Learning MariaDB Triggers

1. Does MariaDB have triggers?
2. How do I use trigger in MariaDB?
3. How the triggers will execute if two or more triggers?
4. Which table Cannot have a trigger?
5. Which event occurs when a database trigger fails?
6. What is Definer in MySQL trigger?
7. How do I alter a trigger in MySQL?
8. How do you show triggers?
9. How do I drop all triggers?
10. Can we call a trigger inside a trigger?
11. Can a trigger fire another trigger?
12. How do you call a trigger?

Does MariaDB have triggers?

MySQL/MariaDB triggers are stored programs associated with a table in a database, and used to automatically perform some actions when an INSERT , DELETE or UPDATE event is performed on the table. A trigger can be set to perform an action either before or after the event it is associated to.

How do I use trigger in MariaDB?

Introduction to MariaDB create trigger statement

In this syntax: First, specify the name of the trigger that you want to create after the create trigger keywords. The trigger name must be distinct within a database. Second, specify the action time that the trigger is invoked.

How the triggers will execute if two or more triggers?

Sometimes the business logic dictates that we need to define two triggers on a table that must fire in a specific order on the same table action. For example when we insert rows in a table (INSERT statement) two triggers must fire and the second must fire after the first one for our logic to be implemented correctly.

Which table Cannot have a trigger?

Since triggers execute as part of a transaction, the following statements are not allowed in a trigger: All create commands, including create database, create table, create index, create procedure, create default, create rule, create trigger, and create view. All drop commands. alter table and alter database.

Which event occurs when a database trigger fails?

Failure of a trigger causes the statement to fail, so trigger failure also causes rollback. For nontransactional tables, such rollback cannot be done, so although the statement fails, any changes performed prior to the point of the error remain in effect.

What is Definer in MySQL trigger?

The DEFINER clause specifies the MySQL account to be used when checking access privileges at trigger activation time. If the DEFINER clause is present, the user value should be a MySQL account specified as ' user_name '@' host_name ' , CURRENT_USER , or CURRENT_USER() .

How do I alter a trigger in MySQL?

To create or alter the trigger definition using SQL Editor, type the trigger statement in the SQL Editor using standard SQL. Enter only the trigger statement, that is, the part of the CREATE TRIGGER query that is placed after the FOR EACH ROW clause. All other trigger properties are set in the Properties window.

How do you show triggers?

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.

How do I drop all triggers?

max_allowed_packet; -- select all the triggers and build the `DROP TRIGGER` SQL -- replace <your_schema> with your schema name (e.g. your database name) SELECT GROUP_CONCAT(sql_string SEPARATOR '\n') FROM ( SELECT CONCAT('DROP TRIGGER IF EXISTS `', TRIGGER_NAME, '`;') AS sql_string,'1' FROM information_schema.

Can we call a trigger inside a trigger?

Both DML and DDL triggers are nested when a trigger performs an action that initiates another trigger. These actions can initiate other triggers, and so on. DML and DDL triggers can be nested up to 32 levels. You can control whether AFTER triggers can be nested through the nested triggers server configuration option.

Can a trigger fire another trigger?

In addition to being triggered by DML and DDL operations, triggers in SQL Server can also be triggered by other triggers. This type trigger is called a nested trigger in SQL or a recursive trigger.

How do you call a trigger?

Procedure

1. Write a basic CREATE TRIGGER statement specifying the desired trigger attributes. ...
2. In the trigger action portion of the trigger you can declare SQL variables for any IN, INOUT, OUT parameters that the procedure specifies. ...
3. In the trigger action portion of the trigger add a CALL statement for the procedure.