Transaction: A transaction is a collection of operations that performs a single logical function in a database application. Such as, when we want to add BDT 500 to account A and subtract BDT 500 from account B, that will be a transaction.
Transaction Management: Transaction is a unit of both atomicity and consistency. Thus it is required that transaction should not violet the consistency of a database. This is the responsibility of the transaction management to ensure the atomicity and durability properties. Actually before a transaction starts functioning, the consistent state of the database gets recorded. If any kind of failure occurs during the transaction the database will be restored to the last recorded consistent state of the database. This is the job of the transaction management component.