Hibernate Ⅳ 映射關係

一對一單向外鍵關聯

Annotation: @OneToOne
因爲Hibernate自動生成的名稱不能改，所以最好是自己把表建好然後設置好對應的映射關係
使用@JoinColumn指定對應映射的數據庫中的列名

一對一雙向外鍵關聯

Annotation: @OnetoOne(mappedBy)
不是真正的去建立一個雙向的外鍵，因爲這樣是冗餘字段
所以先使用一個OneToOne，然後在被關聯的添加這個註解，表明是一個映射關係

@Entity
public class Husband {
    private int id;
    private String name;
    private Wife wife;
    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }

public String getName() {
    return name;
}
@OneToOne
@JoinColumn(name="wifeId")
public Wife getWife() {
    return wife;
}
public void setId(int id) {
    this.id = id;
}
public void setName(String name) {
    this.name = name;
}
public void setWife(Wife wife) {
    this.wife = wife;
}

}




@Entity
public class Wife {
    private int id;
    private String name;
    private Husband husband;
    @OneToOne(mappedBy="wife")
    public Husband getHusband() {
        return husband;
    }
    public void setHusband(Husband husband) {
        this.husband = husband;
    }
    @Id
    @GeneratedValue
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

}