What's the difference between an exclusive lock and a shared lock?

Question

According to wikipedia,

Shared locks are sometimes called \"read locks\" and exclusive locks are sometimes called \"write locks\".

Answer 1

Principle same on the database side as well. As per the Oracle documentation

Exclusive lock mode prevents the associated resource from being shared. This lock mode is obtained to modify data. The first transaction to lock a resource exclusively is the only transaction that can alter the resource until the exclusive lock is released.

Share lock mode allows the associated resource to be shared, depending on the operations involved. Multiple users reading data can share the data, holding share locks to prevent concurrent access by a writer (who needs an exclusive lock). Several transactions can
acquire share locks on the same resource.