JPA 菜鸟教程 5 双向一对多

GitHub

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双向一对多的ddl语句

同单向多对一，单向一对多表的ddl语句一致

Product

package com.jege.jpa.one2many;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;
import javax.persistence.Table;

/**
 * @author JE哥
 * @email 1272434821@qq.com
 * @description:双向:多个商品属于同一个商品类型
 */
@Entity
@Table(name = "t_product")
public class Product {
   
  @Id
  @GeneratedValue
  private Long id;
  private String name;
  // 多对一
  // optional=false表示外键type_id不能为空
  @ManyToOne(optional = true)
  @JoinColumn(name = "type_id")
  private ProductType type;

  public Product() {

  }

  public Product(String name, ProductType type) {
    this.name = name;
    this.type = type;
  }

  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 ProductType getType() {
    return type;
  }

  public void setType(ProductType type) {
    this.type = type;
  }

  @Override
  public String toString(