16 }
{ "_id" : ObjectId("55bec43732cbb5faa25c967d"), "name" : "yuan", "age" : "23" }
>
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7.3 向集合中的某个文档添加字段 push
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> db.LABELNET.update({"name":"yuan"},{$push:{"csdnBlog":"http://blog.csdn.net/la
blenet"}});
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55bec43732cbb5faa25c967d"), "name" : "yuan", "age" : "23", "
csdnBlog" : [ "http://blog.csdn.net/lablenet" ] }
>
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8.删除操作 remove
8.1 基本格式
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（1）db.集合名称.remove(where); 条件删除
（2） db.集合名称.remove(); 删除全部记录
（3） db.集合名称.drop(); 删除全部文档（document）
8.2 演示示例 ：条件删除
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> db.LABELNET.remove({"name":"yuan"});
WriteResult({ "nRemoved" : 1 })
> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
>
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9. 其他操作
9.1 先准备数据
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> db.LABELNET.insert({"name":"yuan","age":23});
WriteResult({ "nInserted" : 1 })
> db.LABELNET.insert({"name":"ming","age":10});
WriteResult({ "nInserted" : 1 })
> db.LABELNET.insert({"name":"zhuo","age":30});
WriteResult({ "nInserted" : 1 })
> db.LABELNET.insert({"name":"hpu","age":30});
WriteResult({ "nInserted" : 1 })
> db.LABELNET.find();
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
{ "_id" : ObjectId("55beca9f32cbb5faa25c9681"), "name" : "hpu", "age" : 30 }
>
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9.1 条件查询 —— > , < , >= ,<=
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（1） (>) 大于 - $gt
（2）(<) 小于 - $lt
（3）(>=) 大于等于 - $gte
（4）(<= ) 小于等于 - $lte
> db.LABELNET.find({"age":{"$gt":16}});
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
{ "_id" : ObjectId("55beca9f32cbb5faa25c9681"), "name" : "hpu", "age" : 30 }
> db.LABELNET.find({"age":{"$lt":16}});
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
> db.LABELNET.find({"age":{"$gte":16}});
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55beca3932cbb5faa25c967e"), "name" : "yuan", "age" : 23 }
{ "_id" : ObjectId("55beca5132cbb5faa25c9680"), "name" : "zhuo", "age" : 30 }
{ "_id" : ObjectId("55beca9f32cbb5faa25c9681"), "name" : "hpu", "age" : 30 }
> db.LABELNET.find({"age":{"$lte":16}});
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
{ "_id" : ObjectId("55beca4632cbb5faa25c967f"), "name" : "ming", "age" : 10 }
> db.LABELNET.find({"age":16});
{ "_id" : ObjectId("55bec40532cbb5faa25c967c"), "name" : "csdn", "age" : 16 }
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9.2 满足条件的条数 count
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> db.LABELNET.count({"age":30});
2
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9.3 得到所有key的value（去掉重复的） distinct
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> db.LABELNET.distinct("age");
[ 16, 23, 10, 30 ]
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9.4 查看集合的数据大小 dataSize ： 注意S 大写
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> db.LABELNET.dataSize();
560
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9.5 查看集合状态 stats
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> db.LABELNET.stats();
{
"ns" : "student.LABELNET",
"count" : 5,
"size" : 560,
"avgObjSize" : 112,
"numExtents" : 1,
"storageSize" : 8192,
"lastExtentSize" : 8192,
"paddingFactor" : 1,
"paddingFactorNote" : "paddingFactor is unused and unmaintained in 3.0.
It remains hard coded to 1.0 for compatibility only