Why are use triggers in the SQL Server Database?
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18-Jul-2024
Updated on 18-Jul-2024
Ashutosh Kumar Verma
18-Jul-2024SQL Server Trigger
Triggers in a database are special stored procedures that are automatically executed or fired in response to certain events in a table or view. It is used to enforce business rules, ensure data integrity, and automate business based on data transformation.
Key Uses of Triggers
Data Validation and Enforcement
Verify that a value in a column meets certain criteria before allowing it to be
insert
orupdat
. For example, below created trigger is prevented from inserting the negative value into the Salary column,Maintain History
Triggers are also used to automatically maintain a history of records that are deleted from tables.
the below trigger is fires automatically when someone deleted the record from
Employees
table and insert the deleted records intoEmployees_History
tableTypes of Triggers
BEFORE Triggers- Perform before the triggering event (INSERT, UPDATE, DELETE). Useful for validating or editing data before commissioning.
AFTER Triggers- Perform after the triggering event has occurred. Useful for actions like logging or updating linked tables.
INSTEAD OF Triggers- Replace trigger events with intentional actions. Useful for custom tasks.
Benefits of Using Triggers
Automation- The rules are enforced and tasks are performed without the need for manual intervention.
Consistency- Ensure data integrity and business rules are applied consistently throughout the database.
Auditing- Provide a built-in tool to track changes in data to monitor compliance and correct deficiencies.
Also, Read: What are SQL Stored Procedures in the Database?