MongoDB + C#驱动程序+元素查询数组，其中每个数组元素包含要查询的子文档 [英] MongoDB + C# driver + query array of elements where each array element contains sub-document to query on

问题描述

我使用的是MongoDB C#官方驱动程序的1.5.0.4566版本.我正在使用Mongo 2.06版.

I'm using version 1.5.0.4566 of the official MongoDB C# driver. I'm using Mongo version 2.06.

这是我的文档结构的样子(此讨论中不需要省略字段):

Here is what my document structure looks like (omitted fields not necessary for this discussion):

{ "Parents" : 
   [ 
     {
     "CreatedOn": ISODate("2012-07-28T15:30:06.623Z"),
     "Title": "Simple Title",
     "Children": [   
                  { "StatusId": 1, "Active" : true, SubChild : { "ExpiresOn": ISODate("2012-07-28T15:30:06.623Z")}},
                  { "StatusId": 1, "Active" : true, SubChild : { "ExpiresOn": ISODate("2012-08-28T15:30:06.623Z")}}
                 ]
     },
     {
     "CreatedOn": ISODate("2012-07-28T15:30:06.623Z"),
     "Title": "Another Simple Title",
     "Children": [   
                  { "StatusId": 1, "Active" : true, SubChild : { "ExpiresOn": ISODate("2012-07-28T15:30:06.623Z")}},
                  { "StatusId": 1, "Active" : true, SubChild : { "ExpiresOn": ISODate("2012-08-28T15:30:06.623Z")}}
                 ]
     }
   ]
}

如果我要查询StatusId等于1并且Active为true的Children，则可以使用ElemMatch.

If I wanted to query the Children that have a StatusId equal to one and Active is true I can use ElemMatch.

Query.ElemMatch("Children", Query.And(Query.EQ("StatusId", 1),Query.EQ("Active",true)));

当需要在查询中包括SubChild元素时，我无法工作.

What I cannot get to work is when I need to include the SubChild element in my query.

Query.ElemMatch("Children", Query.And(Query.EQ("StatusId",1), Query.EQ("Active",true),Query.LT("SubChild.ExpiresOn",DateTime.UtcNow)));

当我尝试在查询中包括SubChild.ExpiresOn字段时，查询不返回任何值.我尝试了不同的方式来构建此查询，但是当我包含SubChild.ExpiredOn字段时，始终获得零文档.

The query doesn't return any values when I try to include the SubChild.ExpiresOn field in the query. I have tried different ways to build this query, but keep getting zero documents when I include the SubChild.ExpiredOn field.

我想念什么?

谢谢

推荐答案

尝试尝试

Query.ElemMatch("Children", Query.And(Query.EQ("StatusId",1), Query.EQ("Active",true),Query.LT("SubChild.ExpiresOn",DateTime.UtcNow)));

奇怪为什么这个查询神奇地起作用了?就是这种情况(StatusId与StatusID). JavaScript区分大小写.

Wondering why this query magically works? It's the case (StatusId vs StatusID). JavaScript is case sensitive.

您可以通过使用强类型的Linq查询来消除此问题，例如:

You could eliminate this problem by using strongly typed Linq queries, like:

from x in collection.AsQueryable()
where x.Children.Any(child => 
    child.StatusId == 1 
    && child.Active 
    && child.SubChild.ExpiresOn < DateTime.UtcNow)
select x

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