Question: What are triggers used for in SQL?

Triggers are the SQL codes that are automatically executed in response to certain events on a particular table. These are used to maintain the integrity of the data. A trigger in SQL works similar to a real-world trigger. For example, when the gun trigger is pulled a bullet is fired.

What are the usage of triggers?

Uses for triggers

  • Enforce business rules.
  • Validate input data.
  • Generate a unique value for a newly inserted row on a different file (surrogate function)
  • Write to other files for audit trail purposes.
  • Query from other files for cross-referencing purposes.

Should I use SQL triggers?

Triggers can be a good choice if there is an external tool that access and inserts data to your database and you cannot access to code, but you need to add some functionality on insert, delete and update clauses.

What are trigger concepts?

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.

What is a trigger in SQL with example?

A SQL trigger is a database object which fires when an event occurs in a database. We can execute a SQL query that will “do something” in a database when a change occurs on a database table such as a record is inserted or updated or deleted. For example, a trigger can be set on a record insert in a database table.

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Is it good practice to use triggers?

Using remote queries in triggers is a bad practice. Distributed queries have detrimental effects on performance and you should avoid this practice if possible.

Why you shouldn’t use triggers?

They are also the best place for auditing unless you don’t want to capture all changes to the database (which is the problem of auditing from the application). Triggers can cause performance issues if not written carefully and not enough developers are knowledgeable enough to write them well.

Do SQL triggers affect performance?

Yes, a table with a trigger will not perform as well as it would without it.

How database trigger is applied?

A database trigger is special stored procedure that is run when specific actions occur within a database. Most triggers are defined to run when changes are made to a table’s data. Triggers can be defined to run instead of or after DML (Data Manipulation Language) actions such as INSERT, UPDATE, and DELETE.

What is trigger and its types?

A trigger defines a set of actions that are performed in response to an insert, update, or delete operation on a specified table. When such an SQL operation is executed, the trigger is said to have been activated. Triggers are optional and are defined using the CREATE TRIGGER statement.

How do I view triggers in SQL?

To view database level triggers, Login to the server using SQL Server management studio and navigate to the database. Expand the database and navigate to Programmability -> Database Triggers. To view triggers at the server level, Login to Server using SSMS and navigate to Server Objects and then Triggers folder.

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Can we fire a trigger manually?

Triggers cannot be manually executed by the user. There is no chance for triggers to receive parameters.