How do you overcome a mutating trigger in Oracle?

The Oracle mutating trigger error occurs when a trigger references the table that owns the trigger, resulting in the “ORA-04091: table name is mutating, trigger/function may not see it.” message. Don’t use triggers – The best way to avoid the mutating table error is not to use triggers.

How can we prevent mutating error using compound trigger?

CREATE OR REPLACE TRIGGER equitable_salaries_astrg AFTER INSERT OR UPDATE ON employees BEGIN equitable_salaries_pkg. make_equitable; END; And now the update statement will work without raising any ORA-04091 errors! Yep.

What is a mutating table in Oracle?

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 are mutating trigger?

Mutating trigger is trigger that is currently being modified by DML opertion. For eg.,You created a trigger trigger1 on table1, it should fire after update for each row. And you wrote some update statement on the same table (table1) inside the trigger .

What happens if a trigger fails in Oracle?

Statements are atomic in Oracle (as they should be in all databases). So, after your insert, if the trigger failed – the database will look like your insert never ever happened.

How do you resolve a mutating table error?

Fixing the mutating table error

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.

How many triggers can be applied to a table?

Triggers are implicitly fired by Oracle when a triggering event occurs, no matter which user is connected or which application is being used. 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.

Can a table have more than one trigger?

SQL Server allows multiple triggers on the table for the same event and there is no defined order of execution of these triggers. There can be only one first or last trigger for each statement on a table. Below is the sample syntax for setting the order of trigger to first for the INSERT statement.

Can we commit after rollback?

No, you can’t undo, rollback or reverse a commit.

What to do when trigger table is mutating in Oracle?

Each new release of the Oracle database reduces the impact of the mutating table error on triggers and they are much less of a problem with Oracle9i and above. If a trigger does result in a mutating table error, the only real option is to rewrite the trigger as a statement-level trigger. Mutating table errors only impact row level triggers.

Is there a way to fix the mutating table error?

To fix the mutating table error, you can use a compound trigger if you are using Oracle 11g and later. Note that if you’re using Oracle 10g or earlier, you need to use a package to fix the mutating table error, which we will not cover in this tutorial.

What is average for mutating table ask Tom?

1. Since its an after update trigger, the trigger would use the updated values for the rows updated so far. 2. The first time the trigger is executed, average is (4000 + 2000) / 2 = 3000. And (4000/2) < 3000 so Row 1 passes. 3. For row 2, average is (4000 + 5000) / 2 = 4500.

When does the mutating table issue crop up?

Anyway, the mutating table issue won’t crop up during a single row insert. you’ll get the mutating table issue — for even though you are just inserting a single row, the database no longer knows that. If I use ‘Insert into table SELECT …’,The 4091 error will happen,if only insert one record,It does not happen,but I want to know why?