States of a transaction Active state •
This is the first state in the lifecycle of the transaction. When a transaction starts execution, it enters the active state. It stays here as long as the sequential steps within the transaction are executed. While executing, the transaction will make certain changes to the state of a database. These changes are stored in buffered memory temporarily.
Partially committed state •
Once the transaction completed execution in the active state, it enters the partially committed state. This state is so named because the transaction is not yet complete and hence partial executed. The transaction is not completed until unless the changes are reflected in the database. A transaction with changes written in buffer memory is called as a partially committed transaction as the changes are not reflected in the database.
Committed state •
Once the transaction executes properly and is ready to be committed to database, it enters the committed state. This state deals with writing and reflecting the changes of a transaction within the database. Once a transaction reaches this state, it cannot be rolled back. If one has to revoke the changes, a new transaction with given reverted changes must be executed.
Failed state •
When a given transaction is executing in active state or is present in the partially committed state, if any abrupt event happens then the transaction moves to the failed state and the changes are not reflected in the database.
Aborted state •
Once the transaction enters failed state, the changes made by the transaction must be undone. This is done by rolling back the transaction and then entering the aborted state.
