hibernate注解关联

最新推荐文章于 2022-01-01 10:00:00 发布

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最新推荐文章于 2022-01-01 10:00:00 发布

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文章标签： hibernate onetoone onetomany manytomany

本文链接：https://blog.youkuaiyun.com/qq_33565984/article/details/78253661

OntToOne

<!--Person类-->
@Entity
@Table(name="person")
public class Person {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long id;
    private String name;
    /*
     * mappedBy
     * 由另一方来维护外键
     * */
    @OneToOne(targetEntity=Card.class,mappedBy="person")
    private Card card;

《！--Card类--》
@Entity
@Table(name="card")
public class Card {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long cid;
    private String cname;
    @ManyToOne(targetEntity=Person.class)
    @JoinColumn(name="id",unique=true)
    @Cascade(value={CascadeType.SAVE_UPDATE})
    private Person person;

OneToMany

<!--user类-->
@Entity
@Table(name="tb_user")
public class User {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long uid;
    private String name;
    @OneToMany(targetEntity=Order2.class)
    @JoinColumn(name="uid")
    @Cascade(CascadeType.SAVE_UPDATE)
    private Set<Order2> set = new HashSet<>();

<!--Order类-->
@Entity
@Table(name="tb_order")
public class Order2 {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long Oid;
    private String name;
    @ManyToOne(targetEntity=User.class)
    @JoinColumn(name="uid")
    @Cascade(CascadeType.SAVE_UPDATE)
    private User user;

ManyToMany

<!--Student类-->
@Entity
@Table(name="tb_student")
public class Student {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long sid;
    private String name;
    @ManyToMany(targetEntity=Teacher.class)
    @JoinTable(name="tb_tea_stu",joinColumns={@JoinColumn(name="sid")},inverseJoinColumns={@JoinColumn(name="tid")})
    @Cascade(CascadeType.SAVE_UPDATE)
    private Set<Teacher> Teacherset = new HashSet<>();

<!--Teacher类-->
    @Entity
@Table(name="tb_treacher")
public class Teacher {
    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private long tid;
    private String name;
    @ManyToMany(targetEntity=Student.class)
    @JoinTable(name="tb_tea_stu",joinColumns={@JoinColumn(name="tid")},inverseJoinColumns={@JoinColumn(name="sid")})
    @Cascade(CascadeType.SAVE_UPDATE)
    private Set<Student> studentset = new HashSet<>();