KwCheng's blog

char 以及varchar 都是用來儲存字元 , 字串的type , 

不同點在於 , char在儲存時是固定長度 , 而varchar則是可以變動長度來進行儲存(但不可大於我們所設的limit)

MySQL is a Relational SQL database management system , and it is open source software.

Relational database means that all the data is stored into different tables 

SQL stands for Structured Query Language , it is a database computer language 

designed for retrieval and management of data in relational database.

在database中 , 我們通常會需要設定一個key來做為每個紀錄的辨識 , 

而這樣的key , 我們就稱為Primary key.

First , we must connect to database by using root account.

# mysql -u root -p

修改Mysql的密碼 , 主要有以下兩個步驟 , 

1 . 連線Mysql

1. in  , 

example : select * from monday where category in('3')