过滤器不能处理一对多关系的JPQL查询

Question

我创建了以下课程，即老师和学生。

JAVA代码：学生

@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代码：老师

@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代码：输入

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

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

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

老师是家长班，学生是小学班。我希望所有老师和他们的学生使用过滤器typeid是1，但它不起作用。

以下是我创建的JPQL查询：

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

它给了我以下错误：

  

java.lang.IllegalArgumentException：发生异常时   在EntityManager中创建查询：异常描述：问题   编译查询。状态字段路径＆＃39; teacher.std.typeid＆＃39;不可能是   解析为有效类型。

Answer 1

您的查询错误。你有Teacher std（Student），std有类型（Type），类型有typeid字段。因此，您的查询应如下所示：

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