db4o Developer Community

I used db4o client/server features and added objects at the server end and committed them. When I try to get those objects in a client program using Native Queries the IList<> always returns 0 objects. Using Query by example I get the desired result.I know my query is right because I tested it on the server program and it works but somehow ...

I don't understand why the execution of a query through a collection, like the following one, must activate all the elements of the collection, if I'm using the identity constrain. Firstly 'pilot' has been retreived from the database. query.Descend(''_pilots'').Constrain(pilot).Identity()Besides, if I try to use Native Query, ...

Hello, I'm using Native Queries and I am very confused with the optimization process, because something like the following query can't be optimized:    Dim etiquetas3 As IList(Of Etiqueta) = BD.Contenedor.Query(Of Etiqueta)(AddressOf QueryEtiquetas)     Public Shared Function QueryEtiquetas(ByVal et As Etiqueta) As ...

One of the key ideas behind db4o is that it should integrate as tightly as possible with the programming language. We are not trying to invent new concepts or new theories, we simply use the ones that are already there, in your programming language. The elegance of what we can deliver varies with what the programming language provides us with. On ...

Hi there,   I am building an application running on db4o 6.4.38.10595 and Java 1.6.02 and I encounter problems regarding Native Query optimization. I added a DiagnosticToConsole-listener which gives me the following error message: :: db4o 6.4.38.10595 Diagnostics ::  Native query not present. :: Native Query Optimizer could not be ...

Hi, In my life of Java development, I have used JDBC to homegrown solutions to EJB to hibernate in various projects.Currently I use hibernate in current application. As a small module, we had a requirement of displaying statistical data and Charts of various types. I had to use pure JDBC for it. Most queries look like: select count(distinct ...

Using db4o 6.4 for java, with single user .yap file or in-memory adapter (i.e., still no c/s).I do have the nqopt and bloat jars on the classpath in ant build file:   <property name=''thirdParty.lib.dir'' location=''${masterbuild.dir}/thirdParty/lib'' description=''dependencies jars'' />  <!-- OO database -->  ...

Hi Ian, You may be enlightened in the explanation here.    Edwin 

Saludos amigos... He estado buscando mis dudas en el foro y de verdad he podido resolver la gran mayoría de ella. Todos los problemas que estoy teniendo veo que no soy el único que se les ha presentado esta serie de inconvenientes. Una duda que tengo es con respecto a Native Query - realmente no me quejo de este tipo de consultas - pienso que ...

Hi,I've made a few posts about my problem with predicates but I think I have the right question to ask now :)I have a simple server application, which does not have any .dll or .xml reference to the objects I am storing. The Test application is seperate to the client test application.My test program has three methods of querying the database, but ...