I'm currently trying out db4o (the java version) and I pretty much like what I see. But I cannot help wondering how it does perform in a real live (web-)environment. Does anyone have any experiences (good or bad) to share about running db4o? ...
I've used db4o with much success on many projects in the past. Over time it seems to have evolved greatly, and with modern trends like LINQ on everyone's tongue it has peaked my interest again, especially now that I know that it is starting to support transparent activation and persistence which intrigue me quite a bit, but a friend pose...
thinking of using an object db in memory, anyone have an opinion on DB4O? ...
I'm very impressed with my initial tests with db4o. However, i'm wondering just how many enterprise class websites are out there powered by db4o, i couldn't see any on the main website? I can't see any reason why db4o should not be used. There appears to be decent enough support for transactions and ways to handle concurrency for examp...
Say you're coding some kind of web application. Something where people can contribute content, e.g. a simple photo-sharing site. How many good reasons can you think of to not go with an object-oriented database (e.g. db4o)? ...
We're evaluating db4o (an OO-DBMS from http://www.db4o.com). We've put together a performance test for client/server mode, where we spin up a server, then hammer it with several clients at once. It seems like the server can only process one client's query at a time. Have we missed a configuration switch somewhere that allows for this ...
I'm using db4o 6.4.54 in OSGi environment as a model storage. Every time I restart OSGi framework, the database appears to be empty, although the file is there and not empty definitely. I have the following configuration: A core bundle, which depends on the standard db4o_osgi bundle provided by db4o. An UI bundle, which depends on the ...
I'm new to OODBMS systems, but I'm using Db4o on a new project for which it's perfectly suited. Things are going great and I really like the concept, but I'm struggling with how to do basic data management tasks associated with development. Periodically I want to wipe out all of a certain Type in the DB, how do I do this without actual...
Am I doing something wrong or is it not possible to specify a generic class as a constraint to a generic method? I have been playing around with generics and db4o (open source object database) and am writing a test program (see code below) to store and retrieve some user defined generic collections. I am attempting to write a generic m...
Since the 7.x versions of db4o ObjectManager are only available as a commercial product (very expensive!) are there any alternative tools that are available to inspect/explore db4o 7.x databases? Also, what other tools would you recommend to a beginning db4o developer? ...
I'm interested in using db4o as my persistence mechanism in my Desktop application but I'm concerned about a couple things. 1st concern: Accidentally clipping very complex object graphs. Say I have a tree with a height of 10 and I fetch the root, how does it handle me storing the root object again? From my understanding, it doesn't f...
In my DB4O database I have an amount of Book objects Book +string: Title ... When entering a title (string) in my form I would like to suggest existing titles. Currently I use a simple book.Title.Contains(titlePart) But it would be a nice adition if I could suggest books with titles that match the input title even if it had se...
When using Db4oFactiory.OpenFile("somename"); it was trying to drop the folder "somename" into the visual studio directory and getting denied permission. I solved this by giving it an absolute path: db = Db4oFactory.OpenFile("E:/test-projects/db4o/db"); and now I'm catching a FileNotFoundException but the db4o docs explicitly...
The following query works. I get the correct result back when I enter the name with a wrong casing. private static IObjectContainer db = Db4oFactory.OpenFile(db4oPath); public static IQueryable<Company> GetCompaniesByName(string name) { return (from Company c in db where c.Name.ToLowerInvariant().Equals(nam...
In linq to sql i can do like this: var q = db.Colors; if(! string.IsNullOrEmpty(colorName)) q = q.Where(c=>c.Name.Equals(colorName)); return q.ToList(); In Db4O linq I can't do it like this because I have to start with var q = (from Color c in db select c); if(! string.IsNullOrEmpty(colorName)) q = q.Where(c=>c.Name.Eq...
We've been trying db4o for persisting objects on the compact framework. It works very well from our tests so far. However, it appears they are on the expensive side for small startups with minimal units needed. Does anyone know of any similar object databases for the compact framework? How about a open source one that is free for comme...
Is there any way to completely disable Java security manager? I'm experimenting with source code of db4o. It uses reflection to persist objects and it seems that security manager doesn't allow reflection to read and write private or protected fields. My code: public static void main(String[] args) throws IOException { System.out....
I have just downloaded and and am using db40 7.9 and am testing it on two different .NET 3.5 applications using the supplied tutorial. When I access the same database (c:\pilot.db4o) file using these two applications, one after the other, each one is reflecting only the changes made by that application, even if those changes were made d...
Hi, I am trying to do standard bi-directional replication as follows. However, I get a NullReferenceException. This is a separate replication project. I did import the classes involved in the original project (such as Item, Category etc.) in this replication project. What am I doing wrong? (If I debug using VS, I can see that changedObj...
What mechanism does db4o use to instatniate stored objects ? My class isn't Serializable and doesn't provide zero argument constructor and the only constructor throws NullPointerException when it's argument is null. In spite of that db4o can still instantiate stored objects of that class (thugh with incorrect values). If I can underst...