DB Adapter wizard – WHERE clause on parent and child tables not working.

Question

I have two tables, SECURITY and SECURITY_POSITIONS, where SECURITY has a 1:M relationship with SECURITY_POSITIONS. I used the DB-adapter wizard to create the relationship and the following WHERE clause expression which is looking at both the parent and the child tables;
The expression builder looks like this:
AND
|--- 1. partitionKey EQUAL p_SearchKey
|--- 2. securityType EQUAL “DBT”
|--- 3. securityPositionsCollection.dealReference EQUAL “NA”
The primary key on SECURITY = PARTITION_KEY and SECURITY_REFERENCE
The foreign key from SECURITY_POSITIONS to SECURITY = PARTITION_KEY and SECURITY_REFERENCE
securityType is on SECURITY table (master)
securityPositionsCollection.dealReference is on SECURITY_POSITIONS table (child)
The invoke on the database adapter is selecting a row in securityPositionsCollection for each child row, rather than just those with dealReference = “NA”!
I turned on DEBUG logging in the BPEL console and I can see that there are 2 SELECT queries run (guess this is how Toplink does it!), where the 1st query appears to select the parent rows and the 2nd query selects the child rows.
However the 2nd query is not working because it is failing to select only those child rows where dealReference = “NA”. Also, don’t know why the 2nd SELECT query needs to specify the child SECURITY_POSITIONS table twice in the FROM clause, because that seems to be causing the problem.
1st query executed is as follows;
SELECT DISTINCT t0.PARTITION_KEY, t0.SECURITY_REFERENCE, t0.SECURITY_TYPE
FROM CENTRAL.SECURITY t0, CENTRAL.SECURITY_POSITIONS t1
WHERE ((((t0.PARTITION_KEY = ?) AND (t0.SECURITY_TYPE = ?)) AND (t1.DEAL_REFERENCE = ?)) AND ((t1.SECURITY_REFERENCE = t0.SECURITY_REFERENCE) AND (t1.PARTIT
ION_KEY = t0.PARTITION_KEY)))
bind => [200706200000, DBT, NA]
2nd query executed is as follows, where child table appears twice! ;
SELECT DISTINCT t0.DEAL_REFERENCE, t0.PARTITION_KEY, t0.SECURITY_REFERENCE
FROM CENTRAL.SECURITY_POSITIONS t0,
CENTRAL.SECURITY_POSITIONS t2,
CENTRAL.SECURITY t1
WHERE ((((t0.SECURITY_REFERENCE = t1.SECURITY_REFERENCE) AND (t0.PARTITION_KEY = t1.PARTITION_KEY)) AND
(((t1.PARTITION_KEY = ?) AND (t1.SECURITY_TYPE = ?)) AND
(t2.DEAL_REFERENCE = ?))) AND
((t2.SECURITY_REFERENCE = t1.SECURITY_REFERENCE) AND
(t2.PARTITION_KEY = t1.PARTITION_KEY)))
bind => [200706200000, DBT, NA]
Anyone experienced the same problem e.g. why is toplink making the query more complicated that it needs to be, because the query only needs to reference the SECURITY_POSITIONS table once, as follows;
SELECT DISTINCT t0.DEAL_REFERENCE, t0.PARTITION_KEY, t0.SECURITY_REFERENCE
FROM CENTRAL.SECURITY_POSITIONS t0,
CENTRAL.SECURITY t1
WHERE ((((t0.SECURITY_REFERENCE = t1.SECURITY_REFERENCE) AND (t0.PARTITION_KEY = t1.PARTITION_KEY)) AND
(((t1.PARTITION_KEY = '200706200000') AND (t1.SECURITY_TYPE = 'DBT')) AND
(t0.DEAL_REFERENCE = 'NA'))) AND
((t0.SECURITY_REFERENCE = t1.SECURITY_REFERENCE) AND
(t0.PARTITION_KEY = t1.PARTITION_KEY)))

Answer 1

Hello,
It looks like you have configured your 1:M relationship to use batch reading. This causes the query to bring in the Security_Position table's objects to use the same selection criteria as was used on the initial query, with a join statement. This is more efficient in most cases as it ensures only the Security_positions needed for the Security objects to be fully built are read, in a single query.
The selection criteria added is only used to filter out the Security objects. All referenced Security_Positions must be read in for the returned Security objects so that the data matches what is in the database. If you do not want the Security_Positions, you might try using indirection on the mapping which will delay the second query until you need the Security_Positions. Or, if you want only the Security_Positions with dealReference EQUAL “NA", you could do a query specifically to filter on them.
Best Regards,
Chris