node.js学习（二十三、mongodb命令）

1.打开mongodb shell窗口

[root@iZ94b9jaqbfZ bin]# cd /usr/mongodb-linux-x86_64-3.4.3/bin
[root@iZ94b9jaqbfZ bin]# ls
bsondump  mongod        mongodump    mongofiles   mongooplog  mongoreplay   mongos     mongotop
mongo     mongodb.conf  mongoexport  mongoimport  mongoperf   mongorestore  mongostat
[root@iZ94b9jaqbfZ bin]# ./mongo
MongoDB shell version v3.4.3
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.3
Server has startup warnings:
2017-04-03T20:21:01.683+0800 I STORAGE  [initandlisten]
2017-04-03T20:21:01.683+0800 I STORAGE  [initandlisten] ** WARNING: Using the XFS filesystem is strongly recommended with the WiredTiger storage engine
2017-04-03T20:21:01.683+0800 I STORAGE  [initandlisten] **          See http://dochub.mongodb.org/core/prodnotes-filesystem 2017-04-03T20:21:03.058+0800 I CONTROL  [initandlisten]
2017-04-03T20:21:03.059+0800 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2017-04-03T20:21:03.059+0800 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2017-04-03T20:21:03.059+0800 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2017-04-03T20:21:03.059+0800 I CONTROL  [initandlisten]
2017-04-03T20:21:03.062+0800 I CONTROL  [initandlisten]
2017-04-03T20:21:03.062+0800 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 1024 processes, 65535 files. Number of processes should be at least 32767.5 : 0.5 times number of files.
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2.创建使用数据库

use DBNAME 当库不存在时会创建

> use test
switched to db test
> show dbs
admin  0.000GB
local  0.000GB

show dbs查看所有数据库，但是新创建的数据库不会被列出，当其中至少有一条数据时才回被列出。

> db.abc.insert({"key":"test","val":"这是一条测试数据"})
WriteResult({ "nInserted" : 1 })
> show dbs
admin  0.000GB
local  0.000GB
test   0.000GB

插入数据后正常显示

3.删除数据库

db.dropDatabase()删除数据库

> db.dropDatabase()
{ "dropped" : "test", "ok" : 1 }

db.collection.drop() 删除某一集合数据

> db.abc.drop()
true

3.向集合中插入数据（对象，不能插入字符串、数字等）

> db.abc.insert({"key":"test","val":"这是一条测试数据"})
WriteResult({ "nInserted" : 1 })
> db.abc.insert({"key":"test","val":"这是一条测试数据"})
WriteResult({ "nInserted" : 1 })
> db.abc.find()
{ "_id" : ObjectId("58e24b2ad14f02725996ff07"), "key" : "test", "val" : "这是一条测试数据" }
{ "_id" : ObjectId("58e24bc2d14f02725996ff08"), "key" : "test", "val" : "这是一条测试数据" }

4.查询、更新、删除

> db.abc.find()
{ "_id" : ObjectId("58e24b2ad14f02725996ff07"), "key" : "test", "val" : "这是一条测试数据" }
{ "_id" : ObjectId("58e24bc2d14f02725996ff08"), "key" : "test", "val" : "这是一条测试数据" }
> db.abc.find({ "_id" : ObjectId("58e24b2ad14f02725996ff07")})
{ "_id" : ObjectId("58e24b2ad14f02725996ff07"), "key" : "test", "val" : "这是一条测试数据" }
> db.abc.update({ "_id" : ObjectId("58e24b2ad14f02725996ff07")},{$set:{'val':"aaa"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.abc.find({ "_id" : ObjectId("58e24b2ad14f02725996ff07")})
{ "_id" : ObjectId("58e24b2ad14f02725996ff07"), "key" : "test", "val" : "aaa" }
> db.abc.remove({ "_id" : ObjectId("58e24b2ad14f02725996ff07")})
WriteResult({ "nRemoved" : 1 })
> db.abc.find({ "_id" : ObjectId("58e24b2ad14f02725996ff07")})
> db.abc.find()
{ "_id" : ObjectId("58e24bc2d14f02725996ff08"), "key" : "test", "val" : "这是一条测试数据" }