基本概念

  • MongoDB: an open-source document database
  • ORM: Object Relational Mapping
  • Documents: a record in MongoDB, similar to JSON objects
  • Collections: MongoDB stores documents in collections, analogous to tables in relational databases
  • _id field: unique, acts as a primary key
  • JSON: JavaScript Object Notation
  • BSON: a binary representation of JSON documents
  • CRUD: create, read, update, and delete documents
  • drivers: an application communicates with MongoDB by way of a client library, including shell, python, C, java, Node.js, etc. :–

    与关系型数据库（RDBMS）类比

Terminology

RDBMS MongoDB
Database Database
Table Collection
Tuple/Row Document
column Field
Table Join Embedded Documents
Primary key Primary Key (Default key _id provided by mongodb itself)

Deatabase Server and Client

RDBMS MongoDB
Mysqld/Oracle mongod
mysql/sqlplus mongo

MongoDB Package Componets

  • mongod: the primary daemon process(守护进程) for the MongoDB system
  • mongos: MongoDB Shard. Sharding means a method for distributing data across multiple machines.
  • mongo: an interactive JavaScript shell interface to MongoDB
  • mongodump: a utility for creating a binary export of the contents of a database
  • mongorestore: writes data from a binary database dump created by mongodump to a MongoDB instance.
  • bsondump: converts BSON files into human-readable formats, including JSON.
  • mongooplog: a simple tool that polls operations from the replication oplog of a remote server, and applies them to the local server.
  • mongoimport: imports content from an Extended JSON, CSV, or TSV export created by mongoexport, or potentially, another third-party export tool.
  • mongoexport: a utility that produces a JSON or CSV export of data stored in a MongoDB instance.
  • mongostat: provides a quick overview of the status of a currently running mongod or mongos instance
  • mongotop: provides a method to track the amount of time a MongoDB instance spends reading and writing data
  • mongosniff: provides a low-level operation tracing/sniffing view into database activity in real time
  • mongoperf: a utility to check disk I/O performance independently of MongoDB
  • mongofiles: makes it possible to manipulate files stored in your MongoDB instance in GridFS objects from the command line.

MongoDB CRUD Operations

Create Operations

add new documents to a collection

db.collection.insert()
db.collection.insertOne()
db.collection.insertMany()

Read Operations

read documents from a collection, i.e. queries a collection for documents

db.collection.find()
Query Filter Description
{} 所有documents
{a: 10} a filed值为10的documents
{a: {$gt: 10}} a值大于10的documents。更多见comparison query operators文档。如$eq, $gt, $gte, lt, lte, etc.
{a: 10, b: "hello"} a值为10且b值为“hello”的documents
{a: {$in: [10,"hello"]}} a值为10或为“hello”的documents
{$or: [{a: 10}, {b: "hello"}]} a值为10或b值为“hello”的documents
{a: {$all: [10, "hello"]}} a是一个含有10和“hello”的数组的documents
{"a.b": 10} a是一个embedded document，且b值为10的documents
{a: /^m/} or {a: {$regex: "^m"}} a开头字母为m的documents
{a: {$type: 2}} a为字符串类型的documents。注此处2为BSON type number。详情见文档

更多见文档：Query Documents

Update Operations

modify existing documents in a collection

db.collection.update()
db.collection.updateOne()
db.collection.updateMany()
db.collection.replaceOne()

Delete Operations

remove documents from a collection

db.collection.remove()
db.collection.deleteOne()
db.collection.deleteMany()

Mongo by Python

  • 安装pymongo
$ pip install pymongo
  • 导入pymongo
from pymongo import MongoClient
  • 创建一个connection
client = MongoClient() #默认是localhost，端口27017
client = MongoClient("mongodb://mongodb0.example.net:27017")

mongo的客户端

  • mongochef
  • robomongo

扩展阅读：