What is the database

The existence of a data warehouse

Why use a database

Before using Excel to manage data,

Excel shortcomings

Can not manage large amounts of data (10W magnitude data)
You can not operate concurrently with a data table
Data do not support advanced operations, such as: grouping, even tables, etc.

Classification database

Relational database
to the data type of each column will be constrained, id (int), name (string type)
maridb, MySQL ----- (with more, free)
SqlServer ----- (Microsoft, universities, government)
the Oracle ----- (Ali)
SQLite
Non-relational databases

There is no constraint on the data type of each column, it may be any type of data
```
 memcache
 mongodb
 redis    ------（微博）
```
The biggest difference:
relational database, the presence of hard disk data
non-relational database, the data stored in memory

Architecture database

Similar to the client and the server socket

Process:

mysql server first starts, listens in a particular port (3306)
mysql client server connection
mysql client can send the relevant operation command to operate the data stored in the server

Basic instructions database

Common parameters

-u: User username : password Password : host name or host MySQL-uroot--p -h 192.168.1.10 ip : Port default is 3306 mysql -uroot -p -h 192.168.1.10 -P 3307 common parameters:
-p
-h
-P

The basic operation of the database command

1）查看已有数据库
mysql>：show databases;

2）选择某个数据库
mysql>：use 数据库名

3）查看当前所在数据库
mysql>：select database();

4）创建数据库
mysql>：create database 数据库名 [charset=编码格式];
eg>: create database owen;
eg>: create database zero charset=utf8;
eg>: create database tank;

5）查看创建数据库的详细内容
mysql>：show create database 数据库名;
eg>: show create database owen;

6）删除数据库
mysql>: drop database 数据库名;
eg>: drop database tank;

Database naming convention:
1. contain letters, numbers, underscores, @, #, $
2 is case sensitive
3. Uniqueness
4. Keywords can not be used as SELECT Create
5. The number alone can not be used
6. up to 128

1028 Class Summary