Getting started with mongodb

MongoDB brief introduction

MongoDB Is a database based on distributed file storage . from C++ Language writing , For the purpose of WEB Applications provide scalable, high-performance data storage solutions .

MongoDB Is a product between relational and non-relational databases （ Definition or non relational database ）, Yes no relational database has the most functions , Most like a relational database . The data structure it supports is very loose , Is similar to the json Of bson Format , Therefore, more complex data types can be stored .

and Redis Compare ：
Redis For big data storage, there is no MongoDB major ,Redis It is used for fast reading and writing , therefore Redis Generally used as cache . For storage with large amount of data MongoDB. and MongoDB Low use value . comparison MySql, The cost of building a data server is high .
What situation to use MongoDB：
Large amount of data , Write operations are frequent , Lower value .
Large amount of data , therefore Redis Eliminate .（ comparison Redis Reading and writing performance is definitely not comparable ）
If you use MySql, Then the cost of building a data server is high , But storing data with low value , Don't bargain . So choose MongoDB.

MongoDB characteristic

Mongo The biggest feature is that it supports a very powerful query language , Its syntax is somewhat similar to that of an object-oriented query language , You can almost implement most of the functionality of a relational database single table query , It also supports indexing data .
It is characterized by high performance 、 Easy to deploy 、 Easy to use , It's very convenient to store data . The main features are ：

1. For collection storage , Easy to store data of object type .
2. Model freedom .
3. Support dynamic query .
4. Support full indexing , Contains internal objects .
5. Support query .
6. Support for replication and recovery .
7. Use efficient binary data storage , Include large objects （ Video, etc ）.
8. Automatic processing of debris , To support the scalability of the cloud computing hierarchy .
9. Support RUBY,PYTHON,JAVA,C++,PHP,C# multilingual .
10. The file storage format is BSON（ A kind of JSON An extension of ）.

MongoDB Architecture

MongoDB The logical structure of is a hierarchical structure . Mainly by ： file (document)、 aggregate (collection)、 database (database) These three parts make up . The logical structure is user oriented , The user to use MongoDB It's the logical structure that's used to develop an application .

1. MongoDB Documents （document）, Equivalent to a row of records in a relational database .
2. Multiple documents make up a collection （collection）, The equivalent of a relational database table .
3. Multiple sets （collection）, Logically organized , Database （database）.
4. One MongoDB Instance supports multiple databases （database）.
   

MongoDB data type

data type	describe
String	character string . Data types commonly used to store data . stay MongoDB in ,UTF-8 The encoded string is legal .
Integer	Integer values . For storing values . Depending on which server you use , Can be divided into 32 Bit or 64 position .
Boolean	Boolean value . Used to store Boolean values （ really / false ）.
Double	Double precision floating point value . Used to store floating point values .
Array	Used to store an array or list or values as a key .
Timestamp	Time stamp . Record when the document was modified or added .
Object	Used for embedded documents .
Null	Used to create a null value .
Date	Date time . use UNIX Time format to store the current date or time . You can specify your own time and date ： establish Date object , Incoming year, month and day information .
Object ID	object ID. For creating documents ID.
Binary Data	binary data . Used to store binary data .
Code	Code type . Used for storage in documents JavaScript Code .
Regular expression	Regular expression type . Used to store regular expressions .

Special instructions ：
1、ObjectID There must be , If we set it, use ours , We didn't set up ,MongoDB Just help us generate a .
ObjectID Class is similar to a unique primary key , It can be quickly generated and sorted , contain 12bytes, The meaning is

• The first four bytes identify the creation unix Time stamp , GMT UTC Time , It's later than Beijing time 8 Hours .
• Next 3 Bytes is the machine identity code , Distinguish between different devices
• The next two bytes are determined by the process id form PID( process id)
• The last three bytes are random Numbers

MongoDB Must have one of the documents stored in _id key . The value of this key can be of any type , The default is one ObjectId object

2、 Time stamp
BSON There is a special timestamp type , Not related to ordinary date types .
The timestamp value is one 64 The value of a . among ：
front 32 A is a time_t value 【 And Unix A new era （1970 year 1 month 1 Japan ） The number of seconds apart 】
after 32 Bit is an increasing ordinal number that operates in a given second
In a single mongod In the example , The timestamp value is usually unique .

3、 date
Represents the current distance Unix A new era （1970 year 1 month 1 Japan ） Millisecond count . Date types are signed , negative
Express 1970 Year before date .

Window edition MongoDB install

Direct double click msi Start setup , Can be installed .
After installation ：

mongo.exe The client side. , Used to connect the service
mongod.exe It is used to start the service
Start the service ： First of all, we need a folder for storing data . Default port number 27017

Specify the port to start , Add... After the command -port 8989

Start the client to connect ： The default is to connect to the local 27017 port

Specify the port connection ： mongo 127.0.0.1:8989

Docker In the environment MongoDB install

In the production environment, we will The server is deployed in Linux in , Only need window Just connect in
stay Linux Create a virtual machine mongo Containers , The order is as follows ：

docker run ‐id ‐‐name mongo ‐p 27017:27017 mongo

stay Window Command line window access login command ：
mongo 192.168.200.128 Port number not written default 27017