Question

The SELECT...FOR UPDATE command will automatically obtain a(n) ____________________ lock on the row to be changed.

a) Exclusive lock
b) Shared lock
c) Read lock
d) Write lock

Answer 1

The SELECT...FOR UPDATE command obtains an exclusive lock on the selected rows, preventing other transactions from accessing them until the current transaction is completed.

Step-by-step explanation:

The SELECT...FOR UPDATE command in the context of SQL databases is used to lock the selected rows to prevent other transactions from reading or modifying them until the current transaction is committed or rolled back. This command will automatically obtain a(n) exclusive lock on the row to be changed. The exclusive lock ensures that no other transaction can obtain a lock of any kind (read or write) on the affected row, which helps maintain data integrity during the update operation.