Avoid Mutating Error In Oracle
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Fix Oracle mutating mutating trigger in oracle 10g with example trigger table errors Oracle tips by Burleson A mutation table is defined as a table thatOracle Compound Trigger
is changing. But in dealing with triggers, it is a table that has the possibility of changing. What this means to a trigger is mutating trigger in oracle 11g that if the trigger reads a table, it can not change the table that it read from. This does not impact the exclusive use of :OLD and :NEW. It says that if the trigger reads the table (such as oracle mutating trigger pragma autonomous transaction using a SELECT query), that changes (even using :NEW) will fail. This can also happen when a trigger on a parent table causes an insert on a child table referencing a foreign key. 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
Mutating Trigger With Example
to rewrite the trigger as a statement-level trigger. Mutating table errors only impact row level triggers. But to use a statement level trigger, some data may need to be preserved from each row, to be used by the statement level trigger. This data can be stored in a PL/SQL collection or in a temporary table. A simple row level trigger that causes a mutating table error can result in a very complicated statement level trigger to achieve the needed result. Here are some important items to remember about triggers. On insert triggers have no :OLD values. On delete triggers have no :NEW values. Triggers do not commit transactions. If a transaction is rolled back, the data changed by the trigger is also rolled back. Commits, rollbacks and save points are not allowed in the trigger body. A commit/rollback affects the entire transaction, it is all or none. Unhandled exceptions in the trigger will cause a rollback of the entire transaction, not just the trigger. If more than one trigger is defined on an event, the order in which they fire is not defined. If the triggers must fire in order, you must create one trigger that executes all the actions in the required order. A trigger can cause other events to execute triggers. A trigger can not change a table that it has read from. This is the mutating table error issue. The fact that
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Oracle Instead Of Trigger
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Editions: US United States Australia United Kingdom Japan Newsletters Forums Resource Library Tech Pro Free Trial Membership Membership My Profile People Subscriptions My stuff Preferences Send a message Log Out http://www.techrepublic.com/article/learn-to-avoid-the-mutating-table-problem-in-oracle/ TechRepublic Search GO Topics: CXO Cloud Big Data Security Innovation Software Data Centers Networking Startups Tech & Work All Topics Sections: Photos Videos All Writers Newsletters Forums Resource Library Tech Pro Free Trial Editions: US United States Australia United Kingdom Japan Membership Membership My Profile People Subscriptions My stuff Preferences Send a message Log Out Data Management Learn to avoid the mutating table problem mutating trigger in Oracle Mutating tables in Oracle can drive any IT database manager insane when it comes to tracking down the culprit. With a clear idea of the table design required, however, this problem can be avoided. By Scott Robinson | April 14, 2003, 12:00 AM PST RSS Comments Facebook Linkedin Twitter More Email Print Reddit Delicious Digg Pinterest Stumbleupon Google Plus Tables are everything to mutating trigger in IT database managers in ERP database environments. The organization of database tables, their relationships, and the manner in which they are managed are a fair indicator of the overall quality of performance you can expect from the system.So when something can happen to mess up your tables, you want to watch out for it. In Oracle, there’s a nasty snare out there waiting for you. It's Oracle error ORA-04091, the mutating table error, and the best way to deal with it is to avoid it altogether. This article will explain why.When tables mutateThere are several causes of mutating tables, but in general a table mutation error will result if you create a trigger on a table that attempts to examine the current table. Also, the error is given when an attempt is made to examine a parent table in a cascading update/delete.Why are these considered errors? It’s obvious when you think about it: The trigger is trying to change or examine something that’s already being changed. This confuses Oracle, and understandably so. In a row-level trigger firing, when the trigger is about to fire for the second row in a multirow