How to handle concurrency access and transaction control in DB2?

Managing concurrent access and transaction control in DB2 typically involves the following aspects:

1. Locking mechanism: DB2 offers various locking levels, including shared locks and exclusive locks. By utilizing the locking mechanism, it ensures that data will not be simultaneously accessed or modified by other transactions while being accessed or modified.
2. Transaction Control: DB2 supports transaction control functionality, which allows grouping a set of database operations and ensuring that they either all succeed or all fail and are rolled back. This assists in maintaining data consistency and integrity.
3. Transaction Isolation Levels: DB2 supports different transaction isolation levels, including read uncommitted, read committed, repeatable read, and serializable. By setting the appropriate transaction isolation level, one can control potential issues that may arise during concurrent access, such as dirty reads, non-repeatable reads, and phantom reads.
4. Optimistic concurrency control: DB2 also supports optimistic concurrency control mechanism by using version control technology to avoid locking data, thereby improving the performance of concurrent access.

In general, DB2 offers a range of features and mechanisms for handling concurrent access and transaction control. Developers can choose the appropriate method based on specific needs and scenarios to ensure data integrity and consistency.