EclipSelink左向外连接动态查询格式错误

Question

有两个实体Person和Address。人与地址之间存在1:M关系。（假定某人有临时和永久地址）。

Person类的关键属性是：

< li>personId(pk) < li >性别

地址类的主要属性是:

1. 地址id（pk）
2. 人（fk）
3. 性别

以下是Person和Address类的描述符代码片段:

public RelationalDescriptor buildPersonDescriptor() {
RelationalDescriptor descriptor = new RelationalDescriptor();
descriptor.setJavaClass(Person.class);
descriptor.addTableName("PERSON");
descriptor.addPrimaryKeyFieldName("PERSON.PID");

// RelationalDescriptor properties.
descriptor.useSoftCacheWeakIdentityMap();
descriptor.setIdentityMapSize(100);
descriptor.useRemoteSoftCacheWeakIdentityMap();
descriptor.setRemoteIdentityMapSize(100);
descriptor.setSequenceNumberFieldName("PERSON.PID");
descriptor.setSequenceNumberName("PERSON_SEQ");
descriptor.setAlias("person");

// Query manager.
descriptor.getDescriptorQueryManager().checkCacheForDoesExist();
descriptor.getDescriptorQueryManager().setAdditionalJoinExpression(new ExpressionBuilder().get("gender").equal('N'));


// Query manager.

// Mappings.

DirectToFieldMapping pIDMapping = new DirectToFieldMapping();
pIDMapping.setAttributeName("personId");
pIDMapping.setFieldName("PERSON.PID");
descriptor.addMapping(pIDMapping);

DirectToFieldMapping genderMapping = new DirectToFieldMapping();
genderMapping.setAttributeName("gender");
genderMapping.setFieldName("PERSON.GENDER");
descriptor.addMapping(genderMapping);

OneToManyMapping addressMapping = new OneToManyMapping();
addressMapping.setAttributeName("address");
addressMapping.setReferenceClass(Address.class);
addressMapping.useTransparentCollection();
addressMapping.useCollectionClass(IndirectList.class);
addressMapping.addTargetForeignKeyFieldName("ADDRESS.PID", "PERSON.PID");
descriptor.addMapping(addressMapping);

return descriptor;
}


public RelationalDescriptor buildAddressDescriptor() {

RelationalDescriptor descriptor = new RelationalDescriptor();
  descriptor.setJavaClass(com.tropics.application.products.domain.costingandpricing.SellingPriceAddOn.class);
  descriptor.addTableName("ADDRESS");
  descriptor.addPrimaryKeyFieldName("ADDRESS.AID");

  // Descriptor properties.
  descriptor.useSoftCacheWeakIdentityMap();
  descriptor.setIdentityMapSize(100);
  descriptor.useRemoteSoftCacheWeakIdentityMap();
  descriptor.setRemoteIdentityMapSize(100);
  descriptor.setSequenceNumberFieldName("ADDRESS.AID");
  descriptor.setSequenceNumberName("ADDRESS_SEQ");
  descriptor.setAlias("address");

  // Query manager.
  descriptor.getDescriptorQueryManager().checkCacheForDoesExist();

  //Mappings
  DirectToFieldMapping genderMapping = new DirectToFieldMapping();
  genderMapping.setAttributeName("gender");
  genderMapping.setFieldName("ADDRESS.GENDER");
  descriptor.addMapping(genderMapping); 

  DirectToFieldMapping personIDMapping = new DirectToFieldMapping();
  personIDMapping.setAttributeName("personId");
  personIDMapping.setFieldName("ADDRESS.PID");
  descriptor.addMapping(personIDMapping);

  DirectToFieldMapping addressIDMapping = new DirectToFieldMapping();
  addressIDMapping.setAttributeName("addressId");
  addressIDMapping.setFieldName("ADDRESS.AID");
  descriptor.addMapping(addressIDMapping);  

}

以下是用于生成动态查询的代码片段：

        ExpressionBuilder expBuilder = new ExpressionBuilder();
        ReportQuery query = new ReportQuery(Person.class, expBuilder);

        //Getting the MVSelling DetailsID and the number of Selling price add ons for each of them
        query.addAttribute("personId", expBuilder.get("personId"));
        query.addAttribute
        ("addressCounter", expBuilder.anyOfAllowingNone("address").get("addressId").count());
        Expression addressExp = expBuilder.anyOfAllowingNone("address");
        expBuilder.leftJoin(addressExp, addressExp.get("gender").equal('M'));
        query.addNonFetchJoin(addressExp);
        query.addGrouping("personId");
        resultCollection = (Vector)clientSessionHolder.eclipselinkClientSession().executeQuery(query);

运行此程序时，根据日志生成的查询：

SELECT t0.PID, COUNT(t1.AID)
FROM PERSON t0 LEFT OUTER JOIN ADDRESS t1
ON (t1.PID = t0.PID)
LEFT OUTER JOIN ADDRESS t2
ON ((t2.PID  = t0.PID)
AND (t2.gender = 'M'))
WHERE (t0.gender = 'M')) GROUP BY t0.PID ;

如何编写表达式在第一个join子句中添加性别条件(db中的char数据类型)并去掉第二个join子句？

预期的查询是:SELECT t0。PID，计数(t1。AID)从人t0在(t1)离开外部连接地址t1。PID = t0。PID和(t2.gender = 'M ')，其中t0.gender = 'M '按t0分组。PID

Answer 1

您有两个单独的联接，因为您正在调用和使用expBuilder。anyOfAllowingNone（“地址”）在表达式中出现两次anyOfAllowingNone告诉EclipseLink在关系上创建一个外部联接，并将其用作从该联接构建的表达式的基础。

试试吧

    Expression addressExp = expBuilder.anyOfAllowingNone("address");
    query.addAttribute("addressCounter", addressExp.get("addressId").count());
    expBuilder.leftJoin(addressExp, addressExp.get("gender").equal('M'));
    query.addNonFetchJoin(addressExp);

重复使用addressExp将导致连接只创建一次，其他路径将基于它而不是新的路径。