20.hibernate继承映射single_table

最新推荐文章于 2025-07-28 23:27:29 发布

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#hibernate #继承映射 #singletable

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本文深入探讨了使用Hibernate框架时，如何通过单一表结构实现多态继承，具体展示了如何定义和使用Person基类以及其子类Teacher和Student。详细解释了在数据库设计中利用单一表来存储不同类型的对象实例，并通过discriminator列区分它们的类型。通过实例代码，清晰地展示了在Java类结构中实现多态性的方法。

单个表:
person表结构如下:
[img]http://dl.iteye.com/upload/attachment/592688/bbd7daeb-be95-3dbc-8982-dfa969f83bfb.jpg[/img]


package com.bjsxt.hibernate;

import javax.persistence.DiscriminatorColumn;
import javax.persistence.DiscriminatorType;
import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Inheritance;
import javax.persistence.InheritanceType;

@Entity
@Inheritance(strategy=InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name="discriminator", discriminatorType=DiscriminatorType.STRING)
@DiscriminatorValue("person")
public class Person {
	private int id;
	private String name;

	@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;
	}

}


package com.bjsxt.hibernate;

import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;

@Entity
@DiscriminatorValue("teacher")
public class Teacher extends Person {
	private String title;

	public String getTitle() {
		return title;
	}

	public void setTitle(String title) {
		this.title = title;
	}


}


package com.bjsxt.hibernate;

import javax.persistence.DiscriminatorValue;
import javax.persistence.Entity;

@Entity
@DiscriminatorValue("student")
public class Student extends Person {

	private int score;

	public int getScore() {
		return score;
	}

	public void setScore(int score) {
		this.score = score;
	}

}