mongodb创建数据库

查看所有的数据库

> show db
Admin  0.078GB
cric   0.078GB
local  0.078GB
test   0.078GB

查看当前库

> db
test

切换，如果库存在，则切换，如果不存在，则创建后切换

> show dbsshow dbs
Admin  0.078GB
cric   0.078GB
local  0.078GB
test   0.078G
> use cric
switched to db cric
> db
cric
> use cric01
switched to db cric01
> db
cric01

刚创建的库没有集合时，show dbs时不显示，创建至少一个集合后才会显示

> db
cric01
> show dbsshow dbs
Admin  0.078GB
cric   0.078GB
local  0.078GB
test   0.078GB
> db.createCollection("c1")
{ "ok" : 1 }
> show dbs
Admin   0.078GB
cric    0.078GB
cric01  0.078GB
local   0.078GB
test    0.078GB

说明：

1、库Admin、local和test为系统自带的数据库

2、连接时可指定数据库，如不指定数据库，默认到test数据库

mongo admin
MongoDB shell version: 3.0.5
connecting to: local
Server has startup warnings:
2015-08-20T14:51:32.874+0800 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2015-08-20T14:51:32.874+0800 I CONTROL  [initandlisten]
> db
admin

mongo
MongoDB shell version: 3.0.5
connecting to: test
Server has startup warnings:
2015-08-20T14:51:32.874+0800 I CONTROL  [initandlisten] ** WARNING: You are running this process as the root user, which is not recommended.
2015-08-20T14:51:32.874+0800 I CONTROL  [initandlisten]
> db
test