Difference between Trigger and Procedure in DBMS
1. Procedures: A procedure is a combination of SQL statements written to perform specified tasks. It helps in code re-usability and saves time and lines of code.
Advantages of Procedures:
- A Stored Procedure can be used as modular programming, which means that it can be created once, stored, and called multiple times as needed. This allows for speedier execution.
- Reduces network traffic
- Improving data security
- Easy to maintain because the stored procedure scripts are all in one place and hence, it is easy to update and track dependencies when schema changes occur.
- Testing can be carried out independent of the application.
2. Triggers: A trigger is a special kind of procedure that executes only when some triggering event such as INSERT, UPDATE, or DELETE operations occur in a table.
Advantages of Triggers:
- Protection of data
- Inhibits transactions that are not valid
- It also keeps the different tables in sync.
- Referential integrity is enforced with the use of triggers.
- Triggers can also be used in event logging and auditing.
Difference between Triggers and Procedures:
|1.||Basics||A Trigger is implicitly invoked whenever any event such as INSERT, DELETE, or UPDATE occurs in a TABLE.||A Procedure is explicitly called by the user/application using statements or commands such as exec, EXECUTE, or simply procedure name|
|2.||Action||When an event occurs, a trigger helps to execute an action automatically.||A procedure helps to perform a specified task when it is invoked.|
|3.||Define/ call||Only nesting of triggers can be achieved in a table. We cannot define/call a trigger inside another trigger.||We can define/call procedures inside another procedure.|
|4.||Syntax||In a database, the syntax to define a trigger: CREATE TRIGGER TRIGGER_NAME||In a database, the syntax to define a procedure: CREATE PROCEDURE PROCEDURE_NAME|
|5.||Transaction statements||Transaction statements such as COMMIT, ROLLBACK, and SAVEPOINT are not allowed in triggers.||All transaction statements such as COMMIT and ROLLBACK are allowed in procedures.|
|6.||Usage||Triggers are used to maintain referential integrity by keeping a record of activities performed on the table.||Procedures are used to perform tasks defined or specified by the users.|
|7.||Return value||We cannot return values in a trigger. Also, as an input, we cannot pass values as a parameter.||We can return 0 to n values. However, we can pass values as parameters.|