Re: Getting info across databases...

From: Andrus Adamchik (
Date: Thu Nov 18 2004 - 21:05:26 EST

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    And at the same time I confirmed that Michal's problem was the same
    exact case - Dicipline.externalId wasn't a PK. So I simply faked a PK
    column (marked externalId as PK without changing the underlying DB),
    and it started to work..

    Anyway, will need to support this better in the future, so I reopened


    On Nov 18, 2004, at 8:55 PM, Bryan Lewis wrote:

    > That was it! We had a to-many relationship where the key wasn't a
    > primary key in the source table. I'm not sure why... the database
    > design is years old. I switched to using the source pk
    > (add a column to the destination table, populate it, remove the old
    > column) and the problem went away. Thanks! Hope this is helpful to
    > others.
    > Andrus Adamchik wrote:
    >> Bryan,
    >> I pointed out to the known things first ;-)
    >> Another thing that I noticed for CAY-231 (IIRC, need some time to
    >> look at
    >> it for real) was that to-many relationship wasn't based on a source PK
    >> (instead it uses a regular column). This limitation was fixed for 1..1
    >> relationships, but looks like it breaks for 1..n. Could you
    >> doublecheck
    >> that? If this is indeed the problem, I guess we need to reopen
    >> CAY-231.
    >> Andrus
    >>> Hmm, well... it's true that my example didn't have a reverse
    >>> relationship for the to-many at the object level. But when I
    >>> added one just now, it didn't change the problem.
    >>> Andrus Adamchik wrote:
    >>>> Michal,
    >>>> I looked at CAY-231 submitted by Bryan, and I suspect that his
    >>>> problem
    >>>> happens cause to-many object relationship doesn't have a reverse
    >>>> to-one (this is currently a requirement in Cayenne -
    >>>> Is
    >>>> it
    >>>> possible that you have the same situation?
    >>>> Our archiver messed u the XML files you uploaded with the earlier
    >>>> message, so I can't doublecheck this from here.
    >>>> Andrus
    >>>>> Okay here is another quirk that is definetly related, the original
    >>>>> problem I posted created as you know the query
    >>>>> SELECT t0.Disabled, t0.FirstName, t0.LastName, t0.LoginName,
    >>>>> t0.UserId, t0.UnitId FROM dbo._UserInfo t0 WHERE t0.UnitId = NULL
    >>>>> and this was going from
    >>>>> Discipline.externalId -> _UserInfo.UnitId
    >>>>> now there is another relation that links user's to discipline and
    >>>>> that
    >>>>> is a double join table, which I don't flatten.
    >>>>> ->
    >>>>> ProjectDisciplin.disciplineId
    >>>>> ->
    >>>>> ProjectDisciplineUser.projectDisciplineId
    >>>>> ProjectDisciplineUser.userId ->
    >>>>> _UserInfo.UserId
    >>>>> now here's the kicker, when I create a new ProjectDisciplineUser
    >>>>> relationship, it creates but the problem is that it tries to updata
    >>>>> the _UserInfo.UnitId to NULL. Now this is a locked object as it
    >>>>> is on
    >>>>> a seperate live database, so it give me an exception. But the
    >>>>> error
    >>>>> is cause by an UPDATE query that is updating the UserId(to whatever
    >>>>> userId i'm setting) and the UnitId(to NULL).
    >>>>> Now when I remove the link in the cayenne files between
    >>>>> Discipline.externalId -> _UserInfo.UnitId
    >>>>> everything works great. This is the link that created my original
    >>>>> problem/posting. I have a very strong feeling these a related but
    >>>>> I
    >>>>> really don't know why the field would be set to NULL.
    >>>>> Thanks for all this help.
    >>>>> Cheers
    >>>>> Mike
    >>>>> -----Original Message-----
    >>>>> From: Andrus Adamchik []
    >>>>> Sent: Tuesday, November 09, 2004 7:04 PM
    >>>>> To:
    >>>>> Subject: Re: Getting info across databases...
    >>>>> Let me take a look at the bug report. That indeed looks strange.
    >>>>> Thanks for the test case!
    >>>>> Andrus
    >>>>> On Nov 9, 2004, at 12:22 PM, Bryan Lewis wrote:
    >>>>>> I think I can help on reproducing the problem. We ran into the
    >>>>>> same
    >>>>>> issue today with a SQL statement ending in "= NULL", for no good
    >>>>>> reason that we can see. It's a simple one-to-many relationship
    >>>>>> using
    >>>>>> a VARCHAR field as the key.
    >>>>>> I had a good test case from a previous bug report that seemed to
    >>>>>> work
    >>>>>> well for Andrus. I've updated it to cover this case and
    >>>>>> submitted it
    >>>>>> as CAY-231.
    >>>>>> Michal Kozlowski wrote:
    >>>>>>> I feel I'm doing something wrong b/c you couldn't reproduce the
    >>>>>>> problem.

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