python与mysql数据库交互的实现

import pymysql 
db = pymysql.connect(host='localhost',user='root',password='123456',port=3306,db='spiders',charset=' utf8')

# 导包
import pymysql 
# 使用pymysql连接上mysql数据库服务器，创建了一个数据库对象；
db = pymysql.connect(host='localhost',user='root', password='123456',
     port=3306, db='huangwei', charset='utf8')
# 开启mysql的游标功能，创建一个游标对象；    
cursor = db.cursor()
# 要执行的SQL语句；
sql = "select * from student"
# 使用游标对象执行SQL语句；
cursor.execute(sql)
# 使用fetchone()方法，获取返回的结果，但是需要用变量保存返回结果；
data = cursor.fetchone()
print(data)
# 断开数据库的连接，释放资源；
db.close()

import pymysql 
db = pymysql.connect(host='localhost',user='root', password='123456',port=3306, db='huangwei', charset='utf8')

# 创建一个游标对象；
cursor = db.cursor()
 
# 建表语句；
sql = """
  create table person(
   id int auto_increment primary key not null,
   name varchar(10) not null,
   age int not null
  )charset=utf8
  """

# 执行sql语句；
cursor.execute(sql)
 
# 断开数据库的连接；
db.close()

import pymysql
 
db = pymysql.connect(host='localhost',user='root',db='huangwei',password='123456',port=3306,charset='utf8')
      
cursor = db.cursor()

cursor.execute('select count(*) from person')
aa = cursor.fetchone()
print(aa)
cursor.execute('select name,age from person') 
for i in range(aa[0]):
 a,b = cursor.fetchone()
 c = "我的名字叫{}，今年{}岁".format(a,b)
 display(c)
db.close()

import pymysql
 
db = pymysql.connect(host='localhost',user='root',db='huangwei',password='123456',port=3306,charset='utf8')
      
cursor = db.cursor()

cursor.execute('select name,age from person')
aa = cursor.fetchall()
# print(aa)
for a,b in aa:
 c = "我的名字叫{}，今年{}岁".format(a,b)
 display(c)
db.close()

import pymysql 
import pandas as pd

db = pymysql.connect(host='localhost',user='root',db='huangwei',password='123456',port=3306,charset='utf8')
cursor = db.cursor()

df1 = pd.read_sql("select * from student where ssex='男'",db)
display(df1)

df2 = pd.read_sql("select * from student where ssex='女'",db)
display(df2)

import pymysql

db = pymysql.connect(host='localhost',user='root', password='123456',port=3306, db='huangwei', charset='utf8')
 
cursor = db.cursor()
 
# mysql中SQL语句怎么写，这里就怎么写；
name = "猪八戒"
age = 8000
sql = 'insert into person(name,age) values ("猪八戒",8000)'

try:
 cursor.execute(sql)
 db.commit()
 print("插入成功")
except:
 print("插入失败")
 db.rollback()
db.close()

import pymysql
 
db = pymysql.connect(host='localhost',user='root', password='123456',port=3306, db='huangwei', charset='utf8')
 
cursor = db.cursor()
 
# 插入数据
sql = 'insert into person(name,age) values(%s,%s)'
try:
 cursor.execute(sql,('孙悟空',100000))
 db.commit()
 print("插入成功")
except:
 print("插入失败")
 db.rollback()
db.close()

import pymysql
 
db = pymysql.connect(host='localhost',user='root', password='123456',port=3306, db='huangwei', charset='utf8')
 
cursor = db.cursor()
 
# 插入数据
sql = 'insert into person(name,age) values(%s,%s)'
# 注意：(('牛魔王',9000),('铁扇公主',8000),('玉皇大帝',6000))也可以，小括号都可以换为中括号
datas = [('牛魔王',9000),('铁扇公主',8000),('玉皇大帝',6000)]
try:
 cursor.executemany(sql,datas)
 db.commit()
 print("插入成功")
except:
 print("插入失败")
 db.rollback()
db.close()

import pymysql
 
db = pymysql.connect(host='localhost',user='root', password='123456',port=3306, db='huangwei', charset='utf8')
 
cursor = db.cursor()
 
# 更新数据
sql = 'update person set age=%s where name=%s'
try:
 cursor.execute(sql,[90000,"玉皇大帝"])
 db.commit()
 print("更新成功")
except:
 print("更新失败")
 db.rollback()
db.close()

import pymysql
 
db = pymysql.connect(host='localhost',user='root', password='123456',port=3306, db='huangwei', charset='utf8')
 
cursor = db.cursor()
 
# 删除数据
sql = 'delete from person where age=8000'
try:
 cursor.execute(sql)
 db.commit()
 print("删除成功")
except:
 print("删除失败")
 db.rollback()
db.close()