What is Trigger in Oracle?

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 "It is one of the most important questions for an interview. It is useful for the fresher, Intermediate and experienced candidates."

DEFINITION:



It is invoked automatically by the oracle engine for the specific event occurs. It is stored in the database as named plsql unit for the specific event occurs and invoked repeatedly. It is the stored programs or procedure which is automatically executed or fired for the certain specific events. It can be defined on the table,view,schema and database on which an event is associated. It is used in DDL statement, DML statement and database operation.

DDL: Create, Alter and drop.

DML: Insert, Update and Delete

Database operation: LOGON, LOGOFF, STARTUP,

SHUTDOWN AND SERVER ERROR.

It is called as block structures or pre-defined programs which is developed by the developers for the particular task.

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