Mutating Table Error Oracle
Contents |
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 mutating trigger in oracle 11g of this site About Us Learn more about Stack Overflow the company Business mutating trigger in oracle 10g with example Learn more about hiring developers or posting ads with us Database Administrators Questions Tags Users Badges Unanswered Ask Question
Mutating Trigger With Example
_ 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
Oracle Mutating Trigger Pragma Autonomous Transaction
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 or problematic query. An old query was oracle statement level trigger 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 each statement sees a consistent view of the data Most likely when you write this kind of trigger you would expect the quer
Social Links Printer Friendly About Search 8i | 9i | 10g | 11g | 12c | 13c | Misc | PL/SQL | SQL | RAC | WebLogic | Linux Home » Articles » 9i » Here Mutating Table
Pragma Autonomous_transaction In Trigger
Exceptions Mutating table exceptions occur when we try to reference the triggering table in a ora-04091 solution query from within row-level trigger code. In this article I'll present examples of how a mutating table exception might occur and simple oracle instead of trigger methods to get round it. Test Schema Mutating Table Demonstration Solution 1 (Collection in Package Variable) Solution 2 (Global Temporary Table) Test Schema The following schema objects are necessary to run the code in this article. http://dba.stackexchange.com/questions/5432/what-are-the-causes-and-solutions-for-mutating-table-errors CREATE TABLE tab1 ( id NUMBER(10) NOT NULL, description VARCHAR2(50) NOT NULL ); ALTER TABLE tab1 ADD ( CONSTRAINT tab1_pk PRIMARY KEY (id) ); CREATE SEQUENCE tab1_seq; CREATE TABLE tab1_audit ( id NUMBER(10) NOT NULL, action VARCHAR2(10) NOT NULL, tab1_id NUMBER(10), record_count NUMBER(10), created_time TIMESTAMP ); ALTER TABLE tab1_audit ADD ( CONSTRAINT tab1_audit_pk PRIMARY KEY (id) ); ALTER TABLE tab1_audit ADD ( CONSTRAINT tab1_audit_tab1_fk FOREIGN KEY (tab1_id) REFERENCES tab1(id) ); CREATE SEQUENCE tab1_audit_seq; Mutating https://oracle-base.com/articles/9i/mutating-table-exceptions Table Demonstration Let's assume we need to audit the actions on the parent table and for some reason, this involves querying the triggering table. We can demonstrate this with the following package and trigger. We place all our trigger code into a package as follows. CREATE OR REPLACE PACKAGE trigger_api AS PROCEDURE tab1_row_change (p_id IN tab1.id%TYPE, p_action IN VARCHAR2); END trigger_api; / SHOW ERRORS CREATE OR REPLACE PACKAGE BODY trigger_api AS PROCEDURE tab1_row_change (p_id IN tab1.id%TYPE, p_action IN VARCHAR2) IS l_count NUMBER(10) := 0; BEGIN SELECT COUNT(*) INTO l_count FROM tab1; INSERT INTO tab1_audit (id, action, tab1_id, record_count, created_time) VALUES (tab1_audit_seq.NEXTVAL, p_action, p_id, l_count, SYSTIMESTAMP); END tab1_row_change; END trigger_api; / SHOW ERRORS Next we create the row-level trigger itself to catch any changes to the table. CREATE OR REPLACE TRIGGER tab1_ariu_trg AFTER INSERT OR UPDATE ON tab1 FOR EACH ROW BEGIN IF inserting THEN trigger_api.tab1_row_change(p_id => :new.id, p_action => 'INSERT'); ELSE trigger_api.tab1_row_change(p_id => :new.id, p_action => 'UPDATE'); END IF; END; / SHOW ERRORS If we try to insert into the TAB1 table we might expect the insert to complete and the audit record to be created but as you can see below this is not the case. SQL> INSERT INTO tab1 (id, description) VALUES (tab1_seq.NEXTVAL, 'ONE'); INSERT INTO tab1 (id, description) VALUES (tab1_seq.NEXTVAL, 'ONE') * ERROR at
Load Balancing Mobile Devl Networking News Open Source Oracle Outsourcing Performance Tuning Protocols Security Sharepoint SQL Server Technology Unix Virtual Server Visual Studio VMWare Windows Windows Vista Questions? Please send https://decipherinfosys.wordpress.com/2009/06/22/mutating-tabletrigger-error-and-how-to-resolve-it/ your wish list of things that you would like us to write http://www.akadia.com/services/ora_mutating_table_problems.html about or if you have suggestions to help improve this blog site. You can send all questions/suggestions to: Blog Support Archives Archives Select Month May 2016 (1) April 2016 (1) March 2016 (1) April 2013 (1) February 2013 (1) August 2012 (1) April 2012 (3) March 2012 (6) February mutating trigger 2012 (2) November 2011 (1) July 2011 (3) June 2011 (1) April 2011 (1) March 2011 (1) February 2011 (7) January 2011 (5) December 2010 (1) October 2010 (1) August 2010 (3) July 2010 (3) June 2010 (14) May 2010 (5) April 2010 (4) March 2010 (5) February 2010 (6) January 2010 (10) December 2009 (10) November 2009 (5) October 2009 mutating trigger in (7) August 2009 (1) July 2009 (18) June 2009 (30) May 2009 (24) April 2009 (35) March 2009 (49) February 2009 (41) January 2009 (30) December 2008 (26) November 2008 (32) October 2008 (25) September 2008 (20) August 2008 (32) July 2008 (31) June 2008 (22) May 2008 (27) April 2008 (27) March 2008 (32) February 2008 (33) January 2008 (29) December 2007 (23) November 2007 (30) October 2007 (33) September 2007 (29) August 2007 (33) July 2007 (32) June 2007 (41) May 2007 (32) April 2007 (37) March 2007 (56) February 2007 (97) January 2007 (37) Blog Stats 6,864,288 Views Email Subscriptions Subscribe to Systems Engineering and RDBMS via Email RSS Subscriptions Subscribe to Systems Engineering and RDBMS via RSS Feed Recent Posts SQL Server 2016 - RTM on June1st Blockchain SSMS and .Net Framework4.5.1 SQL Server Virtualization Custom Search You can use our customized Search Engine based on Google's Co-op to narrow down your searches and get focussed results. Calendar June 2009 M T W T F S S « May Jul » 1234567 891011121314 15161718192021 22232425262728 2930
4 ORA-04088: error during execution of trigger 'TRG_GET_ID_APP'. We studied the "Mutating Table" Problem and found the following explanations in the Oracle8i Application Developer's Guide. 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. Example 1 Select in a mutating table from a row trigger (Tested on Oracle 8.1.7) We want to explain this situation on an example. We have two tables "A" and "B". "A" is the master table and "B" the detail table. We specified a foreign key between "B" and "A" with the CASCADE DELETE option. Here are the CREATE statements drop table B; drop table A; create table A ( ida number not null, vala varchar2(10), primary key(ida)); create table B ( idb number, valb varchar2(10), foreign key (idb) references A (ida) on delete cascade) / create or replace trigger b_br after delete on B for each row declare n integer; begin select count(*) into n from A; dbms_output.put_line('there are ' || n || ' rows in A'); dbms_output.put_line('after statment on B'); dbms_output.new_line; end; / insert into A values(1,'Table A'); insert into A values(2,'Table A'); insert into B values(1,'Table B'); insert into B values(1,'Table B'); commit; set serveroutput on; delete from A where idA = 1; ERROR at line 1: ORA-04091: table SCOTT.A is mutating, trigger/function may not see ORA-06512: at "SCOTT.B_BR", line 4 ORA-04088: error during execution of trigger 'SCOTT.B_BR' Notice that the SQL statement ( "select count(*) into n from A" ) is run for the first row of the table, and then the AFTER row trigger B_BR is fired. In turn, a statement in the AFTER row trigger body attempts to query the original table A. However, because the table A is mutating due to the CASCADE DELETE foreign key, this query is not allowed by Oracle. If attempted, a runtime error occurs, the effects of the trigger body and triggering statement are rolled ba