Re: "Can't get primary key from temporary id" :(

From: Aristedes Maniatis (ar..sh.com.au)
Date: Tue Apr 07 2009 - 20:35:17 EDT

  • Next message: Joseph Schmidt: "Re: "Can't get primary key from temporary id" :("

    On 08/04/2009, at 8:26 AM, Joseph Schmidt wrote:

    > Can't get primary key from temporary id
    > ------------
    >
    > while trying to access the 'id' of a newly created object entity A.
    > I need this 'id' to write the value together with some other fields
    > in some other object entity B inside the same transaction. Between A
    > and B there's no relationship (I'm using MySQL as a DB and CayenneM5).

    The primary key doesn't exist until the record is written to the
    database, so you just can't do this. You have two options:

    * write the record to database, fetch it back again and then you'll
    have the primary key
    * create a relationship between A and B

    If you find yourself using the primary keys directly very often, you
    are probably not using Cayenne in the manner it was intended. The idea
    is that it removes you from thinking about database-centric issues
    like primary keys and just think about objects and how they relate to
    each other. Mostly.

    Ari

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