Python使用Pandas库实现MySQL数据库的读写

pd.io.sql.to_sql(df1,tablename,con=conn,if_exists='repalce') 　

import pandas as pd
from sqlalchemy import create_engine
# 初始化数据库连接，使用pymysql模块
# MySQL的用户：root, 密码:147369, 端口：3306,数据库：test
engine = create_engine('mysql+pymysql://root:123456@localhost:3306/test')
# 查询语句，选出employee表中的所有数据
sql = ''' select * from employee; '''
# read_sql_query的两个参数: sql语句， 数据库连接
df = pd.read_sql_query(sql, engine)
# 输出employee表的查询结果
print(df)

# 新建pandas中的DataFrame, 只有id,num两列
df = pd.DataFrame({'id': [1, 2, 3, 4], 'name': ['zhangsan', 'lisi', 'wangwu', 'zhuliu']})
# 将新建的DataFrame储存为MySQL中的数据表，储存index列
df.to_sql('mydf', engine, index=True)
print('Read from and write to Mysql table successfully!')

# -*- coding: utf-8 -*-

# 导入必要模块
import pandas as pd
from sqlalchemy import create_engine

# 初始化数据库连接，使用pymysql模块
db_info = {'user': 'root',
      'password': '123456',
      'host': 'localhost',
      'port': 3306,
      'database': 'test'
      }

engine = create_engine('mysql+pymysql://%(user)s:%(password)s@%(host)s:%(port)d/%(database)s?charset=utf8' % db_info, encoding='utf-8')
# 直接使用下一种形式也可以
# engine = create_engine('mysql+pymysql://root:123456@localhost:3306/test')

# 读取本地CSV文件
df = pd.read_csv("C:/Users/fuqia/Desktop/example.csv", sep=',')
print(df)
# 将新建的DataFrame储存为MySQL中的数据表，不储存index列(index=False)
# if_exists:
# 1.fail:如果表存在，啥也不做
# 2.replace:如果表存在，删了表，再建立一个新表，把数据插入
# 3.append:如果表存在，把数据插入，如果表不存在创建一个表！！
pd.io.sql.to_sql(df, 'example', con=engine, index=False, if_exists='replace')
# df.to_sql('example', con=engine, if_exists='replace')这种形式也可以
print("Write to MySQL successfully!")

from sqlalchemy import create_engine 
 
 engine = create_engine('mysql+pymysql://root:123456@localhost:3306/test')
sql = "DROP TABLE IF EXISTS example"
engine.execute(sql)

import pymysql
from sqlalchemy import create_engine

conn = pymysql.connect(host='127.0.0.1', port=3306, user='root', passwd='123456', db='test')
# engine = create_engine('mysql+pymysql://root:123456@localhost:3306/test')
sql = "DROP TABLE IF EXISTS test_input"
cursor = conn.cursor()
cursor.execute(sql)