|
Oracle DCL and TCL - Posted on August 11, 2008 at 15:00 PM by
Amit Satpute
Explain DCL command.
Answer
DCL: Data Control Language
DCL are used to configure and control database objects.
Following are the DCL commands:
GRANT
REVOKE
What is TCL command?
Answer
TCL - Transaction Control: statements used to manage the changes made
by DML statements. It allows statements to be grouped together into logical
transactions.
-
COMMIT - save work done
-
SAVEPOINT - identify a point in a transaction to which you can later roll back
-
ROLLBACK - restore database to original since the last COMMIT
-
SET TRANSACTION - Change transaction options like isolation level and what
rollback segment to use
List the differences between GRANT and REVOKE command.
Answer
By using the GRANT command you can grant an system level previledge or role to
another user. The WITH ADMIN OPTION clause permits permits the guarantee to
bestow the privilege or role on other users.
The grantor can revoke the role from the user as well.
Privileges granted can be taken away. An individual with DBA role can revoke
CONNECT, RESOURCE and DBA or any other privilege from anyone including DBA.
Explain ROLLBACK and COMMIT command.
Answer
The transactions like update, insert or delete can be undone with the help of
rollback command. This is helpful when an introduced during your work.
COMMIT can be used to reflect the changes in the database. Until you commit, you
can only see how your work affects the tables. Anyone who is accessing the
database would be able to see the changes only after you have committed it.
This is with the help of CMMIT command.
What are difference between post database commit and post-form
commit?
Answer
Post-Database-Commit
It fires once during the Post and Commit Transactions process, after the
database commit occurs.
It fires after Oracle Forms issue the Commit to finalize the transaction.
The Post-Forms-Commit
It fires once during the Post and Commit Transactions process.
If there are records in the form that have been marked as inserts, updates, or
deletes, this trigger fires after these changes have been written to the
database but before Oracle Forms issues the database Commit to finalize the
transaction.
If the operator or the application initiates a Commit when there are no records
in the form have been marked as inserts, updates, or deletes,then Oracle Forms
fires these, without posting changes to the database.
|