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.
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 is mutating table error in Oracle?
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 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 is mutating table?
What is mutating table error?
What is ref cursor in Oracle?
A REF CURSOR is a PL/SQL data type whose value is the memory address of a query work area on the database. In essence, a REF CURSOR is a pointer or a handle to a result set on the database. REF CURSOR s are represented through the OracleRefCursor ODP.NET class.
Is mutating a trigger?
What is mutating trigger in Oracle with an example?
What is mutating table Oracle?
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.
What does a mutating table do in PLSQL?
A mutating table occurs when a statement causes a trigger to fire and that trigger references the table that caused the trigger. The best way to avoid such problems is to not use triggers, but I suspect the DBA didn’t take the time to do that. He could have done one of the following: Changed the trigger to an after trigger.
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 causes an ora-04091 error in Oracle?
The most likely cause of a mutating table error is the misuse of triggers. Here is a typical example: you insert a row in table A. a trigger on table A (for each row) executes a query on table A, for example to compute a summary column. Oracle throws an ORA-04091: table A is mutating, trigger/function may not see it.