db4o

问题 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 example. Anyone got a list of websites i could look at? 回答1: See: http://developer.db4o.com/Projects/html/projectspaces/gaabormarkt.html 回答2: A particular search

问题 Apparently the db4o website was recently redone, and now old urls are giving 404 errors. Everytime I think I've found the answer, I get a 404 error. I have a simple db4o database I've setup to store people. public class Person { public string Firstname { get; set;} public string Lastname {get;set;} } I've been able to run Linq queries on the database, and everything works wonderfully. I'm programming in a web environment, so I will need someone to identify and fetch unique objects from the

问题 I'm creating a db4o object (namely Customer.yap) and if it is already created i just insert new objects into the existing object (namely Customer.yap) . For both these operations i'm just using: IObjectContainer db1 = Db4oEmbedded.OpenFile(Db4oEmbedded.NewConfiguration(),@"C:\Users\admin\Desktop\Db4oObjectFiles\Components.yap"); try { db1.Store(comp1); } finally { db1.Close(); } Am i doing it right or is there a separate command to check if the object exists and then insert values or can i

问题 Our database includes 4,000,000 records (sql server) and it's physical size is 550 MB . Entities in database are related each other as graph style. When i load an entity from db with 5 level depth there is a problem (all records are loaded). Is there any mechanism like Entity Framework( Include("MyProperty.ItsProperty")) What is the best Types for using with db4O databases? Is there any issue for Guid, Generic Collections? Is there any best practise for WebApplication with db4o? Session

问题 OutOfMemoryError caused when db4o databse has 15000+ objects My question is in reference to my previous question (above). For the same PostedMessage model and same query. With 100,000 PostedMessage objects, the query takes about 1243 ms to return first 20 PostedMessages. Now, I have saved 1,000,000 PostedMessage objects in db4o. The same query took 342,132 ms. Which is non-linearly high. How can I optimize the query speed? FYR: The timeSent and timeReceived are Indexed fields. I am using

问题 I am currently testing out Db4o for an asp.net MVC 2 application idea but there are a few things I'm not quite sure on the best way to proceed. I want my application to use guessable routes rather than Id's for referencing my entities but I also think I need Id's of some sort for update scenarios. so for example I want /country/usa instead of /country/1 I may want to change the key name though (not perhaps on a country but on other entities) so am thinking I need an Id to use as the reference

问题 I have a set of objects in db4o format in a .dat file. The objects in that file are OldNamespace.MyObject, OldAssemblyName. The problem is I've since renamed the namespace and assembly to something more permanent. Short of renaming the assembly and namespace (which is what I'm doing), is there a way of opening the objects into the new assembly/namespace names? Or am I stuck forever with "MyTest3" for the assembly name and namespace?! 回答1: I found the answer faster than I thought I would, in

问题 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 scenario? Server implementation is below. The client connects, queries (read-only), and disconnects per operation, and operations run one immediately after the

问题 I'm intrigued to test new frameworks in the Java world, and decided to create a new project that takes advantage of Maven and db4o. I'm starting to get a hang of Maven, but I have a hard time adding db4o as a dependency to the project. First problem is that db4o doesn't exist in the official Maven repositories. Next up comes the problem that db4o seem to have recently restructured their whole site's URI:s, so I'm getting 'site not found' messages all the time when I try to navigate their site

问题 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? 回答1: We run DB40 .NET version in a large client/server project. Our experiences is that you can potentially get much better performance than typical relational databases. However, you really have to tweak your objects to get this kind of performance. For