過濾器不能處理一對多關系的JPQL查詢

Question

我創建了以下課程，即老師和學生。

JAVA代碼：學生

@Entity
@Table(name="Student")

public class Student {

    @Id
    @Column(name = "cmp_id")
    private String cmpId;

    @OneToOne(cascade = CascadeType.REFRESH)
    @JoinColumn(name = "teacherid", referencedColumnName = "teacherid")
    private Teacher teacher;

    @OneToOne
    @JoinColumn(name = "typeid", referencedColumnName = "typeid")
    private Type type;
}

JAVA代碼：老師

@Entity
@Table(name="Teacher")
public class Teacher {

    @Id
    @Column(name = "teacherid")
    private String teacherid;

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

    @OneToMany(mappedBy = "Teacher", fetch = FetchType.EAGER, cascade = CascadeType.ALL)
    @OrderBy("cmpSequence ASC")
    private List<Student> std;
}

JAVA代碼：類型

@Entity
@Table(name="Type")
public class Type{

    @Id
    @Column(name = "typeid")
    private Integer typeid;

    @Column(name = "uitype")
    private String uitype;    
}

老師是家長班，學生是小學班。我希望所有老師和他們的學生使用過濾器typeid是1，但它不起作用。

以下是我創建的JPQL查詢：

SELECT teacher FROM Teacher teacher WHERE teacher.std.typeid = 1

它給了我以下錯誤：

java.lang.IllegalArgumentException：在EntityManager中創建查詢時發生異常：異常描述：編譯查詢時出現問題。狀態字段路徑“teacher.std.typeid”無法解析為有效類型。

Answer 1

你的查詢錯了。 你有Teacher有std（ Student ），std有類型（ Type ）和類型有類型ID字段。 所以你的查詢應如下所示：

SELECT teacher FROM Teacher teacher 
JOIN FETCH teacher.std AS s 
INNER JOIN s.type as t 
WHERE t.typeid = 1