java - 连接错误 JPA 和named_queries xml 的预期路径

Question

由于这个错误，我对 JPA 和 Hibernate 感到非常困惑。

这是堆栈异常

2012-08-07 03:55:04,277 ERROR [org.hibernate.hql.PARSER] (HDScanner)  Path expected for join!
2012-08-07 03:55:04,299 ERROR [org.hibernate.impl.SessionFactoryImpl] (HDScanner) Error in named query: getTotalCallReportsFromQuarter
org.hibernate.QueryException: Unable to resolve path [care.quarter], unexpected token [care] [SELECT count(noOfCallReports) FROM com.business.model.base.CareCallReport JOIN Relationships with CareCallReport.clientAccountNo=Relationships.clientAccountNo where UID = :UID and care.quarter = :quarter and care.year = :year]

这是我计划加入的 2 个实体:

CareCallReport.java
@Entity
@Table(name = "CARE_CALLREPORT")
public class ICareCallReport implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @Column(name = "ClientAccountNo", nullable = false, length = 7)
    private String clientAccountNo;

    @Column(name = "NoOfCallReports", nullable = false, length = 11)
    private int noOfCallReports;

    @Column(name = "Quarter", nullable = false, length = 11)
    private int quarter;

    @Column(name = "QtrYear", nullable = false, length = 4)
    private int year;

    ... Getters and Setters

以及另一个实体

ITRelationships.java
@Entity
@Table(name = "IT_RELATIONSHIPS")
public class ITRelationships implements Serializable {

    @Id
    @Column(name = "ClientID",nullable = false, length = 7)
    private String clientID;

    @Column(name = "ClientAccountNo", nullable = false, length = 7)
    private String clientAccountNo;

    @Id
    @Column(name = "UID", nullable = false, length = 6)
    private String UID;

    @Column(name = "Quarter", nullable = false, length = 11)
    private int quarter;

    @Column(name = "QtrYear", nullable = false, length = 4)
    private int year;

    Getters and Setters

我写出来的JQL方法是这样的:

<access>FIELD</access>
<named-query name="getTotalCallReportsFromQuarter">
    <query>
        <![CDATA[
        SELECT count(noOfCallReports)
        FROM CareCallReport JOIN ITRelationships
        with CareCallReport.clientAccountNo = ITRelationships.clientAccountNo
        where UID = :uid
            and care.quarter = :quarter
            and care.year = :year
        ]]> 
    </query>
</named-query>

我做错了什么？这是我第一次接触JPA。

Answer 1

您在查询中使用了别名 (icare)，但没有定义它。此外，仅当实体之间存在关联(OneToOne、OneToMany、ManyToOne 或 ManyToMany)时，才可以进行联接。假设您没有，查询应该是

SELECT count(care.noOfCallReports)
    FROM CareCallReport care, ITRelationships relationship
    where relationship.UID = :uid
        and care.quarter = :quarter
        and care.year = :year
        and care.clientAccountNo = relationship.clientAccountNo

the Hibernate documentation 中详细描述了 HQL 和关联。 。阅读它。