1.pymysql main method

pymysql.connect() parameter description: (parameters that need to be added when connecting to the database)
host(str): MySQL server address
port(int): MySQL server port number
user(str): username
passwd(str): password
db(str): database name
charset(str): connection code
The methods supported by the connect() object:
cursor() uses the connection to create and return the cursor
commit() commit the current transaction
rollback() roll back the current transaction
close() close the connection
Methods supported by the cursor object:
execute(op) Execute a database query command
fetchone() Get the next row of the result set
fetchmany(size) Get the next few rows of the result set
fetchall() Get all rows in the result set
rowcount() returns the number of data or the number of affected rows
close() close the cursor object

2. Common operation explanation

Ready to work:

1. Import the library

import pymysql

2. Connect to the database

db = pymysql.connect(
				    host='localhost',
				    port=3306,
				    user='root',
				    password='123456',
				    database='【数据库名】',
				    charset='utf8'
    				) #mysql参数填自己配置的

3. Create a cursor

cursor = db.cursor()

Commonly used SQL statements

Insert data

method one:

sql = 'insert into 【表名】(【参数1】,【参数2】,【参数3】...) values(%s, %s, %s, %s...)'  # 注意是%s,不是s%

Way two:

sql = 'insert into 【表名】(【参数1】,【参数2】,【参数3】...) %（【数据1】,【数据2】,【数据3】...）'

delete data

sql = 'delete from 【表名】 where 【查询参数】= %s'%(【数据】)

change the data

sql = 'update 【表名】 set 【参数】 = "%s" where 【查询参数】 = "%s"'%(【数值】,【数值】)

Query data

sql = 'select 【参数】 from 【表名】 where 【查询参数】= %s '%(【数据】)

Execute sql statement (can execute sql in a loop)

Parameter note: If the data to be executed contains quotation marks, use method two, because the sql statement itself is a string, and the quotation marks of multiple strings lead to confusion in the sql statement

Method one (corresponding to method one of inserting data):

cursor.execute(sql,([数据1],[数据2],))#注意元组最后有一个逗号

Method one (corresponding to method two of inserting data):

cursor.execute(sql)

Note: If you need to execute the function of the database itself, you only need to replace the data with a database function:
such as:now()

Close cursor

cursor.close()

Close the database (all operations are complete, close the database)

db.close()

Note: If you frequently connect to the database to prevent disconnection, you can use:db.ping(reconnect=True)

Summary of pymysql common methods

python-pymysql