Trigger updating column oracle
After triggers are designed for post processing after requested change was performed.
After triggers can write data into tables and unlike some SQLite only supports row-level triggers, not statement-level triggers.
In addition to triggers that fire when data is modified, Oracle 10g supports triggers that fire when schema level objects (that is, tables) are modified and when user logon or logoff events occur.
These trigger types are referred to as "Schema-level triggers". Performing conditional actions in triggers (or testing data following modification) is done through accessing the temporary Inserted and Deleted tables. The following functionality in SQL:2003 was previously not implemented in Postgre SQL: Firebird supports multiple row-level, BEFORE or AFTER, INSERT, UPDATE, DELETE (or any combination of thereof) triggers per table, where they are always "in addition to" the default table changes, and the order of the triggers relative to each other can be specified where it would otherwise be ambiguous (POSITION clause.) Triggers may also exist on views, where they are always "instead of" triggers, replacing the default updatable view logic.: PARENT.dname); END; / set serveroutput on UPDATE TABLE ( SELECT FROM dept_or p WHERE deptno = 10) SET ename = LOWER(ename); ON ov_empdept FOR EACH ROW BEGIN INSERT INTO emp (empno, ename, job, mgr, hiredate, sal, comm, deptno) VALUES (: NEW.empno, : NEW.ename, : NEW.job, : NEW.mgr, : NEW.hiredate, : NEW.sal, : NEW.comm, : deptno); INSERT INTO dept (deptno, dname, location) VALUES (: deptno, : dname, : location); END ioft_ov_empdept; / INSERT INTO ov_empdept (empno, ename, dept) VALUES (4, 'D.
But, you may be wondering, why are triggers so hated? They can be hundreds of lines long and contain convoluted conditions.Does it mean delete all employees that are in department LCR?