MongoDB常用操作

关系型数据库名词与MongoDB对比：

命令行使用MongoDB

插入你的第一数据

> show databases

local 0.000GB

> use test #切换到test数据库，如果没有则新建

switched to db test

> show databases local 0.000GB

> db.demo.insert( { "key" : "value" } ) WriteResult({ "nInserted" : 1 })

> show databases local 0.000GB test 0.000GB

> show collections demo

> db.demo.findOne() { "_id" : ObjectId("573af7085ee4be80385332a6"), "key" : "value" }

python中使用MongoDB

import pymongo## client defaults to localhost and port 27017. eg MongoClient('localhost', 27017)client = pymongo.MongoClient()#连接到本地数据库blogDatabase = client[ "blog" ]     #切换到blog数据库usersCollection = blogDatabase[ "users" ]    #切换到usersCollectionusersCollection.insert_one( { "username" : "jdrumgoole","password" : "top secret","lang" : "EN" })#插入一条数据user = usersCollection.find_one()#查找最新的一条数据print( user )articlesCollection = blogDatabase[ "articles" ]author = "jdrumgoole"article = { "title" : "This is my first post","body" : "The is the longer body text for my blog post. We can add lots of text here.","author" : author,"tags" : [ "joe", "general", "Ireland", "admin" ]}## Lets check if our author exists#if usersCollection.find_one( { "username" : author }) :articlesCollection.insert_one( article )else:raise ValueError( "Author %s does not exist" % author )