Database foundation and installation

1、 Database foundation

What is data

Symbolic description of objective affairs
Data is the carrier of information

data classification

Text
graphics
voice
Images

database structure

Database software
A database software , There can be many libraries .
library
DataBase, abbreviation ：DB
A library can have many tables .
surface
Table
A table can store many result sets .
Result set
record
Result set refers to ： A collection of data

database model

Hierarchical
Reticular type
Relational type
…

Common relational databases

MySql
Open source 、 free .
The original company ： Swedish AB company .
Current company ：oracle
It is a small and medium-sized database
Oracle
company ：oracle
Paid Products .
But the function is free .
Medium and large databases
SqlServer
company ： Microsoft
Medium and large databases
DB2
company ：IBM
Large data

2、MySql database

Download version

zip edition
Green version , When the download is complete , In order to zip The formation of compressed packets reflects .
Decompress package , Database ( Be careful ： There is no setup , Unzip to use ).
Be careful ：zip Usually in cmd Used in , therefore , Environment variables need to be configured ( And configuration jdk similar )
msi edition ( Use )
Installed version , After downloading successfully , Use .msi Program to install .
After installation , You can use it directly . No configuration is required
Download from the official website
https://www.oracle.com/index.html
Download location

3、MySql Database installation

4、MySql Visualization software installation

You can use software , Operate data in a graphical interface .
MySql There are many products of video software , We use Navicat

5、MySql Basic commands

mysql command
Important orders .
Connect MySql database

 Format : 
mysql [-h Server address ] -u Account name  -p password 

Command parameter parsing
h： Server address . LAN ：192.168.xxx.xxx. Wide area network ： static state IP. Be careful ： If it is this machine, it does not need to be used -h
-u： Database account .
-p： Database password
Be careful ： By default , stay cmd Use in MySql command , It's invalid . Need to put MySql Install under directory bin Add directory address to environment variable path Then you can .
Be careful ： By default ,root Accounts cannot be accessed remotely . because root The permission field of the account in the user table is ：
localhost( Local ), therefore , It's not remotely accessible . If there is a need for remote access , Use update The command is used in the user table
root In the field localhost by “ ”. then , Remote access can be realized .
take sql File import database
Put a local sql The file is imported into the database .
Database files are usually , With the extension ：.sql

 Format : 
mysql -u account  -p password   Database name  <  Database files .sql

mysqladmin command
Database management commands
You can use this command to change the account password .

 Format : 
mysqladmin -u account  -p Old password  password " New password "

mysqldupm command
Save the database as sql file

 Format : 
mysqldump -u account  -p password   Database name  > d:/sql File name .sql

mysql Other commands
show databases： check mysql All the library names in the database .
use Database name ： Enter the database with the specified name
show tables： View all data table names in the specified database .
desc Data table name ： View the structure of the specified data table .
show create table Data table name ： View the source code of the creation of the specified data table
\s： View the server information .
\c： Terminate current sql command
\h： Similar to help file , You can see sql Appoint .
\q： sign out mysql