Avoid Mutating Error Oracle 10g
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Fix how to avoid mutating table error in oracle Oracle mutating trigger table errors Oracle tips by Burleson A mutation table is defined as a table that is how to solve mutating error in oracle changing. But in dealing with triggers, it is a table that has the possibility of changing. What this means to a trigger is that if the trigger reads a table, it canHow To Overcome Mutating Error In Oracle
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 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 mutating table error in oracle with example 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. 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 al
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Badges Unanswered Ask Question _ Database Administrators Stack Exchange is a question and answer site for database professionals who wish to improve their database skills and learn from others in the http://www.dba-oracle.com/t_avoiding_mutating_table_error.htm community. Join them; it only takes a minute: Sign up Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top What are the causes and solutions for mutating table errors? up vote 7 down vote favorite 1 I understand mutating table errors are caused by a design flaw http://dba.stackexchange.com/questions/5432/what-are-the-causes-and-solutions-for-mutating-table-errors or problematic query. An old query was recently put into production which throws a mutating table error. Our DBA solved the problem but we do not know how. What exactly causes mutating table errors and how would our DBA have fixed the problem? sql oracle trigger plsql share|improve this question edited Jun 25 '15 at 17:56 Mahi_0707 1033 asked Sep 6 '11 at 8:46 parmanand 107238 add a comment| 3 Answers 3 active oldest votes up vote 13 down vote accepted 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 This is an expected and normal behaviour, Oracle wants to protect you from yourself since Oracle guarantees: (i) that each statement is atomic (i.e will either fail or succeed completely) (ii) that each statement sees a consistent view of t
RESOURCES Database Tools SQL Scripts & Samples Links » Database Forum » Slideshows » Sitemap Free Newsletters: DatabaseDaily News http://www.databasejournal.com/features/oracle/article.php/3329121/The-Mutation-error-in-Oracle-Database-Triggers.htm Via RSS Feed Database Journal |DBA Support |SQLCourse |SQLCourse2 Featured Database Articles Oracle Posted Mar 23, 2004 The Mutation error in Oracle Database Triggers By Amar Kumar Padhi http://www.geekinterview.com/question_details/38972 The Mutating table error is a well-known problem encountered in development; most developers have come across this error. ORA-04091: table
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Was this answer useful?Yes Reply joseph0609 ProfileAnswers by joseph0609 Dec 5th, 2006 WE CAN RESOLVE IT BY NOT KEEPING A SELECT STMT INSIDE A TRIGGER IN MUTATING TRIGGERWE ARE SIMULTANEOUSLY READING THE VALUE AND WANTS TO UPDATE IT. SO WE BYPASS BY READING THE VALUE WITH A SEPERATE VARIABLE IN A PROCEDURE ,SO BYREADING THE OLD VALUE THROUGH THIS VARIABLE. AFTER STORING THE VALUE IN THAT VARIABLE WE ARE GOING FRO UPDATION . Was this answer useful?Yes Reply shravanam ProfileAnswers by shravanamQuestions by shravanam Oct 24th, 2007 WHE