Re: Select Query on Table with no Primary Key

[Craig L Russell]

Just FYI, when JDO reads data from tables without PK, it internally creates a unique id, similar to a generated PK, for the objects that it reads and these ids are discarded when no longer needed. The fact that the mapping is for tables without PK is known by the code that creates the temporary ids.

Craig

On Jun 7, 2007, at 2:33 AM, Dave Merrin wrote:

OK, I've stepped through the code and got to the ObjectResolver. In there it checks for primary keys and throws an exception if there aren't any. Is there any way I can override this code easily to removed the primary key check?

           boolean resolveInheritanceHierarchy) {
       init(context, entity, refresh, resolveInheritanceHierarchy);
   }

   void init(
           DataContext context,
           ObjEntity entity,
           boolean refresh,
           boolean resolveInheritanceHierarchy) {
       // sanity check
       DbEntity dbEntity = entity.getDbEntity();
       if (dbEntity == null) {
           throw new CayenneRuntimeException("ObjEntity '"
                   + entity.getName()
                   + "' has no DbEntity.");
       }

       this.primaryKey = dbEntity.getPrimaryKey();
       if (primaryKey.size() == 0) {

                   + entity.getName()
                   + "'. Reason: DbEntity '"
                   + dbEntity.getName()
                   + "' has no Primary Key defined.");
       }

       this.context = context;
       this.cache = context.getObjectStore().getDataRowCache();
       this.refreshObjects = refresh;
       this.entity = entity;

       this.resolveInheritance = (inheritanceTree != null)
               ? resolveInheritanceHierarchy
               : false;
   }
Michael Gentry wrote:

ObjectResolver(DataContext context, ObjEntity entity, boolean refresh, throw new CayenneRuntimeException("Won't be able to create ObjectId for '" this.inheritanceTree = context.getEntityResolver ().lookupInheritanceTree(entity);

The only thing I can think of trying (and maybe Andrus/Tore/Mike/ etc would have better ideas) is to model that ObjEntity (and perhaps others it relates to?) as read-only and see if Cayenne stops caring about missing a PK. Just

a thought -- I've not tried it.

/dev/mrg


On 6/6/07, Dave Merrin <[EMAIL PROTECTED]> wrote:

like to move round the database using relationships though.


round this problem.

Cheers,

Dave

Michael Gentry wrote:

> data,
> you might try fetching as data rows instead of CayenneDataObjects.
> I'm not

you
> still won't be able to make a CayenneDataObject out of it.
>
> /dev/mrg
>
>
> On 6/6/07, Dave Merrin <[EMAIL PROTECTED]> wrote:
>>
>> Hi,
>>
>> I'm trying to run a SelectQuery on a table with no primary key.

over
>> the database so I can't add in primary keys.
>>
>> Cheers,
>>
>> Dave
>>
>> INFO  QueryLogger: SELECT t0.ID, t0.KIND, t0.TIMESTAMP FROM
>> MPS.STATETABLE_CPT t0
>> INFO  QueryLogger: === returned 949 rows. - took 203 ms.
>> INFO  QueryLogger: +++ transaction committed.

>> [v.2.0.3 May 6 2007] Won't be able to create ObjectId for

>> defined.
>>         at

>>         at

>>         at
>>

>>
>> DataDomainQueryAction.java:319)
>>         at
>> org.apache.cayenne.access.DataDomainQueryAction.execute(
>> DataDomainQueryAction.java:116)

>> :746)
>>         at
>> org.apache.cayenne.util.ObjectContextQueryAction.runQuery(
>> ObjectContextQueryAction.java:217)
>>         at
>> org.apache.cayenne.access.DataContextQueryAction.execute(
>> DataContextQueryAction.java:54)
>>         at

>>         at

:1376)
>>
>>         at

>> :158)
>>         at

>>
>

Sorry, I forgot to mention that I won't be updating the data. I would Apart from changing the database are there any hacks I could try to get > Cayenne needs PKs in order to do UPDATEs. If you aren't modifying the > certain if that would work, but has a much higher chance. Of course, >> Unfortunately it's not working. Can anybody help? I have no control >> Exception in thread "main" org.apache.cayenne.CayenneRuntimeException: >> 'StatetableCpt'. Reason: DbEntity 'STATETABLE_CPT' has no Primary Key >> org.apache.cayenne.access.ObjectResolver.init (ObjectResolver.java:75) >> org.apache.cayenne.access.ObjectResolver.<init> (ObjectResolver.java:57) org.apache.cayenne.access.DataDomainQueryAction.interceptObjectConve rsion( >> at org.apache.cayenne.access.DataDomain.onQuery (DataDomain.java >> org.apache.cayenne.access.DataContext.onQuery(DataContext.java: 1387) >> org.apache.cayenne.access.DataContext.performQuery (DataContext.java >> ipa.printexpress.datahelpers.Session.fetchEntityCollection (Session.java >> ipa.px.importer.abb.ABBImporterMain.main(ABBImporterMain.java: 109)

Craig Russell
Architect, Sun Java Enterprise System http://java.sun.com/products/jdo
408 276-5638 mailto:[EMAIL PROTECTED]
P.S. A good JDO? O, Gasp!

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