Oracle Locks   «Prev  Next»

Oracle Lock Modes - Exericse

Overview of Oracle lock modes

Objective: Describe the Oracle lock modes.

Exercise scoring

For this exercise, you will need to respond to the scenario presented below using what you now know about Oracle locks. Once you have completed your answer, you will submit your answer.


Your programming community has been having a problem when attempting to acquire a whole table with an exclusive lock (using the LOCK TABLE command). Their task is updating 3,000 rows in a table, and the task has been waiting too long for all shared locks to clear.
The programmers are upset because they cannot understand why the task must wait for shared locks. You have been asked to describe to your programmer community why Oracle will not allow a task to acquire an exclusive lock until all other tasks are done reading a row (with shared locks), and outline another method for achieving the goal.


Prepare a short paragraph explaining why it is necessary for Oracle to wait until all shared locks have cleared for a row before allowing an exclusive lock to be set. It should also explain another alternative to a full table lock.


Remember the discussion about Oracle's locking scheme from the beginning of this module.

Submitting your Exercise

Enter your answer into the text box below. Click the Submit button to submit your answer