ALOCK TABLE emp IN SHARE MODE;
BLOCK TABLE emp IN EXCLUSIVE MODE;
CUPDATE emp SET sal=sal*1.2 WHERE job=ANAGER?UPDATE emp SET sal=sal*1.2 WHERE job=?ANAGER?
DINSERT INTO emp(empno,ename) VALUES (1289,’Harry’);
ESELECT ename FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno