A Transaction groups a set of tasks into a single execution unit. Each transaction begins with a specific task and ends when all the tasks in the group successfully finish.If all of these tasks execute successfully, then a transaction is committed and the changes made by T-SQL statements permanently saved to database. If any of the T-SQL statements within a transaction fail, then the complete transaction is cancelled/ rolled back.This blog illustrates how to use Transactions in Microsoft SQL Server.

How to begin a transaction?

You can begin a transaction with the BEGIN TRANSACTION statement.The BEGIN TRANSACTION statement notifies SQL Server to treat all of the following actions as a single transaction.

--Begin a new transaction

BEGIN TRANSACTION

You can also abbreviate the word TRANSACTION to TRAN as below:

--Begin a new transaction

BEGIN TRAN

Is it possible to name a transaction ?

Yes it's possible to name a transaction , a usefull feature in case we have opened multiple transactions within the same script

--Begin a new transaction with a name

BEGIN TRAN NamedTransaction

You can also use a variable to set the name of a transaction, as below :

DECLARE @TransactionName VARCHAR(50)
SET @TransactionName = 'NamedTransaction'
BEGIN TRAN @TransactionName 

How to end a transaction?

When you've started a transaction you must always explicitly end it either by using COMMIT or ROLLBACK

To commit a transaction you use the COMMIT statement, as shown below:

--Start a new transaction

BEGIN TRAN
--Changes inside the transaction
COMMIT

There are multiple wats to commit a transaction as shown below:

--Various ways to commit a transaction

COMMIT
COMMIT TRAN
COMMIT TRANSACTION
COMMIT TRAN NamedTransaction

If you want to revert the changes you can use the ROLLBACK statement.ROLLBACK statement rolls back an explicit or implicit transaction to the beginning of the transaction.

--Various ways to rollback a transaction

ROLLBACK
ROLLBACK TRAN
ROLLBACK TRANSACTION
ROLLBACK TRAN NamedTransaction

Can we nest transactions ?

Yes we can nest transactions as below:

BEGIN TRAN OuterTran
   --------------
    BEGIN TRAN InnerTran
      -----Inner transaction statemnets
    COMMIT TRAN InnerTran

COMMIT TRAN OuterTran

I hope after reading this article you will be able to work with transactions in SQL Server.