Hibernate映射3個實體一個連接表

Question

我有3個表skill_checklist，skill_group，skill_master和映射表skill_checklist_group_master

該協會是爲

checklist <-- many to many --> Group 
Group <-- many to many --> skills 

有人能告訴我如何管理這3 hibernate中的表關聯與註釋？

下面是我的表結構

CREATE TABLE public.skill_checklist 
(
    id bigint NOT NULL DEFAULT nextval('skill_checklist_id_seq'::regclass), 
    name character varying(256) NOT NULL, 
    description character varying(500) NOT NULL, 
    CONSTRAINT "PK_SKILL_CHECKLIST_ID" PRIMARY KEY (id) 
) 

CREATE TABLE public.skill_group 
(
    id bigint NOT NULL DEFAULT nextval('skill_group_id_seq'::regclass), 
    name character varying(256) NOT NULL, 
    description character varying(500) NOT NULL, 
    CONSTRAINT "PK_SKILL_GROUP_ID" PRIMARY KEY (id) 
) 

CREATE TABLE public.skill_master 
(
    id bigint NOT NULL DEFAULT nextval('skill_master_id_seq'::regclass), 
    name character varying(256) NOT NULL, 
    description character varying(500) NOT NULL, 
    CONSTRAINT "PK_SKILL_MASTER_ID" PRIMARY KEY (id) 
) 

CREATE TABLE public.skill_checklist_group_master 
(
    checklist_id bigint NOT NULL, 
    group_id bigint NOT NULL, 
    skill_id bigint NOT NULL, 
    group_order bigint NOT NULL, 
    skill_order bigint NOT NULL, 
    CONSTRAINT "FK_MAP_CHECKLIST_CHECKLIST_ID" FOREIGN KEY (checklist_id) 
     REFERENCES public.skill_checklist (id) MATCH SIMPLE 
     ON UPDATE NO ACTION ON DELETE NO ACTION, 
    CONSTRAINT "FK_MAP_GROUP_GROUP_ID" FOREIGN KEY (group_id) 
     REFERENCES public.skill_group (id) MATCH SIMPLE 
     ON UPDATE NO ACTION ON DELETE NO ACTION, 
    CONSTRAINT "FK_MAP_SKILL_SKILL_ID" FOREIGN KEY (skill_id) 
     REFERENCES public.skill_master (id) MATCH SIMPLE 
     ON UPDATE NO ACTION ON DELETE NO ACTION 
) 

我沒有用Hibernate經驗，所以編碼的例子一定會幫助我在這裏。使用最新版本的hibernate。

Answer 1

使用Hibernate，您可以定義實體中的每個數據表。每個實體都有自己的專欄註釋。

下面是一個例子..

import javax.persistence.*; 

@Entity 
@Table(name = "EMPLOYEE") 
public class Employee { 
    @Id @GeneratedValue 
    @Column(name = "id") 
    private int id; 

    @Column(name = "first_name") 
    private String firstName; 

    @Column(name = "last_name") 
    private String lastName; 

    @Column(name = "salary") 
    private int salary; 

    public Employee() {} 
    public int getId() { 
     return id; 
    } 
    public void setId(int id) { 
     this.id = id; 
    } 
    public String getFirstName() { 
     return firstName; 
    } 
    public void setFirstName(String first_name) { 
     this.firstName = first_name; 
    } 
    public String getLastName() { 
     return lastName; 
    } 
    public void setLastName(String last_name) { 
     this.lastName = last_name; 
    } 
    public int getSalary() { 
     return salary; 
    } 
    public void setSalary(int salary) { 
     this.salary = salary; 
    } 
} 

怎麼可以看到每個實體都有自己擁有的註釋和他擁有的GET方法和他的專欄設置數據..

如果你使用Eclipse或netbeans，他們有他自己的插件，用於在實體中自動轉換數據表..