I think a better solution would be for you to just write some of
the finders yourself. You can do that, even with CMP beans, and it will
be *way* faster than waiting for complex features to be added to the core
server.
Aaron
On Thu, 26 Oct 2000, Marco wrote:
> I'm involved in a project using Windows 2K, JBoss and a Database. I'm in trouble
>because few stuffs don't work like I want.
> I need a free Database that offers concurrent access and nested queries. I built my
>multi-tier application using InstantDb since my need of a concurrent access was born
>later.
> But InstantDb was too slow and I wanted to change. I used Hypersonic SQL and mySql
>but both of them don't allow nested queries. This is a trouble for me 'cause in JBoss
>I can't use COUNT, MAX, MIN seen that I can write only where clause and order by
>section in queries.
> In order to fix this trouble I changed my queries using structures like the
>following: instead of
> -- SELECT MAX(fieldname) FROM tablename -- that can not be set in finder methods,
> I used
> -- SELECT fieldname FROM tablename WHERE fieldname = (SELECT MAX(fieldname) FROM
>tablename) --
> that can be!
> But when I changed database, using Hypersonic and mySql, I discovered I can use that
>kind of queries with new databases.
> So I have two different solution:
> 1) Ask you to extend tags in finder methods in jaws files in order to support use of
>MAX, MIN, COUNT, DISTINCT, etc. In this way JBoss shoul offer a way to build the
>first section of sql statements too!
> I think it should not be an impossible stuff! In this way I could came back to use
>first statement I wrote with every database I want! Let me know if you agree with me
>when I say it should be a good improvement. Lat me also know if you need an hand in
>doing this!
> 2) Change Database
> I tried to do this but I had this troubles with:
> JDataStore: there's no mapping in defaultjaws.xml;
> Oracle: it's free for developer but hard to install and configure! And I don't have
>all of this time!
> DB2: I think its too hudge!!
> PostgreSQL: Does a version for Windows exist?
> And I don't know anything about their performances. Of course I want to improve my
>application performances!!! What do you reccommend to me? What database do you think
>I should use? What about other databases you offer type-mapping for in defaultjaws?
>
> Let me know if you have any idea that could be interesting for me.
> Thank a lot,
>
> Eng. Marco Pappalardo
> Ergotech System Inc.
>
>
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