db4o Developer Community

Hi, I've been looking at using db4o in a project I'm working on.  This will be a client / server design.  I wanted to prevent deletes of an object if any child objects exist.  I see that the deleting() and deleted() events must be registered with the ObjectServer.  It appears that when the client attempts to delete an object ...

Hi, To support referential integrity I registered listener on event deleting object SProducer. If some other objects in database have references to it deleting will be cancel. ObjectContainer oc = objectServer.ext().objectContainer();final EventRegistry registry = EventRegistryFactory.forObjectContainer(oc); registry.deleting().addListener(new ...

Hallo, I modified the example from Carl Rosenberger (http://developer.db4o.com/forums/thread/40259.aspx)into the appended one [1] The database file will increase (approx. 100kb) on every restart of the program.You can say: oh please use File.delete, but this does not work easily for client/server mode. Do you know a good solution for c/s? ...

Hello, I still got problems to get all the elements of Db4o aware collections deleted. I attached a very simple Test case. Hope this bug can be fixed. //File ListTest.javaimport com.db4o.Db4o;import com.db4o.ext.ExtObjectContainer;import junit.framework.TestCase;import java.io.File;import java.util.ArrayList;import java.util.Date;import ...

I supplied a patch to jira: http://tracker.db4o.com/browse/COR-607 

and how can I delete a blob in client / server mode, where I don't have the file handle of the blob file stored on the server?

Hi,  I'm new to db4o and have a question on the update behavior in the following situation. Suppose the following:  There s a class with Sales persons. Each sales person visits customers. The database contains therefore 3 classes: Customer Visit SalesPerson In the Visit class a reference to the SalesPerson who made the visit is ...

I am unable to commit Delete() operations...I guess that I must be missing something fundamental... I am using db4o(6.1 latest release) in embedded mode. I get a reference to the server from a Singelton wrapper class (ServerRegistry).Another class (ObjectContainerPool) creates any number of clients to my server. If I use only one client my code ...

It seems that when I query for an object which is already known to db4o, the result is taken from the cache regardless of the fact that the cache might be inconsistent with the database. For example - Create two objects, the first referencing the second - Store the objects and commit - Delete the second object from the database and ...

srdemart: After further thinking about it, I think this may not be a problem if the ''Deleting'' callback is called on the client.  I assume if I cancel, then no delete request would be sent to the server.  Am I correct with this assumption? No. All delete callbacks will happen on the server. Still, the impact of a single delete ...