Question

THere is a oracle query that I am trying to recreate using OpenJPA. I am writing a service in Websphere integration developer, and I am using OpenJPA as my ORM tool of choice. Previously this query was performed using a stored proc, a ref cursor was used and the information was retrieved like that. Now we are trying to use OpenJPA as our tool of choice. So I am thinking that I should then reconstruct the stored proc using OpenJPA…

SELECT DISTINCT
   P.col1 as ID,
   P.col2,
   P.col3,
   P.col4,
   P.col5,
   S.col6,
   PC.col7,
   P.col8,
   A.ADDRESS_1,
   A.ADDRESS_2,
   A.ADDRESS_3,
   A.CITY,
   A.COUNTY,
   A.STATE,
   A.ZIP_CODE,
   P.CONFIRMED_BY,
   P.CONFIRMED_DATE,
   P.MOD_USERID,
   P.MOD_DATE
FROM   EPCD13.PROVIDER P, EPCD13.provider_channel PC, EPCD13.provider_channel_link pcl,
   EPCD13.provider_specialty ps, EPCD13.SPECIALTY S, EPCD13.Address A, EPCD13.ADDRESS_LINK AL
WHERE P.RESOURCE_ID = personID
  AND P.RESOURCE_ID = PS.RESOURCE_ID (+)
  AND 1 = PS.PRIMARY_SPECIALTY_ID (+)
  AND PS.SPECIALTY_ID = S.SPECIALTY_ID (+)
  AND P.RESOURCE_ID = PCL.RESOURCE_ID (+)
  AND PCL.PROVIDER_CHANNEL_ID = PC.PROVIDER_CHANNEL_ID
  AND 1 = PCL.PREFERENCE (+)
  AND 9 = pc.channel_type_id (+)
  AND PC.CHANNEL_ADDRESS NOT LIKE '%@%'
  AND P.RESOURCE_ID = AL.RESOURCE_ID (+)
  AND AL.ADDRESS_ID = A.ADDRESS_ID (+)
  AND 1 = A.ADDRESS_TYPE_ID (+) 
  AND 1 = AL.PREFERENCE (+);

Notice all those inner Joins and so forth. I am thinking right now of putting a named query in one my methods that will return the same results as above. As you may note, there are multiple tables that are being called there and joined at various points… I am thinking I can just put this query into the createNamedQuery() function with minor changes… But I am thinking there has to be a simpler way to do this? Maybe not. Can I just call a stored proc using JPA?

Answer 1

You can create a JPA entity for each table and then join the entities by doing something similar to this:
http://openjpa.apache.org/builds/1.1.1-SNAPSHOT/docs/jpa_overview_mapping_full.html
Look at the @OnetoMany and @ManytoOne and @ManytoMany annotations in the example for some ideas.