Second Before Trigger Does Not See Value Of CLOB Modified In First Before Trigger
Last updated on MARCH 23, 2015
Applies to:
Oracle Database - Enterprise Edition - Version 10.1.0.3 to 11.1.0.7 [Release 10.1 to 11.1]Information in this document applies to any platform.
Symptoms
If there are 2 before triggers, the second trigger wipes out any lob outbind set by the first trigger.
After trigger 1 modifies the value of a lob column, this lob is passed into trigger 2.
On exit from trigger 2 the original value for the lob column is then passed into the insert (or update), not the value modified by trigger 1.
Example
set echo on;
set serveroutput on;
drop table tab1;
create table tab1 (c2 CLOB);
create or replace trigger tab1_trg1 before insert or update on tab1
referencing old as old new as new
for each row
begin
:new.c2 := 'def';
end;
/
create or replace trigger tab1_trg2 before insert or update on tab1
referencing old as old new as new
for each row follows tab1_trg1
begin
dbms_output.put_line(:new.c2);
end;
/
commit;
insert into tab1 values ('abc');
select * from tab1;
C2
--------------------------------
abc
REM The second trigger tab1_trg2 does not change the value
REM So c2 should have value 'def', instead is has value 'abc'
REM If we drop trigger tab1_trg2 it works correctly.
REM If we do not read :new.c2 in tab1_trg2, it works correctly.
set serveroutput on;
drop table tab1;
create table tab1 (c2 CLOB);
create or replace trigger tab1_trg1 before insert or update on tab1
referencing old as old new as new
for each row
begin
:new.c2 := 'def';
end;
/
create or replace trigger tab1_trg2 before insert or update on tab1
referencing old as old new as new
for each row follows tab1_trg1
begin
dbms_output.put_line(:new.c2);
end;
/
commit;
insert into tab1 values ('abc');
select * from tab1;
C2
--------------------------------
abc
REM The second trigger tab1_trg2 does not change the value
REM So c2 should have value 'def', instead is has value 'abc'
REM If we drop trigger tab1_trg2 it works correctly.
REM If we do not read :new.c2 in tab1_trg2, it works correctly.
Cause
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