如何从嵌入文档的键值类型中得到准确的文档结果

Question

假设我有这种文档结构，属性字段将是嵌入的文档我已经索引了属性。键和属性。value

1-------------------------------------------------------------------------------------
{ 
  "_id" : ObjectId( "5191d8e5d00560402e000001" ),
  "attributes" : [ 
  { "key" : "pobox","value" : "QaKUWo" }, 
  { "key" : "city", "value" : "CBDRip" }, 
  { "key" : "address","value" : "zmycAa" } ],
  "email" : "[e-mail]",
  "firstname" : "FWAUdl_2" 
}
2-------------------------------------------------------------------------------------
{ 
  "_id" : ObjectId( "5191d8e7d00560402e000055" ),
  "attributes" : [ 
    { "key" : "pobox", "value" : "sNFriy" }, 
    { "key" : "city", "value" : "JPdVrI" }, 
    { "key" : "address", "value" : "phOluW" } ],
  "email" : "[e-mail]",
  "firstname" : "hqYNWH_86" 
}

我的问题是如何获得准确的文档时，查询仅基于属性字段，

db.app.find({ attributes.key:address , attributes.value:/.*uw.*/i })

查询结果不像我期望的那样，它应该只产生第二个文档，而不产生第一个文档。我知道我在属性上放了正则表达式。值，我期望它只检查属性。有地址值的键。

如果我想过滤另一个键，比如

db.app.find({ attributes.key:address , attributes.value:/.*uw.*/i , attributes.key:city , attributes.value:/.*ri.*/i })

任何意见都会对你们有帮助的。Thx .

Answer 1

我猜你需要$elemMatch (http://docs.mongodb.org/manual/reference/operator/elemMatch/)

db.test123.find({ attributes : { $elemMatch : { 'key':"address" , 'value':/.*uw.*/i } } }).pretty()
{
    "_id" : ObjectId("5191d8e7d00560402e000055"),
    "attributes" : [
        {
            "key" : "pobox",
            "value" : "sNFriy"
        },
        {
            "key" : "city",
            "value" : "JPdVrI"
        },
        {
            "key" : "address",
            "value" : "phOluW"
        }
    ],
    "email" : "[e-mail]",
    "firstname" : "hqYNWH_86"
}

Answer 2

只是调查了一下，得出了以下结论。下面使用下面提到的索引。您可以在find()上执行explain()来查看更多索引使用细节

db.testing.getIndexKeys()
[ { "_id" : 1 }, { "attributes.key" : 1, "attributes.value" : 1 } ]
test:Mongo > db.testing.find({$and : [ { attributes : {$elemMatch : {key : 'address', value : /.*uw.*/i }} }, { attributes : {$elemMatch : {key : 'city', value : /.*ri.*/i }} }] }).pretty()
{
    "_id" : ObjectId("5191d8e7d00560402e000055"),
    "attributes" : [
        {
            "key" : "pobox",
            "value" : "sNFriy"
        },
        {
            "key" : "city",
            "value" : "JPdVrI"
        },
        {
            "key" : "address",
            "value" : "phOluW"
        }
    ],
    "email" : "[e-mail]",
    "firstname" : "hqYNWH_86"
}