Multiple updates to same row

Question

Hi experts,
I still cant figure out how oracle handles multiple updates to the same row. For instance I have 3 update statements:
update supplier set supp_type = 'k' where supp_code = '1';
update supplier set supp_type = 'j' where supp_code = '1';
update supplier set supp_type = 'm' where supp_code = '1';
I keep getting the final result to be supp_type = 'k' where it should actually be 'm', but when i execute the mapping it shows 3 update operations, which baffled me as to how oracle handles simultaneous updates to same row. I even tried disabling parallel dml on the table object, but am unsure whether this actually helps. I try putting a sorter operator and then a key lookup operator after the sorter operator in my mapping to compare the supp_code field in the sorter with the target table's supp_code field to retrieve the relevant row to update, but instead of 3 update operations, it now updates all supp_type in all my records to NULL. Can anyone explain to me how i should go about dealing with this?

Answer 1

Hi experts,
I just took a look at the code section generated for the key lookup operator named SUPPLIER_WH_SURRKEY01 and I feel something is wrong with the generated code. I have pasted the code section on the key lookup operator below.
ORDER BY
"SUPPLIER_CV"."RSID$" ASC ) *"SORTER" ON ( ( ( "SUPPLIER_WH_SURRKEY01"."EXPIRATION_DATE" = "SPIDERWEB2"."GET_EXPIRATI_0_EXPIRATI" ) ) AND ( ( "SUPPLIER_WH_SURRKEY01"."SUPPCODE" = "SORTER"."SUPP_CODE$1" ) ) )*
WHERE
( ( "SUPPLIER_WH_SURRKEY01"."SUPPKEY" IS NULL ) OR ( "SUPPLIER_WH_SURRKEY01"."SUPPKEY" = "SUPPLIER_WH_SURRKEY01"."SUPPKEY" ) );
Can anyone explain to me the codes in bold? I have no clue as to what it means? Furthermore, those bold-ed codes look similar to what I have expected to find in the where clause, except that instead of SUPPLIER_WH_SURRKEY01"."EXPIRATION_DATE" = "SPIDERWEB2"."GET_EXPIRATI_0_EXPIRATI", I expected to find
SUPPLIER_WH_SURRKEY01"."EXPIRATION_DATE" = '31-dec-4000', because my key lookup operator checks upon a constant with the value '31-dec-4000'. And the constant name is CONSTANT itself, while my mapping's name is SPIDERWEB2(not too sure why the generated code refers to my mapping name instead of my constant)
Edited by: user8915380 on 17-Mar-2010 00:52