We are looking at implementing a persistence layer in a 3-tier app. I like the design that ambler presented in his papers at http://www.ambysoft.com/persistenceLayer.pdf. I especially like the support for adhoc queries and the support for multiple object manipulation. The only thing that makes me nervous is his suggestion to use dynamic sql.
- Posted by: Web Master
- Posted on: March 29 2001 11:16 EST
Does anybody have experience with this design. How much of a performance hit can I expect? I have implemented it on a small scale. But I am unsure about well it scales.
- Scott Ambler Persistence Layer by Stefan Tilkov on March 29 2001 14:34 EST
- Scott Ambler Persistence Layer by Deepak Singh on March 29 2001 16:43 EST
- Scott Ambler Persistence Layer by Pawel Pietrusinski on March 29 2001 19:28 EST
I have not seen Scott's paper, but all commercial persistence layers use, at least AFAIK, dynamic SQL. So I don't think that you should expect to many problems from this design decision.
Well, Have you Tried Toplink for Java which is the Product of WebGain.
Maybe you can try the same.
The use of dynamic versus static sql has negligible
performance implications, and if you pay attention
to how your sql is built the db engine can cache and
reuse parsed queries anyway. (Of course if you
run ad hoc queries then this does not apply, but then
nothing else will help you either..)
Thanks for the responses. Can you point me in the direction of papers or samples that have implemented dynamic sql in Java or EJB.
I am aware of 2 opensource implementation of Ambler's
framework. The one is Artyom Rudoy's "pl" software, the
other is "Osage". I think you can find the links from
Scot Ambler's page where you can dowload the original
papaer from. The Home page is www.ambysoft.com. incze