Question

我确信这是一个简单的问题，但是在尝试使其工作时遇到了问题。简而言之，我在Web应用程序中使用了搜索功能（使用JPA 2.1，Java 1.7.0 JDK，Primefaces 4.0，Oracle 10g db，JBoss EAP 6.2，NetBeans 8.0 IDE），它应该搜索数据库中的2个表（ “父母”和“孩子”）。更具体地说，我想从子表中获取2个值，并且与父表中的数据一起使用结果填充表单。

实体：

“父”实体

`@Entity
@Table(name = "FOREIGN_PARTY")
@NamedQueries({@NamedQuery(name = "ForeignParty.findbyPolicy1Num", query = "SELECT f FROM ForeignParty f JOIN f.policyPaymentCollection pp WHERE pp.policy1Num = :policy1Num")})

@OneToMany(cascade = CascadeType.ALL, mappedBy = "foreignPartyId")
    private Collection<PolicyPayment> policyPaymentCollection;

// getter and setter for Collection field`

“儿童”实体

@Entity
@Table(name = "POLICY_PAYMENT")

@JoinColumn(name = "FOREIGN_PARTY_ID", referencedColumnName = "FOREIGN_PARTY_ID")
@ManyToOne
private ForeignParty foreignPartyId;

// getter and setter for foreignPartyId field

根据用户在primefaces搜索表单上输入的条件，调用以下逻辑：

public void findSearchCriteriaItems() {
    if (!selected.getSourceClientId().equals("") && !selected.getSourceSystem().equals("")
            && !this.policyPaymentController.getSelected().getPolicy1Num().equals("")) {
        listSearchItemsEJB = ejbFacade.findRecordsBySourceSystemClientIdPolicyNum(selected.getSourceClientId(), 
            selected.getSourceSystem(), this.policyPaymentController.getSelected().getPolicy1Num());
    } else if (!selected.getSourceClientId().equals("") && this.policyPaymentController.getSelected().getPolicy1Num().equals("")
            && selected.getSourceSystem().equals("")) {
        listSearchItemsEJB = ejbFacade.findRecordsBySourceClientId(selected.getSourceClientId());
    } else if (selected.getSourceClientId().equals("")  && this.policyPaymentController.getSelected().getPolicy1Num().equals("")
            && !selected.getSourceSystem().equals("")) {
        listSearchItemsEJB = ejbFacade.findRecordsBySourceSystem(selected.getSourceSystem());
    } else if (selected.getSourceSystem().equals("") && selected.getSourceClientId().equals("") 
            && !this.policyPaymentController.getSelected().getPolicy1Num().equals("")) {
        listSearchItemsEJB = ejbFacade.findRecordsByPolicyNum(this.policyPaymentController.getSelected().getPolicy1Num());
    } else {
        listSearchItemsEJB = null;
    }
    for (int i = 0; i < listSearchItemsEJB.size(); i++) {
        ForeignParty searchRecords = listSearchItemsEJB.get(i);
        items.add((ForeignParty) searchRecords);
    }
}

查询db：

的查询

@PersistenceContext(unitName = "FatcaPU")
    private EntityManager em;

    private Query query;

    @Override
    protected EntityManager getEntityManager() {
        return em;
    }

public List<ForeignParty> findRecordsByPolicyNum(String policyNum) {
        query = em.createNamedQuery("ForeignParty.findbyPolicy1Num");
        query.setParameter("policy1Num", policyNum);
        List<ForeignParty> searchCriteriaList  = (List<ForeignParty>) query.getResultList();
        return searchCriteriaList;
    }

问题是并非所有数据都是从“子”表返回的，因此不会在表单中填充。所以，基本上，“子”表中只有2个值需要检索并放入表单中。如果上面的代码看起来令人困惑，我很抱歉。我离开了很多，因为这些课程相当大。任何帮助将不胜感激，如果需要更多信息，我将很乐意提供。谢谢！

从＆＃34; child＆＃34;中检索特定值表（JPQL）

0 个答案: