' cursors unless the FOR UPDATE clause is used in the SELECT statement.
Cursors declared FOR UPDATE and using the WITH HOLD option cannot be supported with MySQL because FOR UPDATE cursors are automatically closed by MySQL 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 MySQL automatically closes FOR UPDATE cursors when the transaction ends, opening cursors declared FOR UPDATE and WITH HOLD option results in an SQL error; in the same conditions, this does not normally appear with Informix. Review the program logic in order to find another way to set locks.