What is transaction in oracle

A transaction is an inseparable set of logical operations in the Oracle database, either all succeed or all fail. Its properties include atomicity, consistency, isolation, and durability. A transaction consists of data operation statements, transaction control statements and data structures. Its life cycle includes start, execution, commit or rollback. Transactions ensure data integrity, improve performance, handle errors, and simplify the user interface.

Transactions in Oracle

A transaction is a group of related operations in the Oracle database and is considered an unavailable Logical unit of segmentation. It either all succeeds or all fails.

Characteristics of transactions (ACID)

Transactions have the following properties, which are called ACID properties:

• Atomicity ( Atomicity): All operations in the transaction either all occur or all are rolled back.
• Consistency: The database state before and after transaction execution is consistent and complies with business rules.
• Isolation: Transactions executed at the same time are isolated from each other and are not affected by other transactions.
• Durability (Durability): Once a transaction is committed, the changes made to the database will take effect permanently and will not be lost even if the system fails.

Composition of transaction

A transaction consists of the following parts:

• Data operation statement (DML):INSERT, UPDATE, DELETE and other statements.
• Transaction control statements: BEGIN, COMMIT, ROLLBACK and other statements.
• Data structure: Table, view, index, etc.

Transaction life cycle

The transaction life cycle includes the following steps:

• Start: Start a transaction explicitly using the BEGIN statement or through an implicit session.
• Execution: Execute data operation statements.
• Commit: Use the COMMIT statement to permanently apply changes to the database.
• Rollback: Use the ROLLBACK statement to undo changes to the database.

Purpose of transactions

Transactions are used in Oracle database to:

• Ensure data integrity:Ensure the consistency and accuracy of database status through ACID characteristics.
• Improve performance: Reduce database access and locking by processing multiple operations as a unit.
• Handling errors: Allows transactions to be rolled back when errors occur to prevent data corruption.
• Simplification of user interface: Provide users with "atomic" operations, simplifying interactions and reducing errors.

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