Mapped Superclass - 매핑 정보 상속 / 상속관계 매핑

BaseEntity 클래스를 만들어보자.

 

추상클래스로 쓰자.

@MappedSuperclass
public abstract class BaseEntity {

package hellojpa;

import javax.persistence.MappedSuperclass;
import java.time.LocalDateTime;

@MappedSuperclass
public class BaseEntity {

    private String createdBy;
    private LocalDateTime createdDate;
    private String lastModifiedBy;
    private LocalDateTime lastModifiedDate;

    public String getCreatedBy() {
        return createdBy;
    }

    public void setCreatedBy(String createdBy) {
        this.createdBy = createdBy;
    }

    public LocalDateTime getCreatedDate() {
        return createdDate;
    }

    public void setCreatedDate(LocalDateTime createdDate) {
        this.createdDate = createdDate;
    }

    public String getLastModifiedBy() {
        return lastModifiedBy;
    }

    public void setLastModifiedBy(String lastModifiedBy) {
        this.lastModifiedBy = lastModifiedBy;
    }

    public LocalDateTime getLastModifiedDate() {
        return lastModifiedDate;
    }

    public void setLastModifiedDate(LocalDateTime lastModifiedDate) {
        this.lastModifiedDate = lastModifiedDate;
    }
}

 

 

Member 클래스에서

public class Member extends BaseEntity {

 

Team 클래스에서

public class Team extends BaseEntity {

 

 

Member와 Team에도 이렇게 createdate,  createdBy가 생겼다.

try {

            Member member = new Member();
            member.setUsername("user1");
            member.setCreatedBy("kim");
            member.setCreatedDate(LocalDateTime.now());

            em.persist(member);

            em.flush();
            em.clear();

            tx.commit();
        } catch (Exception e) {
            tx.rollback();
        } finally {
            em.close();
        }
        emf.close();

Hibernate: 
    
    create table Member (
       MEMBER_ID bigint not null,
        createdBy varchar(255),
        createdDate timestamp,
        lastModifiedBy varchar(255),
        lastModifiedDate timestamp,
        USERNAME varchar(255),
        LOCKER_ID bigint,
        TEAM_ID bigint,
        primary key (MEMBER_ID)
    )
    
    
    create table Team (
       TEAM_ID bigint not null,
        createdBy varchar(255),
        createdDate timestamp,
        lastModifiedBy varchar(255),
        lastModifiedDate timestamp,
        name varchar(255),
        primary key (TEAM_ID)
    )

 

 

 

 

 

@Column이렇게 넣어주면 MEMBER 테이블 / TEAM 테이블 각각 INSERT_MEMBER가 생긴다.

@MappedSuperclass
public class BaseEntity {

    @Column(name = "INSERT_MEMBER")
    private String createdBy;
    private LocalDateTime createdDate;
    @Column(name = "UPDATE_MEMBER")
    private String lastModifiedBy;
    private LocalDateTime lastModifiedDate;

create table Member (
       MEMBER_ID bigint not null,
        INSERT_MEMBER varchar(255),
        createdDate timestamp,
        UPDATE_MEMBER varchar(255),
        lastModifiedDate timestamp,
        USERNAME varchar(255),
        LOCKER_ID bigint,
        TEAM_ID bigint,
        primary key (MEMBER_ID)
    )

create table Team (
       TEAM_ID bigint not null,
        INSERT_MEMBER varchar(255),
        createdDate timestamp,
        UPDATE_MEMBER varchar(255),
        lastModifiedDate timestamp,
        name varchar(255),
        primary key (TEAM_ID)
    )

 

@MappedSuperclass

• 상속관계 매핑X

 

• 엔티티X, 테이블과 매핑X

 

• 부모 클래스를 상속 받는 자식 클래스에 매핑 정보만 제공

 

• 조회, 검색 불가(em.find(BaseEntity) 불가)

 

• 직접 생성해서 사용할 일이 없으므로 추상 클래스 권장

 

• 테이블과 관계 없다. 단순히 엔티티가 공통으로 사용하는 매핑 정보를 모으는 역할

 

• 주로 등록일, 수정일, 등록자, 수정자 같은 전체 엔티티에서 공통으로 적용하는 정보 모을 때 사용

 

• @Entity 클래스는 엔티티나 @MappedSuperclass로 지정한 클래스만 상속 가능

 

 

 

 

상속관계 매핑

• 상품의 종류 음반, 도서 영화가 있고 더 확장 가능(상속관계 매핑을 쓰고)
• 모든 데이터 등록일과 수정일이 필수(mappedSuperclass를 쓴다.)

 

 

Album, Book, Movie를 각각 세팅

 

Album

package jpabook.jpashop.domain;

import javax.persistence.Entity;

@Entity
public class Album extends Item{
    private String artist;
    private String etc;

    public String getArtist() {
        return artist;
    }

    public void setArtist(String artist) {
        this.artist = artist;
    }

    public String getEtc() {
        return etc;
    }

    public void setEtc(String etc) {
        this.etc = etc;
    }
}

 

Book

package jpabook.jpashop.domain;

import javax.persistence.Entity;

@Entity
public class Book extends Item{

    private String author;
    private String isbn;

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getIsbn() {
        return isbn;
    }

    public void setIsbn(String isbn) {
        this.isbn = isbn;
    }
}

 

 

Movie

package jpabook.jpashop.domain;

import javax.persistence.Entity;

@Entity
public class Movie extends Item {

    private String director;
    private String actor;

    public String getDirector() {
        return director;
    }

    public void setDirector(String director) {
        this.director = director;
    }

    public String getActor() {
        return actor;
    }

    public void setActor(String actor) {
        this.actor = actor;
    }
}

 

 

 

 

 

 

 

ItemClass를 아래와 같이 @Inheritance, DiscriminatorColumn으로 설정

package jpabook.jpashop.domain;


import javax.persistence.*;
import java.util.ArrayList;
import java.util.List;

@Entity
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn
public class Item {

    @Id @GeneratedValue
    @Column(name = "ITEM_ID")
    private Long id;

    private String name;
    private int price;
    private int stockQuantity;

    @ManyToMany(mappedBy = "items")
    private List<Category> categories = new ArrayList<>();

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getPrice() {
        return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public int getStockQuantity() {
        return stockQuantity;
    }

    public void setStockQuantity(int stockQuantity) {
        this.stockQuantity = stockQuantity;
    }
}

create table Item (
       DTYPE varchar(31) not null,
        ITEM_ID bigint not null,
        name varchar(255),
        price integer not null,
        stockQuantity integer not null,
        actor varchar(255),
        director varchar(255),
        author varchar(255),
        isbn varchar(255),
        artist varchar(255),
        etc varchar(255),
        primary key (ITEM_ID)
    )

 

 

 

JpaMain에서 저장을 해주자.

package jpabook.jpashop;

import jpabook.jpashop.domain.Book;
import jpabook.jpashop.domain.Order;
import jpabook.jpashop.domain.OrderItem;

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityTransaction;
import javax.persistence.Persistence;

public class JpaMain {

    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("hello");

        EntityManager em = emf.createEntityManager();

        EntityTransaction tx = em.getTransaction();
        tx.begin();

        try {

            Book book = new Book();
            book.setName("jpaBIGIN");
            book.setAuthor("Jay");

            em.persist(book);

            tx.commit();
        } catch (Exception e) {
            tx.rollback();
        } finally {
            em.close();
        }

        emf.close();
    }
}

Hibernate: 
    call next value for hibernate_sequence
Hibernate: 
    /* insert jpabook.jpashop.domain.Book
        */ insert 
        into
            Item
            (name, price, stockQuantity, author, isbn, DTYPE, ITEM_ID) 
        values
            (?, ?, ?, ?, ?, 'Book', ?)

 

h2 db를 보니 item table에 내용이 생성이 안된다. 일단 보류하고 해결해보자.

 

 

 

 

 

 

 

 

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