RE: JDBC Data Source - Data Access Beans

["DUCRET Gilles (GVA)" <Gilles.DUCRET@xxxxxxxxxxxxx>]

Title: RE: JDBC Data Source - Data Access Beans

I think that the main advantage with Data beans provided by IBM is
not really the caching, but the programmatic facilities.

You have a "JDBC2 like" way of accessing data. The caching is one more functionnality,
but it is the caching of the content of one result set, not a table. The interesting thing
in this case is that you don't have to hold the result set, the statements, etc ...
(but you cannot release the connection)

What we do here: we access data using stored procedure (we use the data beans functionnalities to
read the results). We can manage performance issues at the stored proc level (loading, etc ...)
We only cache read only objects (in a cache for business objects), but not the lists.
The performance are good and we don't have to manage any consistency between the state of an object
and the database.

-----Original Message-----
From: David Morris [mailto:dmorris@plumcreek.com]
Sent: mardi, 3. juillet 2001 21:36
To: JAVA400-L@midrange.com
Subject: RE: JDBC Data Source - Data Access Beans

Gilles and others,

You mention the Data Access Beans, which are probably not an option in our application. 
What are some of the alternatives?  I have built a set of beans that support relatively
stable files for our system.  I doubt I did this optimally.  In our case, I used a keys to data
values.  I also included an expired flag.  The first person to hit a file will load the data. 
If a table changes, the expired flag is set. This data does not change very often at all
(most files have been in production with no data changes for over 5 years).  I did have
to make an assumption that is OK for now that as long as you are authorized to the
application you are authorized to this master file type data.

I can see some drawbacks to my design particularly with larger files.  The largest
in this case is only about 3000 records.  So far that has not been a problem, but
it would be nice to have a more selective cache. Another problem would be if
it becomes necessary to lock down individual files.  Most of these beans support
custom tags used in the user interface that uses Struts to control the view.

David Morris

>>> Gilles.DUCRET@lloydsbank.ch 07/02/01 01:27AM >>>
...I suggest you to use the Data Access Beans provided by IBM. They have
caching features allowing you to read the result set even if
it is closed (In fact you don't read the resultset, but a cache object
containing the result).
 
Gilles

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