SQL adaptation guide for PostgreSQL 9.x / BDL programming |
Informix® allows positioned UPDATEs and DELETEs with the "WHERE CURRENT OF cursor" clause, if the cursor has been DECLARED with a SELECT ... FOR UPDATE statement.
UPDATE/DELETE ... WHERE CURRENT OF is supported by PostgreSQL with server-side cursors created with a DECLARE statement.
UPDATE/DELETE ... WHERE CURRENT OF instructions are executed as is. Since SELECT FOR UPDATE statements are now executed with a server cursor by using a DECLARE PostgreSQL statement, native positioned update/delete takes place.