Database transaction

A database transaction is a logical unit of work that consists of one or more database operations, such as inserts, updates, or deletes, which are treated as a single, indivisible operation. The concept of transactions ensures data integrity, consistency, and reliability within a database system.

Key points about database transactions:

  1. Atomicity: Transactions are atomic, meaning that either all the operations within the transaction are successfully completed and committed to the database, or none of them are. If any part of the transaction fails, the entire transaction is rolled back, and the database returns to its state before the transaction started.

  2. Consistency: Transactions ensure that the database remains in a consistent state before and after their execution. This means that transactions preserve the integrity of the data and any constraints defined on the database schema.

  3. Isolation: Transactions are isolated from each other, meaning that the intermediate states of one transaction are not visible to other transactions until the transaction is completed (committed). This prevents interference between concurrent transactions and ensures data integrity.

  4. Durability: Once a transaction is committed, the changes made by the transaction are permanent and survive system failures. The database system ensures that committed transactions are reliably stored and can be recovered even in the event of a crash or power outage.

The system provides mechanisms for managing transactions, such as transaction logs, concurrency control, and rollback mechanisms, to ensure that transactions are executed reliably and efficiently.

Transactions are essential for maintaining data integrity and consistency in multi-user database environments, where multiple users may concurrently access and modify the same data. They provide a reliable mechanism for coordinating and managing concurrent access to the database, ensuring that data remains accurate and reliable even in complex scenarios.

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