db4o

I am developing an App in which now i have to create database for more better user experience. Then i came to know about DB4o which is many times faster tool for creating database than other like SQLite, MySql etc, but the problem is i am not able to find any single example that explains about DB4o and how to create database using Db4o. If anybody has used it, please post an example or send me link. To store the object in database use db().store(exercise); To retrieve All records from database, use db().query(Object); To retrieve particular record from database, use db().queryByExample(Object)

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? See: http://developer.db4o.com/Projects/html/projectspaces/gaabormarkt.html A particular search engine used to be powered by db4o (I say "used to" because I haven't talked to the author about this since a long

I'm looking for information about DB4O object database. I know it has client/server mode, but I have no idea how scalable it is. I'm a big lover of object db idea, but still couldn't find an appropriate OODB to use in any of my projects. So my questions are: I'm interested if anyone deployed DB4O in a multi client environment and how does it perform compared to RDBMS? Is any web app to date powered by DB4O? Can I use DB4O as a replacement for SQL Server (SQL Express at least)? How many concurrent client can DB4O support in practice? Does performance degrades when DB size increases? Thanks P.S.

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 database, so I simply configured the database to use UUID's. Now the problem has become, how can I get to

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. I found somewhere a potential Maven repository that should be at https://source.db4o.com/maven but I

下载和安装db4o db4o 所有最新的版本都可以直接在官方网站上下载，进入 db4o 的下载页面，我们可以看到最新的 for Java 稳定版本，包括 JAR、源代码、入门文档、API 等内容的完整的打包文件只有 6 MB，db4o 还有一个对象数据库管理工具 ObjectManager，目前版本是 1.8。 接着在 Eclipse 中新建 Java 项目，把 db4o 对象数据库引擎包 db4o-8.0.249.16098-all-java5.jar 导入进项目。由于 db4o 支持多种版本的 JDK，除了 for JDK 5.0 的 db4o-8.0.249.16098-all-java5.jar 外，还有 for JDK 1.1、1.2-1.4 的 JAR 包，以适应多种环境。与 Hibernate、iBATIS SQL Maps 相比，db4o 更加自然，无需过多地引用第三方支持库。 db4o的包结构 db4o 怎样进行对象持久化呢？通过浏览目录可以发现，与传统的 RDBMS 一样，db4o 也有自己的数据库文件, 在 db4o 中数据库文件的后缀名是“*.yap”。让我们先来了解一下 db4o 对象数据库引擎的主要包结构： com.db4o com.db4o 包含了使用 db4o 时最经常用到的功能。两个最重要的接口是 com.db4o.Db4o 和 com.db4o

前言 在开源面向对象数据库 db4o 之旅 系列文章的第 1 部分： 初识 db4o 中，作者介绍了 db4o 的历史和现状，应用领域，以及和 ORM 等的比较； 在第 2 部分： db4o 查询方式 中, 作者介绍了 db4o 的三种不同的查询方式：QBE、SODA 以及 Native Queries，并分别通过这三种不同的途径实现了两个关联对象的查询。 前面我们已经介绍了如何在 db4o 中查询以及添加对象，在本文中我们将会向您介绍在 db4o 中如何对对象进行更新以及删除操作。 更新数据 场景一 我们来设想这样的场景：一位名叫“张三”的人买了车，并上好了牌照（如本系列第二部分之代码），而他基本信息的地址并不详细，只写了“成都市”，在一次主管部门检查此人信息的时候，发现了这个问题，并立即着手修改。 在 db4o 中，我们这样来实现对这个用户信息的修改（ 清单1 ）： 清单1. 修改地址 package com; import bo.People; import com.db4o.Db4o; import com.db4o.ObjectContainer; import com.db4o.ObjectSet; import com.db4o.query.Predicate; public class DB4OTest { public static void main (

前言 业界对持久存储领域的追求从未停止过，为了更方便、更容易地用对象表达我们的思维，开源领域和商业领域都涌现了许多新技术， ORM 的出现恰恰说明了这点。最近一年，业界也在反思，到底 ORM 给我们带来的是便利还是麻烦。矛头指向大名鼎鼎的 Hibernate ，纷纷议论其性能问题，大家似乎要达成这样的共识：“在业务逻辑复杂的地方用 SP ，而一般的 CRUD 还是 Hibernate ”，就连全球知名的 BearingPoint 也有类似看法。下面一个简单的例子，说明了传统 ORM 工具的弊端。让我们考虑一个简单的 Student 对象如 清单1 ： 清单1. Student 类 public class Student { private String name; private int age; public String getName(){ return name; } public int getAge(){ return age; } } 考虑下面这个场景:找到“年龄小于 20 岁的所有学生”？ 使用 ORL 实现如 清单2 ： 清单2. ORL 实现 String oql = "select * from student in AllStudents where student.age <20"; OQLQuery query = new OQLQuery(oql);