Hibernate当两个表都有复合主键时,加入两个不相关的表

Question

我正在编写java应用程序,hibernate 5.2但没有HQL

有两张桌子,Transactions和ResponseCode

我希望由Hibernate生成的select语句的逻辑看起来应该如下所示

SELECT t.tranType
      ,t.tranId
      ,t.requestDate
      ,t.rcCode
      ,t.tranAmount
      ,r.description
      ,r.status
  FROM transactions t
  LEFT OUTER JOIN responseCode r
    ON t.rcCode = r.rcCode
   AND (r.lang = 'en')
 WHERE (t.merchant_id =5 )

但是我的代码出了问题,这是我的实现代码段

交易实体

@Entity
@Table(name = "transactions")
public class Transaction implements java.io.Serializable {
    private static final long serialVersionUID = 1L;

        @Column(name = "merchant_id", nullable = true)
        private String merchantID;

        @Column(name = "tran_amount", nullable = true)
        private String tranAmount;

        @Id
        @Column(name = "tran_type", nullable = true)
        private String tranType;

        @Column(name = "auth_request_date", nullable = true)
        @Temporal(TemporalType.TIMESTAMP)
        private Date authRequestDate;

        @Id
        @Column(name = "tran_id", nullable = true)
        private String tranID;

        @OneToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
        @JoinColumn(name="rc")
        private ResponseCode rc;

        // Contructos and getters/setters

ResponseCode实体

@Entity
@Table(name = "response_codes")

public class ResponseCode implements java.io.Serializable {
    private static final long serialVersionUID = 1L;

    @Id
    @Column(name = "response_code")
    private String rcCode;

    @Column(name = "rc_status")
    private String rcStatus;

    @Column(name = "rc_description")
    private String rcDesc;

    @Column(name = "rc_lang")
    private String rcLang;
    // Contructos and getters/setters

实施代码

CriteriaBuilder builder = session.getCriteriaBuilder();
CriteriaQuery<Transaction> criteria = builder.createQuery(Transaction.class);
Root<Transaction> transaction = criteria.from(Transaction.class);
Join<Transaction, ResponseCode> bJoin = transaction.join("rc",JoinType.LEFT);
bJoin.on(builder.equal(bJoin.get("rcLang"), tRequest.getLang()));

Predicate predicate = builder.and(transaction.get("merchantID").in(tRequest.getMerchantList()));
predicate = builder.and(predicate, builder.between(transaction.get("authRequestDate"), dateFrom, dateTo));
criteria.where(predicate);

Hibernate生成两个select语句,第一个语句获取事务列表,第二个语句获取包含在事务列表中的响应代码详细信息.

例如: 如果有30000个事务,15000个事务有000个响应代码,5000个事务有116个响应代码,10000个事务有400个响应代码,它将运行第二个select语句三次,分别为000,116和400个rcCode.

但问题是该ResponseCode表包含一个响应代码的几种语言

第一个select语句包含对语言的限制,但第二个select语句没有这个限制,并且它不计量在第一个语句中提供哪种语言,事务对象的最终结果包含一些事务en语言rc描述和某些事务ge语言rc说明.

我认为这取决于oracle最后选择的语言描述

Hibernate生成选择我

SELECT t.tran_type
      ,t.tran_id
      ,t.auth_request_date
      ,t.merchant_id
      ,t.rc
      ,t.tran_amount
  FROM transactions t
  LEFT OUTER JOIN response_codes r
    ON t.rc = r.response_code
   AND (r.rc_lang = ?)
 WHERE (t.merchant_id IN (?))
   AND (t.AUTH_REQUEST_DATE BETWEEN ? AND ?)
 ORDER BY t.AUTH_REQUEST_DATE ASC

Hibernate生成了select II

SELECT r.response_code  
      ,r.rc_description 
      ,r.rc_lang        
      ,r.rc_status      
  FROM response_codes r
 WHERE r.response_code = ? 
 //this select statement should have 'AND r.rc_lang = ?'

Ps 如果我OneToMany建立关系,它将获得30000个事务并执行30000个额外查询以获取每个操作的响应代码描述

你知道怎么解决吗？

Answer 1

最后我发现

Criteria API 不支持加入不相关的实体。JPQL 也不支持这一点。然而，Hibernate 从 5.1 开始在 HQL 中支持它。 https://discourse.hibernate.org/t/join-two-table-when-both-has-composite-primary-key/1966

也许有一些解决方法，但在这种情况下，我认为更好的方法是使用 HQL 而不是 Criteria API。

这是HQL实现代码片段（实体类中没有任何改变）

String hql = "FROM Transaction t \r\n" + 
             " LEFT OUTER JOIN FETCH t.rc r \r\n" +
             " WHERE (t.merchantID IN (:merchant_id))\r\n" +
             " AND (t.authRequestDate BETWEEN :from AND :to)\r\n" +
             " AND (r.rcLang = :rcLang or r.rcLang is null)\r\n";

Query query =  session.createQuery(hql,Transaction.class);
query.setParameter("merchant_id", tRequest.getMerchantList());
query.setParameter("rcLang", tRequest.getLang());
query.setParameter("from", dateFrom);
query.setParameter("to", dateTo);

List<Transaction> dbTransaction = query.getResultList();