“在哪里存在”在Hibernate HQL中 [英] "where exists" in Hibernate HQL

问题描述

如何在HQL中编写不存在查询？我试图获得一个不存在的HQL查询，它返回与此Oracle SQL查询相同的结果：

  select * 
从SCHOOL a 
不存在（从STUDENT中选择1 
 b 
其中B.SCHOOL_ID = a.id 
和B.STATUS_ID不在（0,1,2， 3,4））
  

我的映射文件如下：

 <！ - 主键ommitted  - > 
< set name =students
 cascade =allfetch =selectlazy =false> 
< key column =SCHOOL_ID/> 
 < / set> 
< / class> 
  

 <！ - 主键ommitted  - > 
 <多对一名称=学校
列=SCHOOL_ID
 class =com.companyname.Schoolfetch =joinlazy =false/> ; 
 
  class =com.companyname.Statuscolumn =STATUS_ID/> 
< / class> 
  

我在我的School.hbm.xml文件中尝试了以下标记：

 < query name =myQuery> 
 <！[CDATA [
 from School s不存在于学生st 
 where st.school_id = s.id and st.status.id not in（0,1,2， 3,4）
]]> 
< / query> 
  

我得到了这个堆栈跟踪

  org.springframework.beans.factory.BeanCreationException：在类路径资源[applicationContext.xml]中定义名称为'sessionFactory'的bean时出错：init方法的调用失败;嵌套异常是java.lang.NullPointerException 
由org.hibernate.hql.ast.HqlParser.negateNode（HqlParser.java:117）处的
导致：java.lang.NullPointerException 
。 hibernate.hql.antlr.HqlBaseParser.negatedExpression（HqlBaseParser.java:2378）
位于org.hibernate.hql.antlr.HqlBaseParser.logicalAndExpression（HqlBaseParser.java:2331）
位于org.hibernate.hql。 antlr.HqlBaseParser.logicalOrExpression（HqlBaseParser.java:2296）
 at org.hibernate.hql.antlr.HqlBaseParser.expression（HqlBaseParser.java:2082）
 at org.hibernate.hql.antlr.HqlBaseParser。逻辑表达式（HqlBaseParser.java:1858）
在org.hibernate.hql.antlr.HqlBaseParser.whereClause（HqlBaseParser.java:454）
在org.hibernate.hql.antlr.HqlBaseParser.queryRule（HqlBaseParser。 java：708）
 at org.hibernate.hql.antlr.HqlBaseParser.selectStatement（HqlBaseParser.java:296）
 at org.hibernate.hql.antlr.HqlBaseParser.statement（HqlB aseParser.java:159）
 at org.hibernate.hql.ast.QueryTranslatorImpl.parse（QueryTranslatorImpl.java:248）
 at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile（QueryTranslatorImpl.java： 
 at org.hibernate.engine.query.HQLQueryPlan。< init>（HQLQueryPlan.java:77）org.hibernate.hql.ast.QueryTranslatorImpl.compile（QueryTranslatorImpl.java:111）
 ）
在org.hibernate.engine.query.HQLQueryPlan。< init>（HQLQueryPlan.java:56）
在org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan（QueryPlanCache.java:72） 
 at org.hibernate.impl.SessionFactoryImpl.checkNamedQueries（SessionFactoryImpl.java:402）
 at org.hibernate.impl.SessionFactoryImpl。< init>（SessionFactoryImpl.java:352）
  

有人能让我知道我做错了什么吗？

c>不是 Student 实体）的属性，从而防止 SessionFactory 被实例化。你需要考虑对象和关联，而不是列。试试这个：

  from School作为s 
不存在（
 from Student as st 
 where st.school = s 
和st.status.id不在（0,1,2,3,4）
）
   
 $ b $ h 
 
 
 $ b 
 Hibernate核心参考指南
 
 
 
 
  14.13。子查询 
 
 
 
 
  
How can I write a "not exists" query in HQL? I am trying to get an HQL not exists query which returns the same results as this Oracle SQL query:
select *
from SCHOOL a
where not exists (select 1
from STUDENT b
where B.SCHOOL_ID=a.id
and B.STATUS_ID not in (0,1,2,3,4))
My mapping files are below:


    
  <!-- primary key ommitted -->
<set name="students"
     cascade="all" fetch="select" lazy="false" >
    <key column="SCHOOL_ID" />
    <one-to-many class="com.companyname.Student" />
</set>
</class>

   
  <!-- primary key ommitted -->
 <many-to-one name="school" 
              column="SCHOOL_ID"
              class="com.companyname.School" fetch="join" lazy="false"/>

 <many-to-one name="status"
        class="com.companyname.Status" column="STATUS_ID" />
</class>

   
      
       
      
      
   

I tried the following  tag in my School.hbm.xml file
<query name="myQuery">
    <![CDATA[
    from School s where not exists from Student st
    where st.school_id=s.id and st.status.id not in (0,1,2,3,4)
    ]]>
</query>
and I got this stack trace
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory' defined in class path resource [applicationContext.xml]: Invocation of init method failed; nested exception is java.lang.NullPointerException
Caused by: java.lang.NullPointerException
        at org.hibernate.hql.ast.HqlParser.negateNode(HqlParser.java:117)
        at org.hibernate.hql.antlr.HqlBaseParser.negatedExpression(HqlBaseParser.java:2378)
        at org.hibernate.hql.antlr.HqlBaseParser.logicalAndExpression(HqlBaseParser.java:2331)
        at org.hibernate.hql.antlr.HqlBaseParser.logicalOrExpression(HqlBaseParser.java:2296)
        at org.hibernate.hql.antlr.HqlBaseParser.expression(HqlBaseParser.java:2082)
        at org.hibernate.hql.antlr.HqlBaseParser.logicalExpression(HqlBaseParser.java:1858)
        at org.hibernate.hql.antlr.HqlBaseParser.whereClause(HqlBaseParser.java:454)
        at org.hibernate.hql.antlr.HqlBaseParser.queryRule(HqlBaseParser.java:708)
        at org.hibernate.hql.antlr.HqlBaseParser.selectStatement(HqlBaseParser.java:296)
        at org.hibernate.hql.antlr.HqlBaseParser.statement(HqlBaseParser.java:159)
        at org.hibernate.hql.ast.QueryTranslatorImpl.parse(QueryTranslatorImpl.java:248)
        at org.hibernate.hql.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:157)
        at org.hibernate.hql.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:111)
        at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:77)
        at org.hibernate.engine.query.HQLQueryPlan.<init>(HQLQueryPlan.java:56)
        at org.hibernate.engine.query.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:72)
        at org.hibernate.impl.SessionFactoryImpl.checkNamedQueries(SessionFactoryImpl.java:402)
        at org.hibernate.impl.SessionFactoryImpl.<init>(SessionFactoryImpl.java:352)
Can somebody let me know what I'm doing wrong?

Thank you!
解决方案
Your named query is not valid (school_id is not a property of the Student entity), which prevents the SessionFactory from being instantiated. You need to think object and associations, not columns. Try this instead:
from School as s
where not exists (
  from Student as st
  where st.school = s
  and st.status.id not in (0,1,2,3,4)
)


References


Hibernate Core Reference Guide


14.13. Subqueries 



                        
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