db-derby-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Luis Ribeiro <luisribeiro1...@gmail.com>
Subject help with sql query for Derby
Date Fri, 29 Apr 2011 02:22:56 GMT
Dears,
    My name is Luis Ribeiro, I`m brazilian and I study Computer Science at
Universidade Presbiteriana Mackenzie (
http://www.mackenzie.br/portal/principal.php). I and Henrique Teixeira (cc)
are on the last semester and we`re doing our final project. To be honest,
we`re finishing its. It`s about Comparison between HD databases and
In-Memory databases.
    We`re trying to use Apache Derby to know how it works with the simple
systems that we developed.
    We have two doubts and I would be greatfull if you could answer to us:
    - Does exist some function or method that you use similar to
"GROUP_CONCAT" (from MySQL)? I want to know if I can do this on a simple way
with Apache Derby?

Original table
ID | NAME
1  | Luis
2  | Henrique
3  | Luis

After do the query
ID | NAME
1, 3 | Luis
2  | Henrique

    - What we need to do to have a exceptional performance with In Memory
mode? I`d increased jvm heap, but it didn`t work.

    I`m sorry if I was offensive with this e-mail.

    Thank you very much.

Best regards,
Luis Ribeiro

Mime
View raw message