MongoDB

MongoDB is a document database with the scalability and flexibility that you want with the querying and indexing that you need.

Features

MongoDB stores data in flexible, JSON-like documents, meaning fields can vary from document to document and data structure can be changed over time
The document model maps to the objects in your application code, making data easy to work with
Ad hoc queries, indexing, and real time aggregation provide powerful ways to access and analyze your data
MongoDB is a distributed database at its core, so high availability, horizontal scaling, and geographic distribution are built in and easy to use

Manual

教程zh_CN

为什么使用NoSQL?

今天我们可以通过第三方平台（如：Google,Facebook等）可以很容易的访问和抓取数据。用户的个人信息，社交网络，地理位置，用户生成的数据和用户操作日志已经成倍的增加。我们如果要对这些用户数据进行挖掘，那SQL数据库已经不适合这些应用了, NoSQL数据库的发展也却能很好的处理这些大的数据。

这句话深得我心。就是因为抓取百科信息，觉得全部入表太麻烦，如此才要尝试下 MangoDB。

CAP定理（CAP theorem）

在计算机科学中, CAP定理（CAP theorem）, 又被称作布鲁尔定理（Brewer’s theorem）, 它指出对于一个分布式计算系统来说，不可能同时满足以下三点:

一致性(Consistency) (所有节点在同一时间具有相同的数据)
可用性(Availability) (保证每个请求不管成功或者失败都有响应)
分隔容忍(Partition tolerance) (系统中任意信息的丢失或失败不会影响系统的继续运作)

cap

Install

本机为MAC。

下载地址

命令行方式

$   curl -O https://fastdl.mongodb.org/osx/mongodb-osx-ssl-x86_64-3.4.4.tgz

将 mangodb 的二进制命令目录添加到path

$   export PATH=~/bin:$PATH

brew

$   brew mongodb

安装速度比较慢。

根据安装日志，安装的路径在：

/usr/local/Cellar/mongodb/3.4.4/

加入环境变量

编辑

vi  ~/.bash_profile

加入

# 添加mongodb安装目录到环境变量中
export PATH=/usr/local/Cellar/mongodb/3.4.4/bin:${PATH}

立刻生效

source ~/.bash_profile

Run

mac 下用 brew 安装mongodb

修改配置

修改mongodb配置文件,配置文件默认在 /usr/local/etc 下的 mongod.conf

$ cat /usr/local/etc/mongod.conf 
systemLog:
  destination: file
  path: /usr/local/var/log/mongodb/mongo.log
  logAppend: true
storage:
  dbPath: /usr/local/var/mongodb
net:
  bindIp: 127.0.0.1

此处不做修改。保持默认。

首先我们创建一个数据库存储目录 /data/db：

sudo mkdir -p /data/db

运行

houbinbindeMacBook-Pro:bin houbinbin$ mongod
2017-06-01T22:34:19.719+0800 I CONTROL  [initandlisten] MongoDB starting : pid=6905 port=27017 dbpath=/data/db 64-bit host=houbinbindeMacBook-Pro.local
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten] db version v3.4.4
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten] git version: 888390515874a9debd1b6c5d36559ca86b44babd
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten] OpenSSL version: OpenSSL 1.0.2k  26 Jan 2017
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten] allocator: system
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten] modules: none
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten] build environment:
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten]     distarch: x86_64
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten]     target_arch: x86_64
2017-06-01T22:34:19.720+0800 I CONTROL  [initandlisten] options: {}
2017-06-01T22:34:19.721+0800 I STORAGE  [initandlisten] exception in initAndListen: 20 Attempted to create a lock file on a read-only directory: /data/db, terminating
2017-06-01T22:34:19.721+0800 I NETWORK  [initandlisten] shutdown: going to close listening sockets...
2017-06-01T22:34:19.721+0800 I NETWORK  [initandlisten] shutdown: going to flush diaglog...
2017-06-01T22:34:19.721+0800 I CONTROL  [initandlisten] now exiting
2017-06-01T22:34:19.721+0800 I CONTROL  [initandlisten] shutting down with code:100

如你所见，对于 /data/db 没有写入权限，导致程序终止。

给 /data/db 文件夹赋权限

chown `id -u` /data/db

重新运行，服务正常启动。

houbinbindeMacBook-Pro:bin houbinbin$ mongod
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten] MongoDB starting : pid=6931 port=27017 dbpath=/data/db 64-bit host=houbinbindeMacBook-Pro.local
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten] db version v3.4.4
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten] git version: 888390515874a9debd1b6c5d36559ca86b44babd
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten] OpenSSL version: OpenSSL 1.0.2k  26 Jan 2017
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten] allocator: system
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten] modules: none
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten] build environment:
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten]     distarch: x86_64
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten]     target_arch: x86_64
2017-06-01T22:38:10.149+0800 I CONTROL  [initandlisten] options: {}
2017-06-01T22:38:10.150+0800 I STORAGE  [initandlisten] wiredtiger_open config: create,cache_size=7680M,session_max=20000,eviction=(threads_min=4,threads_max=4),config_base=false,statistics=(fast),log=(enabled=true,archive=true,path=journal,compressor=snappy),file_manager=(close_idle_time=100000),checkpoint=(wait=60,log_size=2GB),statistics_log=(wait=0),
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] 
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] 
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] 
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000
2017-06-01T22:38:10.866+0800 I FTDC     [initandlisten] Initializing full-time diagnostic data capture with directory '/data/db/diagnostic.data'
2017-06-01T22:38:11.015+0800 I INDEX    [initandlisten] build index on: admin.system.version properties: { v: 2, key: { version: 1 }, name: "incompatible_with_version_32", ns: "admin.system.version" }
2017-06-01T22:38:11.015+0800 I INDEX    [initandlisten] 	 building index using bulk method; build may temporarily use up to 500 megabytes of RAM
2017-06-01T22:38:11.026+0800 I INDEX    [initandlisten] build index done.  scanned 0 total records. 0 secs
2017-06-01T22:38:11.027+0800 I COMMAND  [initandlisten] setting featureCompatibilityVersion to 3.4
2017-06-01T22:38:11.027+0800 I NETWORK  [thread1] waiting for connections on port 27017

启动客户端

另外打开一个命令行。执行

houbinbindeMacBook-Pro:etc houbinbin$ pwd
/usr/local/etc
houbinbindeMacBook-Pro:etc houbinbin$ mongo
MongoDB shell version v3.4.4
connecting to: mongodb://127.0.0.1:27017
MongoDB server version: 3.4.4
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
	http://docs.mongodb.org/
Questions? Try the support group
	http://groups.google.com/group/mongodb-user
Server has startup warnings: 
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] 
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] ** WARNING: Access control is not enabled for the database.
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] **          Read and write access to data and configuration is unrestricted.
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] 
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] 
2017-06-01T22:38:10.682+0800 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. Number of files is 256, should be at least 1000
> 

查询数据库，简单测试。

> show dbs
admin  0.000GB
local  0.000GB

MongoDB-01-install

MongoDB

为什么使用NoSQL?

Install

Run

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