A, mongoDB introduction and use of
1, the distributed file storage database, developed in C ++, can store any data (files), allowing the server side script that uses data stored as JSON {key: value}
2, supported programming languages: PHP, ruby, python, C ++, C #, Java, etc.
3, represents the current database using db
4, the installation: apt install mongodb / source installation
5, run: mongo enable the port 27017
6, management tools: NoSQL Manager for MongoDB, Navicat
Two, MongoDB some of the concepts:
database database
Data collection set (Table)
document file (line)
field field (column)
index index
Does not support table join
Database ----> collection ----> Documents ----> domain
MongoDB can have a plurality of databases, different databases can be placed in different files
System database:
admin: equivalent to the root database, which is a database of high authority, all of the commands can be executed in the database
local: a collection of local server storage
config: related to the fragmentation of the database
Third, the commonly used commands:
View all databases show dbs
use admin switch databases
db current database
use the database name to create the database
db.dropDatabase () to delete the database currently in use
db.createCollection ( 'the collection name') create a collection
db. collectionname .drop () return value is a Boolean delete collections
show collections View collections
db collection name .insert ({key1: value1, key2: value2}). create documents, k1 and k2 are domains, v1 and v2 are values corresponding to the domain
db.users.find().pretty() 查看users集合下的所有数据
四、数据类型
布尔
数字
字符
浮点数
数组
内嵌文档
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