What are the components of a DML trigger?
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A DML trigger is a database trigger whose triggering event is a Data Manipulation Language (DML) statement. A DML trigger has the following components:
Trigger timing: It decides the time of the trigger's execution in relation to the triggering event. Possible values are BEFORE, AFTER, and INSTEAD OF. BEFORE specifies that the trigger body will be executed before the triggering event is executed on the associated table. AFTER specifies that the trigger body will be executed after the triggering event is executed on the associated table. INSTEAD OF specifies that the trigger body will be executed instead of the triggering event. INSTEAD OF can be specified only for views and not for tables.
Triggering event: It specifies the Data Manipulation Language (DML) statement that causes the trigger to fire. Possible values are INSERT, UPDATE, and DELETE.
Trigger type: It determines how many times the trigger body executes. Possible values are statement (default) and row (FOR EACH ROW). Statement specifies that the trigger body will be executed only once for the triggering event, regardless of the number of rows affected by the triggering event. Row specifies that the trigger body will be executed once for each row affected by the triggering event.
Trigger body: It determines the action that the trigger will perform when it is fired. The trigger body is a complete PL/SQL block or a CALL statement that calls a stored procedure.
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