What are some examples of concurrency control in databases?

What are some examples of concurrency control in databases?

Concurrency control is essential in databases to ensure data integrity when multiple transactions occur simultaneously. Examples include locking mechanisms, timestamp ordering, and optimistic concurrency control.

Can you explain how locking mechanisms work?

Locking mechanisms prevent multiple transactions from accessing the same data simultaneously. There are two main types: exclusive locks, which allow only one transaction to access the data, and shared locks, which allow multiple transactions to read the data but not modify it.

What is optimistic concurrency control?

Optimistic concurrency control assumes that multiple transactions can complete without affecting each other. It checks for conflicts only at the time of committing the transaction, rolling back if a conflict is detected.

Are there any drawbacks to these methods?

Yes, locking can lead to deadlocks and reduced performance, while optimistic control may result in higher rollback rates if conflicts are frequent.