Syntax

1. <lock_statement> ::=
     LOCK [(WAIT)|(NOWAIT)] <lock_spec> IN SHARE MODE
   | LOCK [(WAIT)|(NOWAIT)] <lock_spec> IN EXCLUSIVE MODE
   | LOCK [(WAIT)|(NOWAIT)] <lock_spec> IN SHARE MODE <lock_spec> IN EXCLUSIVE MODE
   | LOCK [(WAIT)|(NOWAIT)] <row_spec>... OPTIMISTIC