ORA-04091: table xxx is mutating, trigger/function may not see it

Connected to Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 

Connected as tbcs

 

SQL> 

SQL> 

SQL> drop trigger tbcs.TRG_CJW_TEST;

 

drop trigger tbcs.TRG_CJW_TEST

 

ORA-04080: trigger 'TRG_CJW_TEST' does not exist

SQL> drop table tbcs.cjw_test;

 

drop table tbcs.cjw_test

 

ORA-00942: table or view does not exist

SQL> create table cjw_test

  2  (

  3  itemid1    varchar2(10),

  4  itemid2    varchar2(10),

  5  itemid3    varchar2(10)

  6  );

 

Table created

SQL> insert into cjw_test values('1','1','1');

 

1 row inserted

SQL> commit;

 

Commit complete



/*

对于after 类型的 for each row 级别的triggers，不论哪种insert语句触发了trigger，

都不允许在 trigger 中访问本trigger所依赖的table的

*/



SQL> create or replace trigger trg_cjw_test

  2    after insert on tbcs.cjw_test

  3    for each row

  4  declare

  5    i   number:=0;

  6  begin

  7    select count(1) into i from tbcs.cjw_test;

  8  end trg_cjw_test;

  9  /

 

Trigger created

 

SQL> insert into cjw_test values('1','1','1');

 

insert into cjw_test values('1','1','1')

 

ORA-04091: table TBCS.CJW_TEST is mutating, trigger/function may not see it

ORA-06512: at "TBCS.TRG_CJW_TEST", line 4

ORA-04088: error during execution of trigger 'TBCS.TRG_CJW_TEST'

 

SQL> 

SQL> 

/*

对于before 类型的 for each row 级别的triggers，如果使用 insert into ... values 语句触发此trigger ，

则在trigger 中访问本table没有问题；但如果使用 insert into select .. from 语句触发此trigger ，

则在trigger 中访问本table就报ora-04091错误；

*/



SQL> create or replace trigger trg_cjw_test

  2    before insert on tbcs.cjw_test

  3    for each row

  4  declare

  5    i   number:=0;

  6  begin

  7    select count(1) into i from tbcs.cjw_test;

  8  end trg_cjw_test;

  9  /

 

Trigger created

 

SQL> insert into cjw_test values('1','1','1');

 

1 row inserted

 

SQL> commit;

 

Commit complete

 

SQL> 

SQL> create or replace trigger trg_cjw_test

  2    before insert on tbcs.cjw_test

  3    for each row

  4  declare

  5    i   number:=0;

  6  begin

  7    insert into tbcs.cjw_test

  8    select '2','2','2' from dual;

  9  end trg_cjw_test;

 10  /

 

Trigger created

 

SQL> insert into cjw_test values('1','1','1');

 

insert into cjw_test values('1','1','1')

 

ORA-04091: table TBCS.CJW_TEST is mutating, trigger/function may not see it

ORA-06512: at "TBCS.TRG_CJW_TEST", line 4

ORA-04088: error during execution of trigger 'TBCS.TRG_CJW_TEST'

ORA-06512: at "TBCS.TRG_CJW_TEST", line 4

ORA-04088: error during execution of trigger 'TBCS.TRG_CJW_TEST'

 

SQL> 



 SQL> 

/*

上面实验中使用before，我们在仅插入一条数据的情况下，并没有报错，现在试一下插入多条数据的情况

*/

SQL> create or replace trigger trg_cjw_test

  2    before insert on tbcs.cjw_test

  3    for each row

  4  declare

  5    i   number:=0;

  6  begin

  7    select count(1) into i from tbcs.cjw_test;

  8  end trg_cjw_test;

  9  /

 

Trigger created

 

SQL> 

SQL> create table cjw_test_bak as select * from cjw_test;

 

Table created

SQL> insert into cjw_test_bak values('2','1','1');

 

1 row inserted

SQL> insert into cjw_test_bak values('3','1','1');

 

1 row inserted

SQL> insert into cjw_test_bak values('4','1','1');

 

1 row inserted

 

SQL> commit;

 

Commit complete

 

SQL> insert into cjw_test select * from cjw_test_bak;

 

insert into cjw_test select * from cjw_test_bak

 

ORA-04091: table TBCS.CJW_TEST is mutating, trigger/function may not see it

ORA-06512: at "TBCS.TRG_CJW_TEST", line 4

ORA-04088: error during execution of trigger 'TBCS.TRG_CJW_TEST'

 

SQL>