Hibernate 级联问题

Question

现在有个查询问题，请教哈大家。希望能得到帮助：

假如A表(id,name)

   B表(id,name,fk_c,fk_a)

   C表(id,name)

A表中有B对象，B表中有C对象，现在要根据C的条件来查询A的集合。

请问这个实体该如何映射啊，噢是hibernate annoteration 注释的。

public class A{

     private String id;

     private String name;

     @OneToMany(mappedBy="eachGroup",fetch=FetchType.EAGER,cascade={CascadeType.MERGE,CascadeType.PERSIST})

     private List b;

}

public class B{

     private String id;

     private String name;

     @ManyToOne

     @JoinColumn(name = "fk_a")

     private A a;

     @ManyToOne

     @JoinColumn(name = "fk_c")

     private C c;

}

SQL:"如何根据B对象中的C条件把集合A查询出来"？

Answer 1

annoteration这样配置就可以了：

[code="java"]@Entity
@Table
public class A{
private String id;
private String name;
@OneToMany(targetEntity = A.class, mappedBy = "a")
private List b;
}
@Entity
@Table
public class B{
private String id;
private String name;
@ManyToOne
@JoinColumn(name = "fk_a")
private A a;
@ManyToOne
@JoinColumn(name = "fk_c")
private C c;
}
@Entity
@Table
public class C{
private String id;
@OneToMany(targetEntity = C.class, mappedBy = "c")
private List b;
}[/code]