Now in EJB 2.0 it would be much easier to implement immutable primary keys
in the CMP environment because of the abstract persistence schema. The
implementation class could throw an exception on change of primary key
fields. Do you guys think this should be done, or still left open?
Personally I'd like some option to go either way.
Cheers
Jay
-----Original Message-----
From: Cedric Beust
To: [EMAIL PROTECTED]
Sent: 4/4/01 4:57 PM
Subject: Re: EJB 1.1 and change of primary key values
> From: Dave Wolf
> Its an interesting question whether the pk is semantically immutable.
I
> dont see the spec every lay this out as a requirement. Secondly, if
we're
> persisting to an RDBMS which 90% of people are, the RDBMS does
actually
> allow updates on the PK field. So this PK mutability can occur
actually
> outside the EJB and bring about the same issue. Since neither EJB nor
the
> RDBMS enforce the relational models view that nothing changes the PK
value
> (a natural key) then how can we assume it is immutable?
Because it doesn't make sense otherwise? :-)
For example, Hashtable doesn't specify that equals()/hashCode() need to
return the same value after the object has been stored in the table, but
the
behavior is unpredictable if they don't.
Not hard to extend this consideration to PK's.
Be nice to the container and the container will be nice to you :-)
--
Cedric
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