Quick Answer: Is Mutating Trigger Function May Not See It?

Can we use Pragma Autonomous_transaction in trigger?

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

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What is the difference between Pragma Exception_init and Raise_application_error?

pragma exception init turns an Oracle Error into a named exception. If a database operation raises an ORA-00054 “resource busy”, you would have to code: . Raise_application_error is used to RAISE an error – exception_init is used to deal with errors (i guess you could say they are opposites in a way).

How many triggers can be applied to a table?

There are 12 types of triggers can exist in a table in Oracle: 3 before statement, 3 after statement, 3 before each row and 3 after each row. On a single table you can define as many triggers as you need.

What is Pragma Autonomous_transaction?

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. … They pass information to the compiler.

What is difference between row level trigger and statement level trigger?

Row-level triggers execute once for each row in a transaction. … Statement-level triggers execute once for each transaction. For example, if a single transaction inserted 500 rows into the Customer table, then a statement-level trigger on that table would only be executed once.

What is compound trigger?

Description The compound trigger, added in 11.1, allows you to define variables which persist through the execution of the steps defined in the compound trigger. One very useful application of this feature is to simplify the code needed to avoid mutating table trigger errors. Area PL/SQL General / PL/SQL Triggers.

What is the mutating table and constraining table?

What is the mutating table and constraining table? Answer: A table which is currently being modified by a DML statement like defining triggers in a table is known as a Mutating table. A table that might need to be read from for a referential integrity constraint is known as constraining table.

What is a mutating table?

A mutating table is a table that is currently being modified by an UPDATE, DELETE, or INSERT statement, or it is a table that might need to be updated by the effects of a declarative DELETE CASCADE referential integrity constraint.

What is instead of trigger in Oracle?

What is an instead of trigger in Oracle. An INSTEAD OF trigger is a trigger that allows you to update data in tables via their view which cannot be modified directly through DML statements. When you issue a DML statement such as INSERT , UPDATE , or DELETE to a non-updatable view, Oracle will issue an error.

What are the after triggers?

After Trigger, Instead of Trigger ExampleAfter Trigger (using FOR/AFTER CLAUSE) This trigger fires after SQL Server completes the execution of the action successfully that fired it. … Instead of Trigger (using INSTEAD OF CLAUSE) This trigger fires before SQL Server starts the execution of the action that fired it.

Is mutating trigger function may not see it after insert?

Means if you run UPDATE OR INSERT OR DELETE statements on this table, the trigger will fire. But you are trying to update the same table again inside your trigger, which is compl. wrong. This this is why you are getting the error.

How do you avoid mutating errors?

In this trigger:First, declare an array of customer record that includes customer id and credit limit.Second, collect affected rows into the array in the row-level trigger.Third, update each affected row in the statement-level trigger.

What are triggers in Oracle?

Oracle allows you to define procedures that are implicitly executed when an INSERT, UPDATE, or DELETE statement is issued against the associated table. These procedures are called database triggers. … A trigger can include SQL and PL/SQL statements to execute as a unit and can invoke stored procedures.

What is autonomous transaction Oracle?

In Oracle’s database products, an autonomous transaction is an independent transaction that is initiated by another transaction. … Autonomous transactions allow a single transaction to be subdivided into multiple commit/rollback transactions, each of which will be tracked for auditing purposes.

How do you check if a trigger is fired?

To test if a trigger fires you can add a PRINT statement to the trigger (e.g. “PRINT ‘trigger fired!’ “), then do something that should trigger the trigger. If you get the printed text in your messages-tab in management studio you know it fired.

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.

How do you check a trigger is fired or not in Oracle?

You can check the status from any of the xxx_TRIGGERS views. For a currently running user_triggers is the table where all triggers created, specific to the schema, are located. So, SELECT STATUS FROM USER_TRIGGERS WHERE TRIGGER_NAME = ‘the_trigger_name’; will fetch the status of either ENABLED or DISABLED.

Can we commit inside a trigger?

Trigger should not commit and cannot commit. Committing in a trigger usually raises an exception unless it happens into autonomous transaction.

Can trigger change the table from which it has been called?

A trigger cannot change the table from which it has been called. If there is a trigger called as a result of insert on a table, then the trigger cannot insert/update the same table.

How can you retrieve the error code and error message of an Oracle server exception?

Retrieving the Error Code and Error Message: SQLCODE and SQLERRM. In an exception handler, you can use the built-in functions SQLCODE and SQLERRM to find out which error occurred and to get the associated error message. For internal exceptions, SQLCODE returns the number of the Oracle error.

Why do we use triggers?

Triggers help the database designer ensure certain actions, such as maintaining an audit file, are completed regardless of which program or user makes changes to the data. The programs are called triggers since an event, such as adding a record to a table, fires their execution.