Transaction Management
- Computer Science Department
Transaction Management is an essential part of any database system that aims to maintain consistency and reliability in the data. Transactions in a database environment refer to a single logical operation of a data. It can be a single task consisting of multiple related operations.
There are several key concepts related to Transaction Management in a database:
Atomicity: Atomicity ensures that all operations within a particular transaction are completed successfully; otherwise, the transaction is aborted at the failure point and all the operations are rolled back to their previous state.
Consistency: Consistency ensures that a transaction brings the database from one valid state to another, maintaining the database schema's integrity constraints.
Isolation: The isolation property ensures that each transaction is executed in a manner that is isolated from other transactions. That is, the execution of one transaction does not affect the execution of another transaction.
Durability: Durability ensures that once a transaction has been committed, it remains so, even in the event of power loss, crashes, or errors. It guarantees that committed transactions persist that do not disappear or change.
Here is how transaction management works:
Begin Transaction: A point where the transaction begins.
Commit: If a transaction has reached a point where it can be committed, it means that the transaction has been executed successfully, and changes to the database can be permanently saved.
Rollback: If any error or interruption happens during the transaction, then all the changes need to be undone, and the database should revert back to the state before the transaction began. This is called a Rollback.
Savepoint: Savepoints are the placeholders which can be used to divide a transaction into smaller parts. It allows rolling back part of a transaction.
In a multi-user or a distributed environment, concurrent transactions can lead to various types of conflicts. The role of transaction management is also to resolve these conflicts. This is achieved by techniques like locking, timestamp-based concurrency control, optimistic concurrency control, etc.
The management of transactions is crucial in a database system because it ensures data integrity, consistency, and helps maintain the overall health of the database.