What is the difference between shared and exclusive locks?

Can you explain the difference between shared and exclusive locks?

Sure! Shared locks allow multiple transactions to read a resource simultaneously, while exclusive locks prevent others from accessing the resource.

Why would I use a shared lock instead of an exclusive lock?

You would use a shared lock when you want to allow concurrent reads without blocking other transactions, which is useful for performance.

What happens if a transaction holds an exclusive lock?

If a transaction holds an exclusive lock, no other transaction can acquire either shared or exclusive locks on that resource until it's released.

Can you give an example of when to use each type of lock?

Certainly! Use a shared lock when multiple users need to read data, and an exclusive lock when a user needs to update or delete data.