Pl sql trigger if updating


Triggers are stored programs, which are automatically executed or fired when some event occurs.

Triggers are written to be executed in response to any of the following events.

The "dml-event" can be one or more of the following.

pl sql trigger if updating-78pl sql trigger if updating-47pl sql trigger if updating-50pl sql trigger if updating-22

The CREATE TRIGGER statement has a lot of permutations, but the vast majority of the questions I'm asked relate to basic DML triggers.There are two types of triggers based on the which level it is triggered.1) Row level trigger - An event is triggered for each row upated, inserted or deleted.Trigger is invoked by Oracle engine automatically whenever a specified event occurs.Trigger is stored into database and invoked repeatedly, when specific condition match.Example 39-4 shows an example of an audit trigger procedure in CREATE TABLE emp ( empname text NOT NULL, salary integer ); CREATE TABLE emp_audit( operation char(1) NOT NULL, stamp timestamp NOT NULL, userid text NOT NULL, empname text NOT NULL, salary integer ); CREATE OR REPLACE FUNCTION process_emp_audit() RETURNS TRIGGER AS $emp_audit$ BEGIN -- -- Create a row in emp_audit to reflect the operation performed on emp, -- make use of the special variable TG_OP to work out the operation.

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