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What is disadvantage of trigger?
It is easy to view table relationships , constraints, indexes, stored procedure in database but triggers are difficult to view. Triggers execute invisible to client-application application. They are not visible or can be traced in debugging code.
What is instead of update trigger?
Instead Of Update Triggers These triggers are executed instead of any of the Insert, Update or Delete operations. For example consider an Instead of Trigger for Update operation, whenever an Update is performed the Trigger will be executed first and if the Trigger updates record then only the record will be updated.
What is the benefit of trigger?
These benefits are: Faster application development. Because the database stores triggers, you do not have to code the trigger actions into each database application. Define a trigger once and then reuse it for any application that uses the database. Easier maintenance.
When to use triggers in INSERT UPDATE DELETE?
Triggers can be set to run as a part of any combination of INSERT, UPDATE, and DELETE statements. Often the actions undertaken by the trigger only need to happen in certain scenarios where specific columns have been affected.
When to use trigger to stop insert or update in MySQL?
The error message is as follows: If you insert records between 1 and 5, there won’t be any error. It does not prevent insertion of records since as discussed above our trigger is created to insert records between 1 and 5. The query to insert record is as follows: Display all records from the table using select statement.
How does a trigger work in SQL Server?
Using UPDATE and COLUMNS_UPDATED for SQL Server Triggers. SQL Server provides 2 functions to help determine which columns were involved in a statement that caused a trigger to fire. They are UPDATE and COLUMNS_UPDATED. UPDATE accepts a single parameter which is a column name for the underlying table.
How to prevent update when flag value is 1?
[Tmp] FOR UPDATE AS SET NOCOUNT ON IF EXISTS (SELECT NULL FROM dbo.Tmp t JOIN deleted i ON t.Id=i.Id AND i.Flag=1) BEGIN RAISERROR (‘You can not update when Flag value is 1’, 16, 1) ROLLBACK TRAN SET NOCOUNT OFF RETURN END SET NOCOUNT OFF