过滤器不适用于一对多关系的 JPQL 查询

Question

>我创建了以下类，即教师和学生。

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：教师

@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：类型

@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，学生是孩子班。我希望所有教师和他们的学生的过滤器类型id为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 在实体管理器中创建查询：异常说明：问题 编译查询。状态字段路径"teacher.std.typeid"不能 解析为有效类型。

Answer 1

您的查询是错误的。你有Teacher有std（Student），std有类型（Type）和类型有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