Hi Alain
We have done exactly this for a summary screen of some mainframe
data. The analysis level component has a large number of historical
lists associated with it, but the common case is to only view the
most recent entry. We have an additional implementation level
component (read-only) as you suggest which presents only this
data. The key to making this work is
DOCUMENTATION
You need to document _why_ you chose to add the additional view at
implentation level, and _who_ is responsible for maintaining the
integrity of the data, and _how_ you enforce these constraints.
Joel
Alain Rogister wrote:
>
> Hi,
>
> Has anyone experimented with the idea of mapping entity beans with RDBMS
> views ?
>
> Imagine that you want to produce summary reports about the contents of
> several large database tables. You'd like to do this through entity
> beans for a number of good reasons like making security checks at the
> entity level and adding some business logic. But if you end up coding
> complex in-memory navigations between entity instances, it's easy to
> imagine horror scenarios involving massively inefficient use of the
> RDBMS.
>
> What about defining a number of (materialized ?) views that would let
> the RDBMS take care of the query processing ? Instead of coding complex
> navigations, you'd create "aggregate" entity beans mapped against
> summary views. Did anyone try this ? I'm thinking mostly of read-only
> views, but updatable views would also be interesting in some scenarios.
>
> Alain.
> --
> Alain Rogister
> Ubiquity s.a.
> http://www.ubiquity.be
>
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