HQL问题

Question

大家好，我有这些课程

@Entity
@Table(name = "login", uniqueConstraints={@UniqueConstraint(columnNames={"username_fk"})})
public class Login implements Serializable {

    @Id
    @Column(name = "id")
    @GeneratedValue
    private int id;
    @Column(name = "password", length = 64)
    private String password;
    @Column(name = "roles", length = 32)
    private String roles;
    @OneToOne(fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    @OnDelete(action=OnDeleteAction.CASCADE)
    @Cascade(org.hibernate.annotations.CascadeType.DELETE_ORPHAN)
    @JoinColumn(name = "username_fk", nullable=false)
    private Branch branch;
    //some getter and sette

和

@Entity
@Table(name = "branch", uniqueConstraints = {@UniqueConstraint(columnNames = {"bname", "branch_fk"})})
public class Branch implements Serializable {

    @Id
    @GeneratedValue
    private int id;
    @Column(name = "username", length = 64, nullable=false)
    private String userName;
    @Column(name = "bname", length = 64)
    private String branchName;
    @Column(name = "officername", length = 64)
    private String officerName;
    @Column(name = "studcount")
    private int studCount;
    @Column(name = "blevel", columnDefinition="int default 0")
    private int level;
    @Column(name = "officeremail", length = 64)
    private String officerEmail;   
    @Column(name = "confirmed", columnDefinition = "tinyint default 0")
    private int confirmed;

    @OneToOne(mappedBy = "branch", fetch = FetchType.LAZY, cascade = CascadeType.ALL)
    @OnDelete(action=OnDeleteAction.CASCADE)
    @Cascade(org.hibernate.annotations.CascadeType.DELETE_ORPHAN)
    private Login login;

当我使用这个查询时：

executeQuery("select l from Login as l inner join l.branch as b where l.branch.bname = ?", username)

或者这个：

executeQuery("select b.login from Branch b where b.username = ?", username)

我收到了这个错误：

org.hibernate.QueryException: could not resolve property: bname of: Data.Entity.Branch

但是当使用这个代码时：

executeQuery("select b.login from Branch b where b.id = ?", username)
it's return correct result

我的意思是这种类型的 HQL 只适用于主键？还是我的映射有问题？ 有什么方法可以使用其他字段（主键除外）形成可连接表？

Answer 1

Hibernate 期望您使用属性名称而不是数据库列名称，即 branchName insted 的 bname 和 userName 而不是 username。

因此，如果您将查询更改为

executeQuery("select l from Login as l inner join l.branch as b " +
     "where l.branch.branchName  = ?",
     username);

和

executeQuery("select b.login from Branch b where b.userName = ?", username);

，一切都应该按预期工作。