NOTE:
Although using compound keys (custom primary keys) is legal in EJB 1.1 (even for
single fields), a bug in the J2EE RI prevents them from being used. I figured it was
worth mentioning since people depended on the J2EE RI for developing beans. In the
J2EE RI you can only use single-field primary keys.
Richard
--
Richard Monson-Haefel
Author of Enterprise JavaBeans, 2nd Edition
Published by O'Reilly & Associates
http://www.EjbNow.com
Vlada Matena wrote:
> The primary key class MyPK defined below is legal in EJB 1.1. However,
> the "value" field must be defined as "public" in the class.
>
> Vlada
>
> ----- Original Message -----
> From: "Evan Ireland" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Tuesday, April 25, 2000 3:25 PM
> Subject: Re: EJB spec does not permit numbers as primary keys
>
> > "Jonathan K. Weedon" wrote:
> > >
> > > c) Primary Key wrapper classes for single field primary
> > > keys are deprecated in EJB 1.1. This precludes using a
> > > class FooPK as a primary key type.
> >
> > If this is deprecated (although I can see no evidence of it myself) then it
> > is a big mistake.
> >
> > I suspect that it is not deprecated. I would recommend the following pattern
> > for numeric primary keys:
> >
> > public class MyPK
> > {
> > int value;
> >
> > MyPK() { ... }
> >
> > // hashCode and equals ...
> > }
> >
> > This is preferable to using java.lang.Integer as a primary key type as it gives
> > you better type safety (you can't accidentally pass an AccountKey where a
> > CustomerKey is expected).
> >
> > <vendor>
> > We also permit entity components to have non-valuetype primary keys in our
> > product, but the mechanism is proprietary and so we leave it undocumented.
> > </vendor>
> > ________________________________________________________________________________
> >
> > Evan Ireland Sybase EAServer Engineering [EMAIL PROTECTED]
> > Wellington, New Zealand +64 4 934-5856
> >
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> >
> >
>
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