Page 200 - SQL

Chapter 56: Transactions

Remarks

A transaction is a logical unit of work containing one or more steps, each of which must complete
successfully in order for the transaction to commit to the database. If there are errors, then all of
the data modifications are erased and the database is rolled back to its initial state at the start of
the transaction.

Examples

Simple Transaction

BEGIN TRANSACTION
INSERT INTO DeletedEmployees(EmployeeID, DateDeleted, User)
(SELECT 123, GetDate(), CURRENT_USER);
DELETE FROM Employees WHERE EmployeeID = 123;
COMMIT TRANSACTION

Rollback Transaction

When something fails in your transaction code and you want to undo it, you can rollback your
transaction:

BEGIN TRY
BEGIN TRANSACTION
INSERT INTO Users(ID, Name, Age)
VALUES(1, 'Bob', 24)

DELETE FROM Users WHERE Name = 'Todd'
COMMIT TRANSACTION
END TRY
BEGIN CATCH
ROLLBACK TRANSACTION
END CATCH

Read Transactions online: https://riptutorial.com/sql/topic/2424/transactions

https://riptutorial.com/ 182