Grails 2.5.1（hibernate 3）标准多个连接到同一个表 [英] Grails 2.5.1 (hibernate 3) criteria multiple joins to same table

问题描述

  class SomeDomain {
 static hasMany = [productData ：ProductData] 
} 
  

ProductData是简单的类型/值对

我试图找到具有某种类型的多个产品的所有SomeDomains（在一个循环中）。目前标准的相关部分如下所示：

  SomeDomain.createCriteria.list {
 somedata.each {type，价值 - > 
 productData {
 eq（type，type）
 eq（value，value）
} 
} 
} 
  

但是，这只会产生一个SQL连接：

<$来自some_domain的内部加入product_data productdata_a1_ this_.id = productdata_a1_.some_domain_id
其中（productdata_a1_.type_id = 4和productdata_a1_.value ='GC'）
和（productdata_a1_.type_id = 5和productdata_a1_.value ='P1'）

显然type_id永远不会成功和检查= 4和= 5 ...

我真的很喜欢两个内部联接到product_data ...无法弄清楚我尝试了
createAlias（productData，product - $ {index}）
这给了
org.hibernate.QueryException：重复关联路径：productData

解决方案

不确定为什么需要多个连接到同一个表？如果问题被正确理解，那么

  String query =from someDomain sd join productData pd其中pd.type in（：types）和pd .value in（：values）
 def inputParams = [：] 
 inputParams.values = ['GC'，'P1'] 
 inputParams.types = [4,5] 
 List resultsList = SomeDomain.executeQuery（query，inputParams，[readOnly：true，timeout：15]）
  

pd.type可能必须是另一个连接，因为它在调试时会尝试获取.id所以添加另一个连接

 字符串query =来自someDomain sd join productData pd join pd.types tp其中tp.id in（：types）和pd.value in（：values）
  

如果您想按照问题中的建议进行多次连接，请按照以下步骤操作：

 字符串查询=从someDomain sd加入productData pd加入pd.types tp，ProductData pd2其中tp.id in（：types）和pd.value in（：values）and pd2.something = pd.something
  

接下来就是了f并查找链接到someDomain的productData，然后再次查找整个 ProductData作为pd2 ，然后确认 pd2.something = pd.something


在HQL中使用逗号变成与现有查询无关的新查找。

I've found similar questions, but no answers.

class SomeDomain {
    static hasMany= [productData:ProductData]
}

ProductData is simple type/value pair

I'm trying to find all SomeDomains that have multiple products of certain type (in a loop). Currently the relevant portion of the criteria looks like:

SomeDomain.createCriteria.list {
  somedata.each { type, value ->
    productData {
      eq("type", type)
      eq("value", value)
    }
  }
}

However, this generates only a single join with the SQL:

from some_domain this_ inner join product_data productdata_a1_ on this_.id=productdata_a1_.some_domain_id 
where (productdata_a1_.type_id=4 and productdata_a1_.value='GC') 
and (productdata_a1_.type_id=5 and productdata_a1_.value='P1') 

obviously type_id is never going to succeed on and'd checks for =4 and =5...

What I'd really like is two inner joins to product_data... can't figure out how to force this, though.

I tried createAlias("productData", "product-${index}") this gave org.hibernate.QueryException: duplicate association path: productData

解决方案

Unsure why you need multiple joins to same table ? if question is understood correctly

String query="from someDomain sd join productData pd where pd.type in (:types) and pd.value in (:values) "
def inputParams=[:]
inputParams.values=['GC','P1']
inputParams.types=[4,5]
List resultsList = SomeDomain.executeQuery(query,inputParams,[readOnly:true,timeout:15])

pd.type may have to be another join since in the debug it attempts to get the .id so add another join

  String query="from someDomain sd join productData pd join pd.types tp where tp.id in (:types) and pd.value in (:values) "

If you wanted to do multiple joins as suggested in the question

  String query="from someDomain sd join productData pd join pd.types tp, ProductData pd2 where tp.id in (:types) and pd.value in (:values) and pd2.something=pd.something"

That is then going off and looking productData that is linked to someDomain then again looking up entire ProductData as pd2 and then confirming where pd2.something = pd.something

Using comma's in HQL becomes a new lookup not related to existing query..

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