JPA联合主键并做从表外键

最新推荐文章于 2025-11-17 15:09:08 发布

原创最新推荐文章于 2025-11-17 15:09:08 发布 · 置顶 · 6.4k 阅读

6 ·

CC 4.0 BY-SA版权

java 同时被 2 个专栏收录

7 篇文章

订阅专栏

JPA

4 篇文章

订阅专栏

本文探讨了如何在Java持久化API（JPA）中设置联合主键，并将其作为从表的外键进行管理。通过实例解析了JPA配置联合主键和外键的步骤，详细介绍了相关数据库关系的建立和操作。

1. 数据库关系

@Embeddable
public class BasicOrderPK implements Serializable {
        ...
        // 联合主键的两个字段单独生成一个可嵌入的对象
	@Column(name="order_id")
	private int orderId;

	@Column(name="goods_code")
	private int goodsCode;
        ...
}


@Entity
@Table(name="basic_order")
@NamedQuery(name="BasicOrder.findAll", query="SELECT b FROM BasicOrder b")
public class BasicOrder implements Serializable {
	private static final long serialVersionUID = 1L;

	@EmbeddedId
        // 注入主键对象
	private BasicOrderPK id;

	//bi-directional many-to-one association to BasicUser
	@ManyToOne(fetch=FetchType.LAZY)
	@JoinColumn(name="user_name")
	private BasicUser basicUser;

	//bi-directional many-to-one association to OrderDetail
	@OneToMany(mappedBy="basicOrder")
	private List<OrderDetail> orderDetails;
}


@Entity
@Table(name="order_detail")
@NamedQuery(name="OrderDetail.findAll", query="SELECT o FROM OrderDetail o")
public class OrderDetail implements Serializable {
        .....
	//bi-directional many-to-one association to BasicOrder
	@ManyToOne(fetch=FetchType.LAZY)
	@JoinColumns({
                // 分别匹配主表联合主键的两个字段
		@JoinColumn(name="order_id", referencedColumnName="order_id"),
		@JoinColumn(name="goods_code", referencedColumnName="goods_code")
		})
	private BasicOrder basicOrder;
....
}