Good point, thanks Victor!
-----Original Message-----
From: A mailing list for Enterprise JavaBeans development
[mailto:[EMAIL PROTECTED]]On Behalf Of Victor Langelo
Sent: 24 August 2000 16:10
To: [EMAIL PROTECTED]
Subject: Re: Multiple Entity components, one DB table
Phil,
There won't be a problem unless your database's locking is too granular.
More important, is why do you want to make lookup values entities? Why not
have a stateless session bean which returns the appropriate lookup object(s)
(id, description, value) directly from the DB or from an in memory cache?
You can provide methods in this bean add/remove objects which updates both
the cache and
the DB. This is a lot more efficient that entity beans for frequently used
but seldom updated data.
--Victor Langelo
Phil Lewis wrote:
> Is this OK?
>
> The reason I ask , is that in our physical DB schema we have a 'lookup'
> table with a structure like:
>
> lupID
> lupType
> lupDescription
> lupValue
>
> This is used throughout a legacy system for storing general data values.
For
> example, several combo boxes available in the UI have configurable
comtents.
> A typical example would be a 'severity' combo. The app allows an admin
user
> to specify the values to list in this combo. This is done by modifying
> lookup entries with a particular lupType.
>
> We are now developing a EJB app that will use the same DB schema, and it
> seems to me that there is a possible argument for treating each of the
> lupTypes as different Entity components. From a component modelling point
of
> view, this makes a lot of sense.
>
> For example, we would want an entity component called
InternetSearchEngine,
> and another called SeverityValue. In future applications of the
components,
> they may mapo onto different tables, but in the current implementaion,
they
> would both map onto the same database table, one with a lupType of (eg) 1,
> and onther with a lupType of (eg) 2.
>
> So, that's why I want to do it, the question is, that it seems to me that
it
> may not be a good idea to have differnt entity beans looking at the same
> table. We are to be using bean managed persistence, but container managed
> transactions. We are developing to the J2EE spec, in an effort to maintain
> app server independence, and so cannot take advantage of any vendor
specific
> facilities.
>
> Is this an advisable course of action, or should I stick with a single
> LookUpValue entity?
>
> Thanks
>
> Phil
>
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