MERGE statement - Source with duplicate values not raising error ora-30926

Question

Hi ,
I'm having a problem with merge that has already been reported in another thread ( Re: MERGE strange behavior ). I created a procedure with a query and have tested inserting two equal values on the Key column to raise the error. But on the first time there i run the Procedure it runs without error, apparently updating with the first row found. On the second time there i run the procedure then Oracle raises the error.
Above you can see the code to simulate the issue:
-- creating the table
create TABLE teste
( ID NUMBER NOT NULL , DESCR VARCHAR2 (20 CHAR) , GRUPO VARCHAR2 (30 CHAR) );
-- inserting the pk in table
ALTER TABLE Teste
ADD CONSTRAINT DimTestec_PK PRIMARY KEY ( ID ) ;
-- inserting records in the table
insert into teste
select -2 AS id,'t-2' AS descr,'t-2g' AS grupo from dual
union all
select -1 AS id,'t-1' AS descr,'t-1g' AS grupo from dual
union all
select 1 AS id,'t1' AS descr,'t1g' AS grupo from Dual
union all
select 2 AS id,'t2' AS descr,'t2g' AS grupo from Dual
union all
select 3 AS id,'t3' AS descr,'t3g' AS grupo from Dual
union all
select 4 AS id,'t4' AS descr,'t4g' AS grupo from Dual
union all
select 5 AS id,'t5' AS descr,'t4g' AS grupo from Dual
--create the procedure to teste the merge
create or replace procedure mergeteste is
Begin
MERGE INTO teste testemerge
USING ( select -2 AS id,'t-2' AS descr,'t-2g' AS grupo from dual
union all
select -1 AS id,'t-1' AS descr,'t-1g' AS grupo from dual
union all
select 1 AS id,'t1' AS descr,'t1g' AS grupo from Dual
union all
select 2 AS id,'t2' AS descr,'t2g' AS grupo from Dual
union all
select 3 AS id,'t3' AS descr,'t3g' AS grupo from Dual
union all
select 4 AS id,'t4' AS descr,'t4g' AS grupo from Dual
union all
select 5 AS id,'t5' AS descr,'t4g' AS grupo from Dual
union all
select 5 AS id,'t6' AS descr,'t6' AS grupo from Dual ) testesource
ON (testemerge.id = testesource.id)
WHEN MATCHED THEN
UPDATE SET testemerge.descr = testesource.descr,
testemerge.grupo = testesource.grupo
WHEN NOT MATCHED THEN
INSERT ( testemerge.id, testemerge.descr, testemerge.grupo )
VALUES ( testesource.id, testesource.descr, testesource.grupo ) ;
commit work;
EXCEPTION
WHEN OTHERS THEN
begin
ROLLBACK;
dbms_output.put_line(dbms_utility.format_error_stack||dbms_utility.format_error_backtrace);
end;
end mergeteste;
-- the first time you execute the procedure, it runs without error - when it shouldn't run cause there's two id with value 5 on the testesource query.
-- the second time it raises the expected error.
Here's the oracle version:
1 Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
2 PL/SQL Release 11.2.0.3.0 - Production
3 CORE 11.2.0.3.0 Production
4 TNS for Linux: Version 11.2.0.3.0 - Production
5 NLSRTL Version 11.2.0.3.0 - Production
Thanks in advance.
Best Regards.
Renan Ribeiro

Answer 1

Hi, Renan,
That sounds like a bug. In Oracle 11.1, I get the error the first time I run the procedure, but in Oracle 11.2, I get the same results you do (that is, no error the first time I run the procedure, error the second time).