Re: Primary Key question

From: Scott McClure (scot..martblob.com)
Date: Fri Jul 23 2004 - 07:00:48 EDT

  • Next message: Dirk Wellmann: "Re: Primary Key question"

    What if I want my ID column to exist in the object entity? I have the
    necessary tables set up (through modeller).

    Scott

    Dirk Wellmann wrote:

    >Hello Scott,
    >
    >to get the ID generated by cayenne, you first have to add a row to the Table
    >"AUTO_PK_SUPPORT". You could create a SQL-Statement with the Modeller
    >Tools->GenerateDatabaseSchema at the bottom you will find a create table and an
    >Insert for your Table. Before you do that, you have to remove the Objectentity
    >for your ID-Column. PK-Columns only have to exist as DB-Entity. ..ndrus: Am i
    >right?)
    >
    >Regards
    >
    >Dirk
    >
    >
    >Your Mail from Thu, 22 Jul 2004 14:33:10-0400(Scott McClure[Scott
    >McClure<scot..martblob.com>]):
    >
    >
    >>I would like Cayenne to be responsible for generating the ID. What would need
    >>to be done to accomodate that?
    >>
    >>Scott
    >>
    >>Quoting Eric Schneider <eri..entralparksoftware.com>:
    >>
    >>
    >>
    >>>>I have an ID field that I use outside of Cayenne - the field is used
    >>>>for
    >>>>indexing and such, and therefore needs to be a presistent attribute. I
    >>>>want to
    >>>>know if this is possible without modifying the generated class like
    >>>>described
    >>>>in the documentation. I currently have the id attribute set as the
    >>>>primary key
    >>>>in the modeler and also mapped to the object entity. Will this work?
    >>>>
    >>>>
    >>>If Cayenne isn't responsible for generating the id, it will work fine.
    >>>
    >>>
    >>>
    >>>>Second - if I need to find an object by primary key and I have it
    >>>>mapped to the
    >>>>object entity, is it faster to do a query or to use the new utilities
    >>>>in
    >>>>DataObjectUtils?
    >>>>
    >>>>
    >>>Probably DataObjectUtils is the way to go. Any code you don't have to
    >>>write yourself is always good.
    >>>
    >>>cheers,
    >>>eric
    >>>
    >>>
    >>>On Jul 22, 2004, at 11:32 AM, Scott McClure wrote:
    >>>
    >>>
    >>>
    >>>>There has been lots of conversation on primary keys lately - a couple
    >>>>questions.
    >>>>
    >>>>I have an ID field that I use outside of Cayenne - the field is used
    >>>>for
    >>>>indexing and such, and therefore needs to be a presistent attribute. I
    >>>>want to
    >>>>know if this is possible without modifying the generated class like
    >>>>described
    >>>>in the documentation. I currently have the id attribute set as the
    >>>>primary key
    >>>>in the modeler and also mapped to the object entity. Will this work?
    >>>>
    >>>>Second - if I need to find an object by primary key and I have it
    >>>>mapped to the
    >>>>object entity, is it faster to do a query or to use the new utilities
    >>>>in
    >>>>DataObjectUtils?
    >>>>
    >>>>Thanks!
    >>>>
    >>>>Scott
    >>>>
    >>>>
    >>>>
    >>>
    >>>
    >>
    >>
    >>
    >>
    >>
    >
    >
    >
    >



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