python操作mysql实例 Python3.6简单的操作Mysql数据库的三个实例

import pymysql
# 创建连接
# 参数依次对应服务器地址，用户名，密码，数据库
conn = pymysql.connect(host='127.0.0.1', user='root', passwd='123456', db='demo')
# 创建游标
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
# 执行语句返回影响的行数
effect_row = cursor.execute("select * from course")
print(effect_row)
# 获取所有数据
result = cursor.fetchall()
result = cursor.fetchone() # 获取下一个数据
result = cursor.fetchone() # 获取下一个数据（在上一个的基础之上）
# cursor.scroll(-1, mode='relative') # 相对位置移动
# cursor.scroll(0,mode='absolute') # 绝对位置移动
# 提交，不然无法保存新建或者修改的数据
conn.commit()
# 关闭游标
cursor.close()
# 关闭连接
conn.close()

import pymysql
# 建立连接
conn = pymysql.connect(host='127.0.0.1', user='root', passwd='123456', db='demo')
# 创建游标
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)
# 插入一条数据 %s是占位符 占位符之间用逗号隔开
effect_row = cursor.execute("insert into course(cou_name,time) values(%s,%s)", ("Engilsh", 100))
print(effect_row)
conn.commit()
cursor.close()
conn.close()

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()