MongoDB常用用法

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本文转自 http://my.oschina.net/Kenyon/blog/99742

一、MongoDB的shell登陆

[mongo @localhost ~]$ mongo 
MongoDB shell version: 2.2.2 
connecting to: test 
>

二、查看现有的数据库

> show dbs;
local   (empty)
test    0.203125GB

三、数据库切换

> use local;
switched to db local
> use test;
switched to db test
>

四、显示collctions (感觉和DBMS的table比较像，但差别很大)

> show collections;
kenyon
system.indexes
test
things
>

五、数据插入

方式一(save)：
> db.kenyon.save({id:8899,name:'kenyon_test_mongo'});
> db.kenyon.save({id:99,name:'kenyon_test_mongo',remark:'first time here'});

方式二(预定义)：
> tmp={id:0909,name:'kenyon_test',create_time:'2013-01-01'};
> db.kenyon.insert(tmp);

方式三(循环插)：
> for (var i = 1; i <= 25; i++) db.tab_kenyon.insert( { x : 4 , j : i } )
> db.tab_kenyon.find();
{ "_id" : ObjectId("50e4b8007a86419166fd68f0"), "x" : 4, "j" : 1 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f1"), "x" : 4, "j" : 2 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f2"), "x" : 4, "j" : 3 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f3"), "x" : 4, "j" : 4 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f4"), "x" : 4, "j" : 5 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f5"), "x" : 4, "j" : 6 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f6"), "x" : 4, "j" : 7 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f7"), "x" : 4, "j" : 8 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f8"), "x" : 4, "j" : 9 }
{ "_id" : ObjectId("50e4b8007a86419166fd68f9"), "x" : 4, "j" : 10 }
{ "_id" : ObjectId("50e4b8007a86419166fd68fa"), "x" : 4, "j" : 11 }
{ "_id" : ObjectId("50e4b8007a86419166fd68fb"), "x" : 4, "j" : 12 }
{ "_id" : ObjectId("50e4b8007a86419166fd68fc"), "x" : 4, "j" : 13 }
{ "_id" : ObjectId("50e4b8007a86419166fd68fd"), "x" : 4, "j" : 14 }
{ "_id" : ObjectId("50e4b8007a86419166fd68fe"), "x" : 4, "j" : 15 }
{ "_id" : ObjectId("50e4b8007a86419166fd68ff"), "x" : 4, "j" : 16 }
{ "_id" : ObjectId("50e4b8007a86419166fd6900"), "x" : 4, "j" : 17 }
{ "_id" : ObjectId("50e4b8007a86419166fd6901"), "x" : 4, "j" : 18 }
{ "_id" : ObjectId("50e4b8007a86419166fd6902"), "x" : 4, "j" : 19 }
{ "_id" : ObjectId("50e4b8007a86419166fd6903"), "x" : 4, "j" : 20 }
Type "it" for more
> it
{ "_id" : ObjectId("50e4b8737a86419166fd6904"), "x" : 4, "j" : 21 }
{ "_id" : ObjectId("50e4b8737a86419166fd6905"), "x" : 4, "j" : 22 }
{ "_id" : ObjectId("50e4b8737a86419166fd6906"), "x" : 4, "j" : 23 }
{ "_id" : ObjectId("50e4b8737a86419166fd6907"), "x" : 4, "j" : 24 }
{ "_id" : ObjectId("50e4b8737a86419166fd6908"), "x" : 4, "j" : 25 }

如果不存在collection会自动创建，不会报错，显示数据时默认是显示20条数据，输入it来查看下一页的20条数据

六、数据检索
1. 普通方式

> db.kenyon.find();
{ "_id" : ObjectId("50e49c55f8de48037fe44062"), "name" : "mongo" }
{ "_id" : ObjectId("50e49d2ecd320366f7122605"), "name" : "mongo", "id" : "888" }
{ "_id" : ObjectId("50e4b3fe7a86419166fd68ed"), "id" : 8899, "name" : "kenyon_test_mongo" }
{ "_id" : ObjectId("50e4b4167a86419166fd68ee"), "id" : 99, "name" : "kenyon_test_mongo", "remark" : "first time here" }
{ "_id" : ObjectId("50e4b6817a86419166fd68ef"), "id" : 909, "name" : "kenyon_test", "create_time" : "2013-01-01" }

2.查询一条数据

> db.kenyon.findOne();
{ "_id" : ObjectId("50e49c55f8de48037fe44062"), "name" : "mongo" }

3.条件检索

> db.kenyon.find();
{ "_id" : ObjectId("50e49c55f8de48037fe44062"), "name" : "mongo" }
{ "_id" : ObjectId("50e49d2ecd320366f7122605"), "name" : "mongo", "id" : "888" }
{ "_id" : ObjectId("50e4b3fe7a86419166fd68ed"), "id" : 8899, "name" : "kenyon_test_mongo" }
{ "_id" : ObjectId("50e4b4167a86419166fd68ee"), "id" : 99, "name" : "kenyon_test_mongo", "remark" : "first time here" }
{ "_id" : ObjectId("50e4b6817a86419166fd68ef"), "id" : 909, "name" : "kenyon_test", "create_time" : "2013-01-01" }

> db.kenyon.find({id:909});
{ "_id" : ObjectId("50e4b6817a86419166fd68ef"), "id" : 909, "name" : "kenyon_test", "create_time" : "2013-01-01" }

> db.kenyon.find({name:"mongo"});
{ "_id" : ObjectId("50e49c55f8de48037fe44062"), "name" : "mongo" }
{ "_id" : ObjectId("50e49d2ecd320366f7122605"), "name" : "mongo", "id" : "888" }

4.限制查询(limit)

> db.kenyon.find().limit(2)
{ "_id" : ObjectId("50e49c55f8de48037fe44062"), "name" : "mongo" }
{ "_id" : ObjectId("50e49d2ecd320366f7122605"), "name" : "mongo", "id" : "888" }

七、mongo的shell帮助

> help
        db.help()                    help on db methods
        db.mycoll.help()             help on collection methods
        sh.help()                    sharding helpers
        rs.help()                    replica set helpers
        help admin                   administrative help
        help connect                 connecting to a db help
        help keys                    key shortcuts
        help misc                    misc things to know
        help mr                      mapreduce

        show dbs                     show database names
        show collections             show collections in current database
        show users                   show users in current database
        show profile                 show most recent system.profile entries with time >= 1ms
        show logs                    show the accessible logger names
        show log [name]              prints out the last segment of log in memory, 'global' is default
        use                 set current database
        db.foo.find()                list objects in collection foo
        db.foo.find( { a : 1 } )     list objects in foo where a == 1
        it                           result of the last line evaluated; use to further iterate
        DBQuery.shellBatchSize = x   set default number of items to display on shell
        exit                         quit the mongo shell
>