What are magic tables in Triggers SQL Server?

What are magic tables in Triggers SQL Server?

Magic Tables are invisible tables or virtual tables. You can see them only with the help Triggers in SQL Server. Magic Tables are those tables which allow you to hold inserted, deleted and updated values during insert, delete and update DML operations on a table in SQL Server.

What are the virtual tables in Triggers?

Inserted and Deleted are the two tables that are virtual and is used by a trigger in order to store the data that is inserted and deleted using a trigger.

What are magic tables how many are there and when will they be created?

There are two types of Magic tables created at the time of insertion/updation/deletion in SQL server: INSERTED. DELETED.

What are pseudo tables in SQL Server?

Pseudocolumn: A pseudo-column behaves like a table column but is not actually stored in the table. You can select from pseudo-columns, but you cannot insert, update, or delete their values. A pseudo-column is also similar to a function without arguments.

What is magical table in SQL?

June 23, 2020 by Jignesh Raiyani. There are Magic Tables (virtual tables) in SQL Server that hold the temporal information of recently inserted and recently deleted data in the virtual table. INSERTED and DELETED are two types of magic tables in SQL Server.

How many types of Triggers in SQL Server?

In SQL Server we can create four types of triggers Data Definition Language (DDL) triggers, Data Manipulation Language (DML) triggers, CLR triggers, and Logon triggers.

Where are magic tables stored in SQL Server?

A magic table is stored in the temp DB. Therefore, whenever you use the magic tables in SQL Server with the query statement, tempdb will come in the picture.

How do I add a trigger to a table in SQL Server?

Create trigger SQL Script

  1. Create TRIGGER [Tr_CreateNewTableByHost]
  2. ON DATABASE.
  3. FOR CREATE_TABLE.
  4. AS.
  5. BEGIN.
  6. declare @hostname varchar(30)
  7. select @hostname = hostname FROM sys.sysprocesses WHERE spid = @@SPID.
  8. Print ‘New Table Created’ + ‘ At ‘ + cast(Getdate() as nvarchar(20))+’ Using Hostname ‘[email protected]

What is a magic table in SQL Server?

A magic table can be utilized in INSERT, UPDATE, and DELETE activity with the table in a trigger, which is the common understanding of people. SQL Server uses magic tables outside the TRIGGER also for a lot of other purposes too.

What is the use of magic table in trigger?

Basically, magic tables are used by triggers for the following purposes. The Inserted table holds the recently inserted values, in other words new data values. Hence recently added records are inserted into the Inserted table.

What are the two types of triggers in SQL Server?

The following are the two types of triggers in SQL Server. After Triggers (For Triggers): Fired after Insert, Update and Delete operations on a table. Instead of Triggers: Fired instead of Insert, Update and Delete operations on a table. What are the special tables used by Triggers in SQL Server?

What is DML trigger in SQL Server?

A common use of Magic tables in SQL Server is the DML (Data Manipulation Language) trigger. SQL Server DML trigger allows using these two virtual tables INSERTED and DELETED. The ideal use of the trigger is auditing and managing a before and after version of the table row on INSERT, UPDATE, or DELETE operation within the transaction statement.

Related Posts