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Oracle After Trigger


This statement specifies that Oracle will fire this trigger AFTER the INSERT/UPDATE or DELETE operation is executed.

Syntax

  1. CREATE [ OR REPLACE ] TRIGGER trigger_name
  2. AFTER INSERT or UPDATE or DELETE
  3.  ON table_name
  4.   [ FOR EACH ROW ]
  5. DECLARE
  6.    — variable declarations
  7. BEGIN
  8.    — trigger code
  9. EXCEPTION
  10.    WHEN …
  11.    — exception handling
  12. END;

Parameters

OR REPLACE: It is an optional parameter. It is used to re-create the trigger if it already exists. It facilitates you to change the trigger definition without using a DROP TRIGGER statement.

trigger_name: It specifies the name of the trigger that you want to create.

AFTER INSERT or UPDATE or DELETE: It specifies that the trigger will be fired after the INSERT or UPDATE or DELETE operation is executed.

table_name: It specifies the name of the table on which trigger operation is being performed.

Limitations

  • AFTER trigger cannot be created on a view.
  • You cannot update the OLD values.
  • You can only update the NEW values.

Oracle AFTER Trigger Example

Consider, you have a “suppliers” table with the following parameters.

  1. CREATE TABLE  “SUPPLIERS”
  2.    (    “SUPPLIER_ID” NUMBER,
  3.     “SUPPLIER_NAME” VARCHAR2(4000),
  4.     “SUPPLIER_ADDRESS” VARCHAR2(4000)
  5.    )
  6. /

You can use the following CREATE TRIGGER query to create a AFTER INSERT or UPDATE or DELETE Trigger:

  1. CREATE OR REPLACE TRIGGER  “SUPPLIERS_T2”
  2. AFTER
  3. insert or update or delete on “SUPPLIERS”
  4. for each row
  5. begin
  6. when the person performs insert/update/delete operations into the table.
  7. end;
  8. /
  9. ALTER TRIGGER  “SUPPLIERS_T2” ENABLE
  10. /

Here the trigger name is “SUPPLIERS_T2” and it is fired AFTER the insert or update or delete operation is executed on the table “suppliers”.

aftertrigger

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