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Is it possible to enable or disable database trigger?
The trigger still exists as an object in the current database. Triggers can be re-enabled by using ENABLE TRIGGER. DML triggers defined on tables can be also be disabled or enabled by using ALTER TABLE.
How do I disable triggers in postgresql?
To disable a trigger, you use the ALTER TABLE DISABLE TRIGGER statement:
- ALTER TABLE table_name DISABLE TRIGGER trigger_name | ALL.
- ALTER TABLE employees DISABLE TRIGGER log_last_name_changes;
- ALTER TABLE employees DISABLE TRIGGER ALL;
Can we use triggers for DML operations?
DML triggers can be used to enforce business rules and data integrity, query other tables, and include complex Transact-SQL statements. The trigger and the statement that fires it are treated as a single transaction, which can be rolled back from within the trigger.
What are types of DML triggers?
There are two types of DML triggers: AFTER or FOR trigger and INSTEAD OF trigger. The AFTER trigger will be fired and executed after performing the INSERT, UPDATE or DELETE action that fires it successfully. Also, any referential cascade actions and constraint checks should succeed before firing the trigger.
What is a DML trigger in data manipulation language?
DML triggers is a special type of stored procedure that automatically takes effect when a data manipulation language (DML) event takes place that affects the table or view defined in the trigger.
How are Dml triggers used in SQL Server?
Unlike CHECK constraints, DML triggers can reference columns in other tables. For example, a trigger can use a SELECT from another table to compare to the inserted or updated data and to perform additional actions, such as modify the data or display a user-defined error message.
When to check constraints on DML trigger table?
If constraints exist on the trigger table, they are checked after the INSTEAD OF trigger execution but prior to the AFTER trigger execution. If the constraints are violated, the INSTEAD OF trigger actions are rolled back and the AFTER trigger is not executed.
How are Dml events used in SQL Server?
DML events include INSERT, UPDATE, or DELETE statements. DML triggers can be used to enforce business rules and data integrity, query other tables, and include complex Transact-SQL statements.