Mutating Table Error In Sql Server
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Mutating Table Error In Oracle With Example
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Oracle Mutating Trigger Pragma Autonomous Transaction
others in the 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
Mutating Trigger With Example
by a design flaw 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 112238 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 e
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Ora-04091 Solution
Fix Oracle mutating trigger table errors Oracle Database Tips pragma autonomous_transaction in trigger by Burleson Consulting 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 http://dba.stackexchange.com/questions/5432/what-are-the-causes-and-solutions-for-mutating-table-errors changing. What this means to a trigger is 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 using a SELECT query), that changes (even using :NEW) will http://www.dba-oracle.com/t_avoiding_mutating_table_error.htm 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 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 trigg
- 8:40 pm UTC Category: SQL*Plus � Version: 8.1.7 Latest Followup You Asked hello, i've got a table MRC and a trigger on it (AFTER INSERT) thus, https://asktom.oracle.com/pls/apex/f?p=100:11:0%3A%3A%3A%3AP11_QUESTION_ID:9579487119866 after an insert in the table MRC, this trigger has to determine if a new line must be inserted into an other table PLAN : for that, it does compare the http://www.allinterview.com/showanswers/2737/what-is-mutating-table.html :new values with the MOST RECENT enregistrement of MRC but i got a mutating table error i understand the problem but how can i get over ?? thanks Arnaud and mutating trigger we said... My personal opinion -- when I hit a mutating table error, I've got a serious fatal flaw in my logic. Have you considered the multi-user implications in your logic? Two people inserting at the same time (about the same time). What happens then??? Neither will see eachothers work, neither will block -- both will think "ah hah, I mutating table error am first"... anyway, you can do too much work in triggers, this may well be that time -- there is nothing wrong with doing things in a more straightforward fashion (eg: using a stored procedure to implement your transaction) but if you persist, you can use the technique: http://asktom.oracle.com/~tkyte/Mutate/index.html to avoid the mutating table constraint -- but I would avoid the situation that gets me there in the first place. The logic is a whole lot more understandable that way (and maintainable and testable and everything) Reviews Write a Review Ora-4091 May 05, 2003 - 5:45 pm UTC Reviewer: A reader We create trigger in the test server (8i) its working without error, and when we created at life (8) we get the following error: ORA-04091: table XXXX is mutating, trigger/function may not see it. Followup May 05, 2003 - 8:31 pm UTC they relaxed some of the constraining rules between 8.0 and 8.1 -- things are in general upwards (develop in 8.0 and goto 8.1) compatible but not backwards. Why I can't get the 4091 error
PLSQL Suggest New Category What is mutating table? Question Posted / suji 11 Answers 43085 Views Saama Tech, I also Faced E-Mail Answers Answers were Sorted based on User's Feedback Answer / pavan_1981 A mutating table is a table that is currently being modified by an update, delete, or insert statement. For example, if your trigger contains a select statement or an update statement referencing the table it is triggering off of you will receive the error. Another way this error can occur is if the trigger has statements to change the primary, foreign or unique key columns of the table the trigger is triggering off of. Is This Answer Correct ? 119 Yes 5 No Answer / gopal Mutatation of table is a state of table when in before /after update trigger table tries to update the same table.As the call of update also calls same trigger then the trigger will be called infinite times. then the table will be mutating Is This Answer Correct ? 42 Yes 7 No Answer / kiran Mutating" means "changing". A mutating table is a table that is currently being modified by an update, delete, or insert statement. When a trigger tries to reference a table that is in state of flux (being changed), it is considered "mutating", and raises an error since Oracle should never return inconsistent data. Another way this error can occur is if the trigger has statements to change the primary, foreign or unique key columns of the table off which it fires. If you must have triggers on tables that have referential constraints, the workaround is to enforce the referential integrity through triggers as well. Is This Answer Correct ? 35 Yes 5 No Answer / swapnil siriah 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. The restrictions on such a table apply only to the session that issued the statement in progress. For all row triggers, that were fired as the result of a DELETE CASCADE, there are two important restrictions regarding mutating tables. These restrictions prevent a trigger from seeing an inconsistent set of data. The SQL statements of a trigger cannot read from (query) or modify a mutating table of the triggering statement. For eg:We have two tables "A" and "B". "A" is the master table