Question

我正在尝试构建一个复杂的查询。我的实体看起来如下：

@Entity
public class Configuration{

   @Id
   @Column(name="CONF_ID")
   protected Long configurationId;

   @ManyToMany
   @MapKey(name="componentType")
   @JoinTable(name="CONF_COMP",
      joinColumns={@JoinColumn(name="CONF_ID", referencedColumnName="CONF_ID")},
      inverseJoinColumns={@JoinColumn(name="COMP_ID", referencedColumnName="componentId")})
   protected Map<String, Component> components;
}

并且

@Entity
public class Component {

    @Id
    protected long componentId; 
    @ElementCollection
    protected Map<String, String> properties;

    @ManyToMany(mappedBy="components")
    private List<Configuration> configurations;

    @Column(name="COMP_TYPE")
    protected String componentType;
 }

我的问题在于正确查询properties字段。我似乎无法创建一个查询来获取所有配置，其中组件A具有属性Prop1 = 1而组件B具有属性Prop2 = 2。我尝试了以下但没有成功。

Root<Configuration> conf = cq.from(Configuration.class);    
MapJoin<Configuration, String, Component> compJoin = conf.join(Configuration_.components, JoinType.LEFT);
MapJoin<Component, String, String> propJoin = compJoin.join(Component_.properties, JoinType.LEFT); 

    Predicate p1 = cb.and(
                cb.equal(mapJoin.key(), "A"),
                cb.equal(propJoin.key(), "Prop1"), cb.equal(propJoin.value(), "1"));
    Predicate p2 = cb.and(
                cb.equal(mapJoin.key(), "B"),
                cb.equal(propJoin.key(), "Prop2"), cb.equal(propJoin.value(), "2"));

Predicate[] pArray = new Predicate[]{p1, p2};
cq.where(pArray);
cq.select(conf).distinct(true);

编辑：记录器输出的查询如下所示：

SELECT DISTINCT  t2.CONF_ID, t2.DTYPE, t2.TOTALPRICE, t2.NAME
 FROM CONFIGURATION t2 
 LEFT OUTER JOIN (CONF_COMP t3 JOIN COMPONENT t1 ON (t1.COMPONENTID = t3.COMP_ID)) ON (t3.CONF_ID = t2.CONF_ID) LEFT OUTER JOIN Component_PROPERTIES t0 ON (t0.Component_COMPONENTID = t1.COMPONENTID) 
WHERE (((((t1.COMP_TYPE = ?) AND (t0.PROPERTIES_KEY = ?)) AND t0.PROPERTIES LIKE ?) AND (((t1.COMP_TYPE = ?) AND (t0.PROPERTIES_KEY = ?)) AND t0.PROPERTIES LIKE ?)) AND (t2.DTYPE = ?))
bind => [7 parameters bound]

我猜它正在尝试找到一个配置，其中所有条件都适用于SAME组件？如果我只对一个Component应用限制，它会起作用，但是当应用2个或更多时，我得到一个空的结果列表，尽管DB中的条目满足条件。

更新

按照Pimgd的建议，我最终得到了一个如下所示的查询：

SELECT DISTINCT t1.CONF_ID, t1.DTYPE, t1.TOTALPRICE, t1.NAME
FROM CONFIGURATION t1 LEFT OUTER JOIN (CONF_COMP t2 JOIN COMPONENT t0 ON (t0.COMPONENTID = t2.COMP_ID)) ON (t2.CONF_ID = t1.CONF_ID) 
WHERE ((( 
    t0.COMPONENTID IN (SELECT t3.COMPONENTID 
                        FROM COMPONENT t3 LEFT OUTER JOIN Component_PROPERTIES t4 ON (t4.Component_COMPONENTID = t3.COMPONENTID) 
                        WHERE ((t4.PROPERTIES_KEY = Brand) AND (t4.PROPERTIES = Intel)))) 

    AND 
    t0.COMPONENTID IN (SELECT t6.COMPONENTID 
                        FROM COMPONENT t6 LEFT OUTER JOIN Component_PROPERTIES t7 ON (t7.Component_COMPONENTID = t6.COMPONENTID) 
                        WHERE ((t7.PROPERTIES_KEY = Capacity) AND t7.PROPERTIES LIKE 4GB%))))

一个标准有效，两个没有结果。

非常感谢任何帮助！

Answer 1

我要说的 mapJoin.key()应为compJoin.key()。

除此之外，我没有看到任何错误。

如果我提供的解决方案不起作用，这里有一些奖励问题：

你得到了什么结果？
是否可以显示生成的查询？

我发现有趣的一点： WHERE (((((t1.COMP_TYPE = ?) AND (t0.PROPERTIES_KEY = ?)) AND t0.PROPERTIES LIKE ?) AND (((t1.COMP_TYPE = ?) AND (t0.PROPERTIES_KEY = ?)) AND t0.PROPERTIES LIKE ?)) AND (t2.DTYPE = ?))

如果，我把这一点拿出来......只是为了澄清。 ((t1.COMP_TYPE = ?) AND (t0.PROPERTIES_KEY = ?))

WHERE (((SNIP AND t0.PROPERTIES LIKE ?) AND (SNIP AND t0.PROPERTIES LIKE ?)) AND (t2.DTYPE = ?))

所以是的...... 现在你将如何修复你的查询？可悲的是，我不是专家。但我所知道的是，如果您使用WHERE t2.CONF_ID IN (Subselect for criteria A) AND t2.CONF_ID IN (Subselect for criteria B)进行查询。

我的建议是查找子选项并滥用它们。 JPA 2.0, Criteria API, Subqueries, In Expressions解释了它，似乎足够相关。

jpa在查询2个mapjoins的字段时设置where子句

1 个答案: