数据库 > tmp
集合 > app_down
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> use tmp
switched to db tmp
R:使用tmp数据库
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> db.createCollection("app_down");
{ "ok" : 1 }
R:创建集合
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> db.app_down.save({"app_id":1002,"count_down":33,"stat_date":"2014-01-01"});
> db.app_down.save({"app_id":1102,"count_down":33,"stat_date":"2014-01-02"});
> db.app_down.save({"app_id":1100,"count_down":33,"stat_date":"2014-01-02"});
R:模拟测试数据
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> db.app_down.find();
{ "_id" : ObjectId("534f72c0c7f347b9e5b44efc"), "app_id" : 1002, "count_down" : 33, "stat_date" : "2014-01-01" }
{ "_id" : ObjectId("534f72cac7f347b9e5b44efd"), "app_id" : 1102, "count_down" : 33, "stat_date" : "2014-01-02" }
{ "_id" : ObjectId("534f72cec7f347b9e5b44efe"), "app_id" : 1100, "count_down" : 33, "stat_date" : "2014-01-02" }
R:查询所有数据
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> db.app_down.getIndexes();
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "tmp.app_down",
"name" : "_id_"
}
]
R: 查询集合索引列表,插入数据时默认会给_id创建"升序"索引,在find()中不排序情况下默认是按照_id"升序" 排序
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> db.app_down.find({app_id:1100}).explain();
{
"cursor" : "BasicCursor",
"isMultiKey" : false,
"n" : 1,
"nscannedObjects" : 3,
"nscanned" : 3,
"nscannedObjectsAllPlans" : 3,
"nscannedAllPlans" : 3,
"scanAndOrder" : false,
"indexOnly" : false,
"nYields" : 0,
"nChunkSkips" : 0,
"millis" : 0,
"indexBounds" : {
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},
"server" : "tts-0001:27017"
}
R:查询分析 cursor索引类型,BasicCursor没有使用索引,
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> db.app_down.ensureIndex({app_id:1});
R:给字段app_id创建升序索引
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> db.app_down.getIndexes();
[
{
"v" : 1,
"key" : {
"_id" : 1
},
"ns" : "tmp.app_down",
"name" : "_id_"
},
{
"v" : 1,
"key" : {
"app_id" : 1
},
"n
