Oracle Mutating Trigger Error
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Fix Oracle mutating triggerOracle Mutating Trigger Pragma Autonomous Transaction
table errors Oracle Database Tips by Burleson Consulting A mutation table is defined as a table that is changing. But statement level trigger in oracle 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 can not change the pragma autonomous_transaction in trigger 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 Tables Each new release of the
Mutating Table Error In Oracle 11g With Example
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 all or none. Unhandled exceptions in the trigger will cause a rollback of the entire transactio
- 8:40 pm UTC Category: SQL*Plus � Version: 8.1.7 Whilst you are here, check out some content from the AskTom team: A Handwritten Message or Why It ora-04091 solution Paid to Write a Book (and homage to Richard Bolz) Latest Followup oracle instead of trigger You Asked hello, i've got a table MRC and a trigger on it (AFTER INSERT) thus, after an insert
Oracle After Trigger
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 :new values http://www.dba-oracle.com/t_avoiding_mutating_table_error.htm 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 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 https://asktom.oracle.com/pls/apex/f?p=100:11:0%3A%3A%3A%3AP11_QUESTION_ID:9579487119866 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 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 rul
log in tour help Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring developers http://dba.stackexchange.com/questions/5432/what-are-the-causes-and-solutions-for-mutating-table-errors or posting ads with us Database Administrators Questions Tags Users 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 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 trigger mutating table errors? up vote 7 down vote favorite 1 I understand mutating table errors are caused 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 oracle mutating trigger '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 each statement sees a consistent view of the data Most likely when you write this kind of trigger you would expect the query (2) to see the row inserted on (1). This would be in contradiction with both points above since the update is not finished yet (there could be more rows to be inserted). Oracle could return the result consistent with a point in time just before the beginning of the statement but from most of the examples I have seen that try to implement this logic, people see a multi-row statement as a serie of successive steps and expect the statement [2] to see the changes made by the previous steps. Oracle can not return the expected result and therefore throws the error. For further reading: "mutating