小编Obj*_*tDB的帖子

在这个基准测试中,ObjectDB是最快的数据库:http: //www.jpab.org/All/All/All.html

但我看不到ObjectDB的任何其他基准测试结果.是否有人使用ObjectDB？生产准备好了吗？有什么经历？

我是JPA/JDO和整个objectdb世界的新手.

我有一个带有一组字符串的实体,看起来有点像:

@Entity
public class Foo{

    @Id
    @GeneratedValue(strategy=GenerationType.IDENTITY)
    private Key id;

    private Set<String> bars;

    public void setBars(Set<String> newBars){
        if(this.bars == null)
            this.bars = new HashSet<String>;
        this.bars = newBars;
    }

    public Set<String> getBars(){
        return this.bars;
    }

    public void addBar(String bar){
        if(this.bars == null)
            this.bars = new HashSet<String>;
        this.bars.add(bar);
    }

}

现在,在代码的另一部分,我正在尝试做这样的事情:

EntityManager em = EMF.get().createEntityManager();
Foo myFoo = em.find(Foo.class, fooKey);
em.getTransaction().begin();
myFoo.addBar(newBar);
em.merge(myFoo);
em.getTransaction().commit();

当然,当newBar是String时.

但是,我得到的是:

javax.jdo.JDODetachedFieldAccessException: You have just attempted to access field      "bars" yet this field was not detached …