Project:
1) EDM system.
2) Aproximately 10-40 concurrent users maximum.
3) Need to store a lot of history information and to achive desired performance need to use precalculated data which will be modified if entities connected to it were modified.
4) Also I need to use free databases (MySQL or PostgreSQL etc).
5) System shuld have 3 tiers (not neccessary distributed) clients (web, gui), business logic and db due to use of different clients.

I am not sure whether I can make such mappings using Hibernate. For example when I store record I need to delete cache data and later it will be regenerated during selection (or something like this). Changes happens quite seldom.

Thank you for your help!

1) EDM system.
???

2) Aproximately 10-40 concurrent users maximum.

Hibernate is suitable.

3) Need to store a lot of history information and to achive desired performance need to use precalculated data which will be modified if entities connected to it were modified.

Second-level cache...
http://www.hibernate.org/hib_docs/reference/en/html/performance.html#performance-cache
Native SQL Queries...
http://www.hibernate.org/hib_docs/refer ... rysql.html


4) Also I need to use free databases (MySQL or PostgreSQL etc).

Yeah!!! PostgresSQL, MySQL supported both.

5) System shuld have 3 tiers (not neccessary distributed) clients (web, gui), business logic and db due to use of different clients.

It is your architecture decision, Hibernate does not limit you.


The following app. server JBoss, Weblogic, ect are supported.

I am not sure whether I can make such mappings using Hibernate. For example when I store record I need to delete cache data and later it will be regenerated during selection (or something like this). Changes happens quite seldom.

The following second-level cache politics are supported
<!ATTLIST cache usage (read-only|read-write|nonstrict-read-write|transactional) #REQUIRED>



A Comparison of Hibernate and Toplink http://www.calextech.com/articles.html can be helpful.

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Regards,
Leonid

electronic document management system

Main problem (as I see) is: how (and who) will perfrom update of interim entities.

For example:
I have documents that calculated using data of others types of documents.
To increase performance I need to store precalculated data on specific dates.
To do calculation I need to take [precalculated data on date N] + [calculate data on dates range N+1...CurrentDate] (thus I don't need to recalculate whole history information).
If some documents in date range [0...N] changed I need to update precalculated data.
Calculations are quite complex and connot be implemented using materialized view in RDBMS (MS SQL Server, Oracle, but now I couldn't use these databases anyway :)).

Is it possible to implement this using Hibernate? As I understand hibernate manages objects persistance and I don't understand how to perform side effects.

For side effects:

1). you are still able to use database triggers with session.saveOrUpdate(obj); followed by session.refresh(object);

2) you can use hibernate's cascade save/update operations with configured Interceptors http://www.hibernate.org/hib_docs/reference/en/html/manipulatingdata.html#manipulatingdata-interceptors

Thank you for your help! :)

Nevermind, in addition it seems you are Russian :) Pavel...

Yep!

(About triggers: I think it's better not to use them. There are a lot of problems with them (errors handling, they are static, it's difficult to write and maintain complex triggers)).

In your case I would prefer Interceptor, maybe trigger solution would be faster, but more buggy (error handling, .... and trigger debugging) and not portable to other databases.

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Regards,
Leonid