Why we create trigger in stored procedure in sql

Question

I want to know why we create trigger in SQL.Please dont post a link just clarify me in words what is exactly need of triggers to create in a database.

Jignesh Kumar · Answer

Hi Priyanks, Trigger is basically execute automatically from SQL server if you have created trigger for perticular table. You can create trigger for table for insert, update and delete. It means when you do any operation like insert, update or delete. Trigger will automatically call by SQL server and it execute your logic which you write in trigger. There are two table which you should know before working with trigger, Inserted Deleted These table are called magic table in SQL server and it is managed by SQL internally. https://www.c-sharpcorner.com/UploadFile/93126e/what-are-the-magic-tables-used-by-triggers-in-sql-server/ Please find link to understand more on trigger, It will create your doubt. https://www.mssqltips.com/sqlservertip/4055/create-a-simple-sql-server-trigger-to-build-an-audit-trail/

Piyush Pansuriya · Answer

Trigger: A trigger is a stored procedure in database which automatically invokes whenever a special event in the database occurs. For example, a trigger can be invoked when a row is inserted into a specified table or when certain table columns are being updated. BEFORE and AFTER of Trigger: BEFORE triggers run the trigger action before the triggering statement is run. AFTER triggers run the trigger action after the triggering statement is run.

Navneet Arora · Answer

If you want to enforce that your data follow particular rules. In simple cases (like uniqueness of a column’s values in a table, non-null, only a list of values can be taken) this can be done by a constraint. However, if those conditions are more complicated, you have to write procedural code that makes sure that the condition is fulfilled whenever a record is inserted, updated, or removed. You should use triggers only to ensure data consistency, not as part of your application code you stuff into the database. And you should look for ways to avoid them if at all possible. It is like pouring glue into an engine, you will often influence performance negatively and unpredictably.

Rajeev Kumar · Answer

A trigger is a special type of stored procedure that automatically runs when an event occurs in the database server . DML triggers run when a user tries to modify data through a data manipulation language (DML) event. DML events are INSERT, UPDATE, or DELETE statements on a table or view