Marco,
on 1- yes I hear you. If you want to try your hand at extending the JAWS
commands you can... it will take you a couple of hours to please take a
crack at it. If you can't the simplest is probably to use BMP beans.
2- PostgreSQL runs on windows afaik...
regards
marc
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Marco
Sent: Thursday, October 26, 2000 5:12 PM
To: jBoss
Subject: [jBoss-User] Find optime Database for my Job
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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