Question: Can We Use TCL Commands In Trigger?

What are the DCL commands?

DCL(Data Control Language) : DCL includes commands such as GRANT and REVOKE which mainly deals with the rights, permissions and other controls of the database system.

Examples of DCL commands: GRANT-gives user’s access privileges to database.

REVOKE-withdraw user’s access privileges given by using the GRANT command..

What is mutating in the trigger?

A mutating table error (ORA-04091) occurs when a row-level trigger tries to examine or change a table that is already undergoing change (via an INSERT, UPDATE, or DELETE statement). In particular, this error occurs when a row-level trigger attempts to read or write the table from which the trigger was fired.

What is an autonomous transaction?

Autonomous Transactions. Autonomous transactions allow you to create a new transaction within a transaction that may commit. or roll back changes, independently of its parent transaction.

Does Drop require commit?

ALTER FUNCTION , CREATE FUNCTION and DROP FUNCTION also cause an implicit commit when used with stored functions, but not with user-defined functions. ( ALTER FUNCTION can only be used with stored functions.) CREATE TABLE and DROP TABLE statements do not commit a transaction if the TEMPORARY keyword is used.

Is insert auto commit?

The feature AUTOCOMMIT automatically performs a COMMIT after every write operation (INSERT, UPDATE, or DELETE). This feature is not part of the SQL standard, but is implemented and activated by default in some implementations.

Is delete DDL or DML?

DML is Data Manipulation Language which is used to manipulate data itself. For example: insert, update, delete are instructions in SQL. It stands for Data Definition Language. … Basic command present in DDL are CREATE, DROP, RENAME, ALTER etc.

Is commit required after grant in Oracle?

If you give grant to a table or create synonym for a table, thats it. It will be there unless you drop it or drop schema. If you do any table updation/deletion/insertion then you need to commit the session. That means for all DDL you no need commit.

Why commit is important after DML?

COMMIT command is used to permanently save any transaction into the database. When we use any DML command like INSERT , UPDATE or DELETE , the changes made by these commands are not permanent, until the current session is closed, the changes made by these commands can be rolled back.

Can we use commit in trigger?

Trigger should not commit and cannot commit. Committing in a trigger usually raises an exception unless it happens into autonomous transaction. When you open connection, Oracle creates session for it.

What are different transaction control commands with examples?

The following commands are used to control transactions.COMMIT − to save the changes.ROLLBACK − to roll back the changes.SAVEPOINT − creates points within the groups of transactions in which to ROLLBACK.SET TRANSACTION − Places a name on a transaction.

Is it possible to use transaction control statements in database triggers?

It is not possible. As triggers are defined for each table, if you use COMMIT of ROLLBACK in a trigger, it affects logical transaction processing.

Is commit necessary after insert?

It doesn’t matter: only full transactions require COMMIT. It literally does not make sense to issue a COMMIT unless or until we have completed a whole business unit of work. This is a key concept. COMMITs don’t just release locks.

Can we use Pragma Autonomous_transaction in trigger?

The trigger has pragma autonomous_transaction, and trigger works as intended. …

What is Pragma Autonomous_transaction in trigger?

The AUTONOMOUS_TRANSACTION pragma changes the way a subprogram works within a transaction. A subprogram marked with this pragma can do SQL operations and commit or roll back those operations, without committing or rolling back the data in the main transaction.

Is commit needed after insert?

So yes, by default, if you’re just using INSERT , the records you insert will be committed, and there is no point trying to roll them back. (This is effectively the same as wrapping each statement between BEGIN and COMMIT .)

What are transaction control commands?

Transaction Control Language commands are used to manage transactions in the database. These are used to manage the changes made by DML-statements. It also allows statements to be grouped together into logical transactions. COMMIT: Commit command is used to permanently save any transaction into the database.

Can we rollback after commit?

A transaction is a sequence of SQL statements that Oracle Database treats as a single unit. … After you commit the transaction, the changes are visible to other users’ statements that execute after the commit. You can roll back (undo) any changes made during the transaction with the ROLLBACK statement (see ROLLBACK.

What are the different types of DML and DDL commands?

DDL statements are used to create database, schema, constraints, users, tables etc. DML statement is used to insert, update or delete the records. DDL has no further classification. DML is further classified into procedural DML and non-procedural DML.