Connect to MySQL via PyMySQL

Install PyMySQL

Click the start button -- run -- enter 'cmd' -- enter the command 'pip install PyMySQL' to automatically download and install
```
	
pip install PyMySQL
```

Python connects to MySQL, first import the pymysql package

```
import pymysql
```

Open MySQL connection host address (host) port number (port) database name (db) user name (user) password (password) character set encoding (chareset)

db=pymysql.connect(host='127.0.0.1',
                   port=3306,
                   db='python3',
                   user='root',
                   password='123456',
                   charset='utf8')

Database query operation

Python queries MYSQL to use the fetchone() method to obtain a single piece of data, and use the fetchall() method to obtain multiple pieces of data
fetchone(sql): This method gets the next query result set, the result set is an object
fetchall(): accepts all returned result rows
rowcount(): This is a read-only property and returns the number of rows affected after executing the execute() method

Enter the sql statement to query all the data in the database
```
sql='SELECT * FROM student'
```
Use the cursor() method to get the operation cursor
```
cur=db.cursor()
```
Send command and return result, stored in cursor
```
cur.execute(sql)
```
fetchall() accepts all returned result rows

rows=cur.fetchall()
for r in rows:
    print('Student ID:{0}Telephone:{1}Name:{2}Gender:{3}'.format(r[0],r[1],r[2],r[3]))
print('Reading finished')

Example: Create a registration page

#Import the pymysql package
import pymysql

#Open MySQL connection
db=pymysql.connect(host='127.0.0.1',
                   port=3306,db='python3',
                   user='root',
                   password='123456',
                   charset='utf8')

#User input input()
studentNo=input('Please enter the student number:')

#Check if the student number exists
sql='''
    SELECT studentName FROM python3.student WHERE studentNo={0}
'''.format(studentNo)

#Use the cursor() method to get the operation cursor
cursor=db.cursor()

#Send the command and return the result, stored in the cursor
cursor.execute(sql)

#Get the next query result set, the result set is an object
one_row=cursor.fetchone()

# Determine if the student number exists
if one_row is not None:
    print('Student ID already exists, please re-enter...')
else:
    studentName=input('Please enter your name:')
    loginpwd= input('Please enter your password:')
    sex= input('Please enter gender:')
    insert_sql='''
        INSERT INTO python3.student
            (studentNo,loginPwd,studentName,sex
           )
        VALUES (
                '{0}',
                '{1}',
                '{2}',
                '{3}'
                );
    '''.format(studentNo,loginpwd,studentName,sex)
    try:
        cursor.execute(insert_sql)
        db.commit()
        print('Added successfully...')
    except:
        print('Add failed...')

Connect to MySQL via PyMySQL

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