Python 3.6 Simple operation of three instances of the Mysql database

Install pymysql

Reference: https: / / github com/PyMySQL/PyMySQL /

pip install pymsql

Example 1

import pymysql
#  Create a connection 
#  The parameters correspond in turn to the server address, username, password, and database 
conn = pymysql.connect(host='127.0.0.1', user='root', passwd='123456', db='demo')
#  Create a cursor 
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
#  Execution statement returns the number of affected rows 
effect_row = cursor.execute("select * from course")
print(effect_row)
#  Get all the data 
result = cursor.fetchall()
result = cursor.fetchone() #  To obtain the 1 A data 
result = cursor.fetchone() #  To obtain the 1 Three data points (on 1 On the basis of) 
# cursor.scroll(-1, mode='relative') #  Relative position shift 
# cursor.scroll(0,mode='absolute') #  Absolute position shift 
#  Commit, otherwise the newly created or modified data cannot be saved 
conn.commit()
#  Close the cursor 
cursor.close()
#  Close the connection 
conn.close()

Example 2

import pymysql
#  Establish a connection 
conn = pymysql.connect(host='127.0.0.1', user='root', passwd='123456', db='demo')
#  Create a cursor 
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
#  insert 1 The data  %s Is a placeholder   Placeholders are separated by commas 
effect_row = cursor.execute("insert into course(cou_name,time) values(%s,%s)", ("Engilsh", 100))
print(effect_row)
conn.commit()
cursor.close()
conn.close()

Example 3

import pymysql.cursors
# Connect to the database
connection = pymysql.connect(host='localhost',
        user='user',
        password='passwd',
        db='db',
        charset='utf8mb4',
        cursorclass=pymysql.cursors.DictCursor)
try:
 with connection.cursor() as cursor:
  # Create a new record
  sql = "INSERT INTO `users` (`email`, `password`) VALUES (%s, %s)"
  cursor.execute(sql, ('webmaster@python.org', 'very-secret'))
 # connection is not autocommit by default. So you must commit to save
 # your changes.
 connection.commit()
 with connection.cursor() as cursor:
  # Read a single record
  sql = "SELECT `id`, `password` FROM `users` WHERE `email`=%s"
  cursor.execute(sql, ('webmaster@python.org',))
  result = cursor.fetchone()
  print(result)
finally:
 connection.close()

conclusion