How does CICS handle transaction isolation and concurrency control?

How does CICS handle transaction isolation and concurrency control?

CICS (Customer Information Control System) provides transaction isolation and concurrency control through various mechanisms:

1. Isolation Levels: CICS allows users to specify different isolation levels for transactions, such as READ UNCOMMITTED, READ COMMITTED, REPEATABLE READ, and SERIALIZABLE, to control the visibility of data changes made by concurrent transactions.
2. Locking Mechanisms: CICS uses locking mechanisms to prevent multiple transactions from simultaneously accessing or modifying the same data. It supports various types of locks, including shared locks and exclusive locks, to ensure data consistency.
3. Commit and Rollback: CICS supports transaction management operations like COMMIT and ROLLBACK to maintain data integrity. Transactions can either commit changes to the database or rollback changes in case of errors or failures.
4. Resource Management: CICS manages resources efficiently by coordinating access to shared resources, such as databases and files, to avoid conflicts and ensure data consistency among concurrent transactions.

Overall, CICS effectively handles transaction isolation and concurrency control to ensure data integrity and consistency in multi-user environments.