Mysql:sql overview and database system introduction | dark horse programmer

One 、 Programming Language Overview

programing language （programming language） It can be simply understood as a language that can be recognized by both computers and people .

• machine language

• assembly language

• High-level language

machine language

assembly language

High-level language

Two 、SQL Overview

• SQL Full name ： Structured Query Language, Structured query language , A standard computer language for accessing and processing databases .SQL Language 1974 Year by year Boyce and Chamberlin Put forward , And first of all in the IBM The relational database system developed by the company SystemR Implemented on . The National Bureau of standards (ANSI) Start working on SQL standard , And in 1986 year 10 The earliest... Was released in June SQL standard , The standard version of the extension is 1989 Published in SQL-89, And after 1992 Version formulated in SQL-92 and 1999 year ISO Released version SQL-99.
  SQL The standard has been revised and improved several times , It's more powerful , But at present, many database systems only support SQL-99 Part of the characteristics of , And most database systems can support 1992 Made in SQL-92.

SQL Characteristics

With comprehensive unity , Support of different databases SQL not quite the same
Non procedural language
The language is simple , Users are easy to accept
Provide two ways to use in one grammatical structure

SQL The composition of language

• Data definition language -DDL

• Data manipulation language -DML

• Data control language -DCL

• Data query language -DQL

SQL Language foundation

Grammatical features ：

• SQL Case insensitive to keywords

• SQL Statements can be written in one or more lines , End with branch SQL Notes ：

  

3、 ... and 、 Introduction to database system

1、 database

database （DB） Is a collection of data stored on disk in some organized way .

2、 Database application

Database application system refers to the application software based on database .

3、 Classification of database management system

Relational database （RDBMS）
（1）Oracle database （ The eldest brother , The most profitable database ）
（2）MySQL database （ The most popular medium-sized database ））
（3）SQL server database （Windows The best database in the world ）
（4）PostgreSQL（ The most powerful open source database ）
（5）SQLite（ The most popular embedded database ）
Non relational database (NoSQL)
（1）Redis（ The best cache database ）
（2）MongoDB（ The best documented database ）
（3）Elasticsearch（ The best search service ）
（4）Cassandra（ The best columnar database ）
（5）HBase（ Excellent distributed 、 Columnar database ）

4、SQL Relationship with database management system

SQL Is a language used to operate a database ,SQL Applicable to all relational databases .
MySQL、Oracle、SQLServer Is a database software , These database software support standards SQL, That is, through SQL You can use these software , But every database system will be in the standard SQL Expand your own SQL grammar .
Most of NoSQL The database has its own operating language , Yes SQL The support is not good .

5、 Database management system （ Database software ）

Database management system （DBMS） Used to create and maintain databases . for example ,SQL Server、Oracle、MySQL And so on are database management systems . chart 1.1 Describes the database 、 The connection between database application system and database management system .

author ： Dark horse programmer official

Game programming , A game development favorite ~

If the picture is not displayed for a long time , Please use Chrome Kernel browser .