What is an trigger and how will create, disable, compile, rename

A trigger is a PL/SQL block associated with a table, view or a database scheme. Is executed whenever an event occurs.
Types of triggers:
– triggers for application
– triggers at the database level

CREATE OR REPLACE TRIGGER trigger_name

{BEFORE | AFTER | INSTEAD OF} 

{INSERT | UPDATE | DELETE} 

 [OF column_name] 

 ON table_name 

 [REFERENCING OLD AS old NEW AS new] 

 [FOR EACH ROW] 

 WHEN (condition)  

 BEGIN 

 --- pl/sql code  

 END; 

ALTER TRIGGER trigger_name ENABLE;

ALTER TRIGGER trigger_name DISABLE;

ALTER TRIGGER trigger_name COMPILE;

ALTER TRIGGER trigger_name RENAME TO new_trigger_name;

ALTER TABLE table_name DISABLE ALL TRIGGERS;

ALTER TABLE table_name ENABLE ALL TRIGGERS;