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What is mutating trigger in Oracle with an example?
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 mutating in the trigger Please select all the correct answers?
Mutating trigger is trigger that is currently being modified by DML opertion.
- sabrishandyou. Answered On : Jan 26th, 2010.
- There are cases when we have mutating table error inspite of using an “AFTER TRIGGER at ROW LEVEL”. This happens when you are using an after delete trigger.
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 the 12 types of triggers in Oracle?
Trigger Type Combinations
- BEFORE statement trigger. Before executing the triggering statement, the trigger action is run.
- BEFORE row trigger.
- AFTER statement trigger.
- AFTER row trigger.
What are the types of triggers in Oracle?
There are 3 different types of event triggers, they are:
- DDL EVENT TRIGGER. It fires with the execution of every DDL statement(CREATE, ALTER, DROP, TRUNCATE).
- DML EVENT TRIGGER. It fires with the execution of every DML statement(INSERT, UPDATE, DELETE).
- DATABASE EVENT TRIGGER.
How do you prevent mutating trigger errors?
Use an “after” or “instead of” trigger – If you must use a trigger, it’s best to avoid the mutating table error by using an “after” trigger, to avoid the currency issues associated with a mutating table.
How do you avoid mutating errors?
Don’t use triggers – The best way to avoid the mutating table error is not to use triggers. While the object-oriented Oracle provides “methods” that are associated with tables, most savvy PL/SQL developers avoid triggers unless absolutely necessary.
How do you handle a mutating trigger?
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 do you solve a mutating trigger?
Is mutating a trigger function?
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.
What is trigger write the different types of trigger with example?
Triggers are database object. Basically, these are a special type of stored procedure that is automatically fired/executed when a DDL or DML command statement related to the trigger is executed….Different Types of Triggers In SQL Server
- DDL Triggers.
- DML Triggers.
- CLR Triggers.
- Logon Triggers.
What is the mutating trigger error 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.
What is a mutation table in a trigger?
A mutation table is defined as a table that is changing. But in dealing with triggers, it is a table that has the possibility of changing.
What is mutating table error in Oracle 9i?
Mutating Tables. 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.
How do I avoid mutating table errors?
Use an “after” or “instead of” trigger – If you must use a trigger, it’s best to avoid the mutating table error by using an “after” trigger, to avoid the currency issues associated with a mutating table. For example, using a trigger “:after update on xxx”, the original update has completed and the table will not be mutating.