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From tgallag...@mmm.com
Subject New Feature Idea
Date Thu, 03 Nov 2011 22:21:49 GMT

I've been working the JDO for about 6 months now.  Prior to that I was 
accessing an RMDBs using a tool I created that built JavaBeans to 
represent the DB tables and to manage those tables. I would then build the 
business logic on top of that.  Using JDO will allow me to expand the 
datastores that I can interact with.  However, moving to JDO means that I 
have to again build a feature I use for about 95% of my DB interaction - 
Query-By-Example (QBE)

With my previous methods, the JavaBeans kept track of items within the 
beans that have changed.  Whenever I wanted to query a table, I would 
create a JavaBean related to the table, set a few values within the bean 
and then user a general query mechanism that would look a the bean, build 
the required SQL and execute it.  This has been useful for about 95% of my 
DB interaction and greatly reduced the amount of SQL written into the 
business layer.

Moving to JDO, I no longer have that.  However, I have built that same 
mechanism into my JDO related JavaBeans.  Using JDO I was further able to 
create generic QBE methods for using subqueries,  something I could not do 

Granted, QBE, does have its limits in that creating a this-or-that kind of 
query is difficult.  My current QBE is limited to "these values" types of 
queries (eg. querying a table based on the table's record id) or, for 
String values, using "Like" functionality.  But my experience with 
database interaction for the last decade is that this covers the vast 
majority of the queries.

I would like to discuss this further with you to determine who this kind 
of functionality can be included in the spec so that I don't have to keep 
re-inventing it with every new datastore access technology.  I can show 
you examples of what we do here at 3M and go over what is required to make 
this work.

Tim Gallagher

Clinical & Economic Research
3M Health Information Systems
5000 Buttercup Drive
Castle Rock, CO 80109

Phone: (303) 814-3867

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