Triggers are stored programs, which are automatically executed or fired when some events occur. Triggers are, in fact, written to be executed in response to any of the following events −
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A database manipulation (DML) statement (DELETE, INSERT, or UPDATE)
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A database definition (DDL) statement (CREATE, ALTER, or DROP).
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A database operation (SERVERERROR, LOGON, LOGOFF, STARTUP, or SHUTDOWN).
Triggers can be defined on the table, view, schema, or database with which the event is associated.
