java - Hibernate 连接表

Question

我有两个表:

人

ID | NAME | EMAIL_ID (foreign key of Email.ID)

电子邮件

ID | EMAIL_ADDRESS

我需要将数据拉回以下实体，但我不确定如何使用注释将 PERSON.EMAIL_ID 与 EMAIL.ID 连接

@Entity
@Table(name = "PERSON")
public class PersonEntity {
    @Column(name = "ID")
    private String id;

    @Column(name = "NAME")
    private String name;

    // How do I do a one to one join here?
    private String emailAddress;
}

如何正确使用注释，以便 emailAddress 字段映射到 EMAIL.EMAIL_ADDRESS 列？

Answer 1

您的 Person 实体应与 Email 实体连接，而不是直接与 emailAddress 属性连接。

@Entity
@Table(name = "PERSON")
public class PersonEntity {
    @Column(name = "ID")
    private String id;

    @Column(name = "NAME")
    private String name;

    @OneToOne(fetch = FetchType.LAZY, mappedBy = "person", cascade = CascadeType.ALL)
    private Email email;
}

但是有一个仅用于电子邮件的实体很奇怪。您只确保电子邮件是唯一的吗？在这种情况下，Person 实体可以有一个带有 @Column(unique = true) 的 emailAddress。

@Entity
@Table(name = "PERSON")
public class PersonEntity {
    @Column(name = "ID")
    private String id;

    @Column(name = "NAME")
    private String name;

    @Column(unique = true)
    private String emailAddress;
}