{
"_id":{
"oid":"4f33bf69873dbc73a7d21dc3"
},
"country":"IND",
"states":[{
"name":"orissa",
"direction":"east",
"population":41947358,
"districts":[{
"name":"puri",
"headquarter":"puri",
"population":1498604
},
{
"name":"khordha",
"headquarter":"bhubaneswar",
"population":1874405
}
]
},
{
"name":"andhra pradesh",
"direction":"south",
"population":84665533,
"districts":[{
"name":"rangareddi",
"headquarter":"hyderabad",
"population":3506670
},
{
"name":"vishakhapatnam",
"headquarter":"vishakhapatnam",
"population":3789823
}
]
}
]
}
在上述集合(即國家)我只有一個文件,我想獲取有關特定狀態的詳細信息(可以說「country.states.name」:「奧里薩邦」) ,但我想我的結果作爲下在這裏,而不是整個文件。是那裏莫戈的方式...只選擇子文檔或陣列
{
"name": "orissa",
"direction": "east",
"population": 41947358,
"districts": [
{
"name": "puri",
"headquarter": "puri",
"population": 1498604
},
{
"name": "khordha",
"headquarter": "bhubaneswar",
"population": 1874405
}
]
}
感謝
那麼我們可以在Mongo中編寫一個程序,我們可以先獲得狀態的序號然後使用$ slice? – John 2012-02-15 10:24:09
@John:不,但可以在將國家插入數據庫時將'id'添加到每個狀態等於序號的狀態。然後使用這個ID來加載特定的狀態。 – 2012-02-15 10:34:28