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From Pierre Lavignotte <pierre.lavigno...@gmail.com>
Subject Re: How to create Meaningful Primary Keys?
Date Mon, 02 Feb 2009 13:21:17 GMT
Here is what I use when I want to get Recomaster entity with primary key =
id :

        Recomaster recomaster = (Recomaster)
DataObjectUtils.objectForPK(context, Recomaster.class, id);

And in the Recomaster class, I also have a method that gives me the primary
key :

    public Integer getId() {
        return DataObjectUtils.intPKForObject(this);
    }

There are similar methods for when primary key is not an integer value.

Cheers

Cordialement,
Pierre Lavignotte
Ingénieur Conception & Développement
http://pierre.lavignotte.googlepages.com


On Mon, Feb 2, 2009 at 2:14 PM, Νίκος Παράσχου <niparasc@gmail.com> wrote:

> First of all thank you for your replies.
>
> I have the following table:
>
> Vehicle (
>       plate_num CHAR(10) NOT NULL,
>       mixed_weight DOUBLE PRECISION NOT NULL,
>       type CHAR(30) NOT NULL,
>       manufacturer CHAR(20),
>       PRIMARY KEY (plate_num)
> )
>
> In Cayenne Modeller I have the dbEntity "vehicle" with all the above
> attributes (plate_num is check as PK). There is also the objEntity
> "Vehicle" with all the above attributes except the PK (plate_num).
>
> I want to select the type of the vehicle with plate_num = "AHZ-4141".
>
> Could you please post some code samples? I have tried so many things
> (with DataObjectUtils too) but still no success.
>
> Thank you,
> Nikos
>
> Στις 02-02-2009, ημέρα Δευ, και ώρα 12:49 +0100, ο/η Pierre Lavignotte
> έγραψε:
> > Hi Nikos,
> >
> > If you need PK for all your tables, then maybe you need to generate them.
> > But if you only need to use them for a couple tables then you should look
> at
> > DataObjectUtils class.
> >
> >
> > Cheers,
> > Pierre
> >
> > Cordialement,
> > Pierre Lavignotte
> > Ingénieur Conception & Développement
> > http://pierre.lavignotte.googlepages.com
> >
> >
> > On Mon, Feb 2, 2009 at 12:35 PM, Νίκος Παράσχου <niparasc@gmail.com>
> wrote:
> >
> > > Hello,
> > >
> > > It is the first time I am using cayenne and I have some questions
> > > regarding the primary keys.
> > >
> > > What I want to do is select some rows of a table where the PK has a
> > > specific value. The problem is I can't access the PK. I can specify
> > > qualifiers only with the non-PK columns. The PKs I am using have some
> > > meaning (they are not just numbers) so it is very important to be able
> > > to use them.
> > >
> > > How can I add the PK to the fields of the Object Entities?
> > >
> > > In this page
> http://cayenne.apache.org/doc20/primary-key-generation.html
> > > the answer is to create a Meaningful Primary Key.
> > >
> > > How can I create Meaningful Primary Keys?
> > >
> > > Are there any security issues when using Meaningful Primary Keys?
> > >
> > > Thank you for your time,
> > > Nikos
> > >
> > >
>
>

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