Why do we need a Rollback command while making a transaction or tell me a when is it appropriate to use "ROLLBACK"

Question

In the code below when I am inserting data in a table then what is the purpose of rollback I should not insert it if I want to rollback so what is the appropriate way to use rollback?

BEGIN TRANSACTION Insert into dimCustomr Values('xyz',345435353) ROLLBACK;

Answer 1

Using the rollback method, you can close the transaction, reverting all associated changes made to the database. Eg:

Above diagram illustrate the three query at a time.Tansaction of query1 & query2 were successful but query3 got error. And when query3 got error all transaction will revert.

Answer 2

A Rollback is executed if a transaction aborts. It makes the whole Transaction undone. A transaction could be aborted through several errors that might occour when running the transaction or if you does an unplaned power off of your system.