What Are Triggers in SQL Server

Q

What Are Triggers in SQL Server?

✍: FYIcenter.com

A

A trigger is a special kind of stored procedure that automatically executes when an event occurs in the database server. A trigger is really an event handler. SQL Server allows users to create triggers (event handlers) for 3 types of events:

DML Event - Occurs when a DML (Data Manipulation Language) statement: INSERT, UPDATE or DELETE, is executed.
DDL Event - Occurs when a DDL (Data Definition Language) statement: CREATE, ALTER, or DROP, is executed.
Logon Event - Occurs when a user logins to the Server.

There are 3 different types of triggers (event handlers) based on the types of events they are triggered by:

DML Trigger - Executes in response to a DML event.
DDL Trigger - Executes in response to a DDL event.
Logon Trigger - Executes in response to a logon event.

⇒ Basic Features of a Trigger in SQL Server

⇐ Creating and Managing Triggers in SQL Server

⇑ Creating and Managing Triggers in SQL Server

⇑⇑ SQL Server Database Tutorials

2016-10-25, 1303🔥, 0💬

sys.triggers - Listing All Triggers in the Database in SQL Server
How To List All Triggers in the Database with sys.triggers in SQL Server? If you want to list all triggers defined in the current database, you can use the catalog view, sys.triggers, as shown in the following tutorial example: USE FyiCenterData; GO CREATE TRIGGER new_user ON fyi_users AFTER INSERT ... 2016-10-25, 1870🔥, 0💬

Creating and Managing Triggers in SQL Server
Where to find answers to frequently asked questions on Creating and Managing Triggers in SQL Server? Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team on Creating and Managing Triggers in SQL Server. Clear explanations and tutorial exercises are provid... 2016-10-25, 1456🔥, 0💬

Testing DML Triggers in SQL Server
How To Test a DML Trigger in SQL Server? To test a DML trigger defined on a table, you just need to execute several INSERT, UPDATE and DELETE statements on that table as shown in this tutorial example: USE FyiCenterData; GO INSERT INTO fyi_users (name) VALUES ('FYI Admin'); GO Records are inserted, ... 2016-10-25, 1377🔥, 0💬

Using Multiple Columns in the GROUP BY Clause in SQL Server
Can Multiple Columns Be Used in GROUP BY in SQL Server? If you want to break your output into smaller groups, you can specify multiple column names or expressions in the GROUP BY clause. Output in each group must satisfy a specific combination of the expressions listed in the GROUP BY clause. The mo... 2016-10-25, 1373🔥, 0💬

Using Group Functions in the ORDER BY Clause in SQL Server
Can Group Functions Be Used in the ORDER BY Clause in SQL Server? If the query output is aggregated as groups, you can sort the groups by using group functions in the ORDER BY clause. The following statement returns the maximum "counts" in each group, determined by a unique combination of tag and ye... 2016-10-25, 1342🔥, 0💬

Creating a Simple Table to Test Triggers in SQL Server
How To Create a Simple Table to Test Triggers in SQL Server? If you want to follow other tutorial examples included in this collection, you need to run this SQL script to create a simple table called fyi_users: USE FyiCenterData; GO DROP TABLE fyi_users; GO CREATE TABLE fyi_users ( id INTEGER IDENTI... 2016-10-25, 1315🔥, 0💬

What Are Triggers in SQL Server
What Are Triggers in SQL Server? A trigger is a special kind of stored procedure that automatically executes when an event occurs in the database server. A trigger is really an event handler. SQL Server allows users to create triggers (event handlers) for 3 types of events: DML Event - Occurs when a... 2016-10-25, 1304🔥, 0💬

"CREATE TRIGGER" - Creating a DML Trigger in SQL Server
How To Create a DML Trigger using CREATE TRIGGER Statements in SQL Server? A DML trigger is a trigger declared to handle a DML event, which occurs when an INSERT, UPDATE or DELETE statement is executed. If you want to create a DML trigger, you should use the "CREATE TRIGGER" statement in the followi... 2016-10-25, 1303🔥, 0💬

HAVING - Apply Filtering Criteria at Group Level in SQL Server
How To Apply Filtering Criteria at Group Level with The HAVING Clause in SQL Server? Let's say you have divided the query output into multiple groups with the GROUP BY clause. Now you are only interested in some of the groups, not all the groups. If you want to filter out some groups from the query,... 2016-10-25, 1261🔥, 0💬

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