db4o Developer Community

BilderHerunterlader is a Java software which makes it easier to download hosted images. It's open source (GPL v2) and currently using the following libraries: jtidy, JDom, db4o, log4j, Jakarta-Httpclient, BrowserLauncher, SwingX, ini4j, sqlitejdbc, GUITools, FileIOTools (review, download)

Join Jim Cassidy in his effort to use db4o together with Jython. He suggests an an Active Record like wrapper around db4o. Stay tuned to his blog for upcoming db4o samples implemented in Jython.

As you probably already know :), Sharpen is a tool (developed by db4o) that aims at easing development efforts by translating java source code into C#. This tools make it easier to provide native solutions in either Java/.Net platforms. While talking about how to run Sharpen test suite in this post I told that I'd show how to improve these ...

Graham, Yes thanks for the reply.  I had gotten that far with it, and I wasn't expecting db40 to have some automated migration in this case.  But I was hoping to get more insight into what were some of the best practices for handling this. Say I was going to do the above example, but I wanted to migrate that data forward.  I had read in some of ...

I'm a newbie to db4o so please excuse my newb question, but I'm under a deadline to find out answers quickly.  I have an application written in Java using db4o, and I'm in the process of upgrading between the prior release of my application and my next version of my application.  How can I migrate the object schema from the previous version to the ...

Hi. If you start using sharpen, you'll probably find some limitation / bug and, maybe, want to take a look into the issue. In this case the best approach (IMHO) would be to i) start a discussion in Sharpen Forum and, if appropriated (in the case there's no issue filed already), ii) file a new Jira issue into our issue tracking system. Next, ...

Hi all, I am developing an application with the Java version of db4o and I just ran into a problem: I am able to retrieve the information from a stored object and alter it once, but when I try to alter it again, I get a DatabaseClosedException. I managed to debug the program up to the problem, but am not able to solve it. It follows a short ...

In this post Rodrigo introduced the concept of Transparent Persistence that makes developers life even easier as, once configured, db4o will take care of changed objects and make sure they are updated in the database (when the transaction gets committed) without developer assistance.This level of transparency is, of course, a welcome addition but ...

I'm new to db4o and eclipse, but I created a project that compiles and runs fine in eclipse but when I export the jar file it doesn't export the db4o class that is included so the jar file can't be launched. How do I tell eclipse to create a reference or link to the db4o jar files in order to run the classes outside of the IDE without getting ...

Okay, I finally figured out what the problem was with my NQ in Client/Server.  It basically came down to the anonymous inner class and how DB4O sends the query over the network to the server.  It wasn't able to serialize it correctly, so the query didn't work.  I moved my Predicates out of the dao class and into their own.  ...