A program in a database that gets called each time a row in a table is INSERTED UPDATED or DELETED. Triggers allow you to check that any changes are correct or to fill in missing information before it is commited. Triggers are normally written in PL/SQL or Java
A Trigger is a PL/SQL block that executes whenever a particular event takes place.events in database like Insert Update Delete and combination of these three will cause the trigger to execute.Trigger is a technique to maintain integrity constraints
Trigger is an SQL procedure that initates an action when an event(inser/delete/update) occurs. They are stored and manageed by DBMS.A trigger cannot be called or executed:the DBMS automatically fires the trigger as a result of a data modification to the associated table. Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion. Each trigger is attached to a single specific table in the database.
A database trigger is procedural code that is automatically executed in response to certain events on a particular table in a database. Triggers can restrict access to specific data perform logging or audit data modifications.