Final answer:
The statement is false. Multiple users can hold a shared lock for reading, but an exclusive lock would be blocked until all shared locks are released.
Step-by-step explanation:
The statement that if a user has a shared lock on a table, this will prevent any other user from obtaining a shared or exclusive lock on the same table is false. In database systems, a shared lock allows multiple users to read from the same table concurrently but prevents any from writing to it. Conversely, an exclusive lock prevents other users from both reading and writing to the table. Therefore, while an exclusive lock would prevent other users from obtaining a shared or exclusive lock, a shared lock only prevents a user from obtaining an exclusive lock. This is because a shared lock allows multiple users to read the table simultaneously, but it does not allow any user to modify the table. If another user tries to obtain a shared or exclusive lock, they will be blocked until the existing shared lock is released.