SQL Transaction

Question

ID	Name	Age	Department
1	Ashish	25	DotNet
2	Mohit	26	DotNet
3	Amit	24	DotNet

Hello Sir,
              we have a table name - Employee & ID is auto genrate. suppose i want to delete the record with this query.

Delete from Employee Where ID=2
but after delete the record i want to again rollback how is it posible . plz explain me with easy way (i want to rollback )
and what is the diff b/w rollback & Commit

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