python往mysql数据库中写入数据和更新插入数据

1. 连接mysql

import pymysql
db = pymysql.connect(host=‘localhost‘,user=‘root‘,password=‘123456‘,port=3306,db=‘spiders‘)
cursor = db.cursor()
sql = ‘select * from students;‘
cursor.execute(sql)
cursor.close()
db.close()

2. 多字段动态插入mysql数据库中

import pymysql
db = pymysql.connect(host=‘localhost‘,db=‘spiders‘)
data = {
    ‘id‘: ‘20180606‘,‘name‘: ‘Lily‘,‘age‘: 20
}
table = ‘students‘
keys = ‘,‘.join(data.keys())
values = ‘,‘.join([‘%s‘] * len(data))
sql = ‘INSERT INTO {table}({keys}) VALUES ({values})‘.format(table=table,keys=keys,values=values)
try:
   cursor.execute(sql,tuple(data.values()))
   print(‘Successful‘)
   db.commit()
except:
   print(‘Failed‘)
   db.rollback()
cursor.close()
db.close()

3. 数据更新插入mysql数据库中

import pymysql
db = pymysql.connect(host=‘localhost‘,‘age‘: 25
}
table = ‘students‘
keys = ‘,‘.join([‘%s‘] * len(data))
sql = ‘INSERT INTO {table}({keys}) VALUES ({values}) ON DUPLICATE KEY UPDATE‘.format(table=table,values=values)
update = ‘,‘.join([" {key} = %s".format(key=key) for key in data])
sql += update
try:
   cursor.execute(sql,tuple(data.values())*2)
   print(‘Successful‘)
   db.commit()
except:
   print(‘Failed‘)
   db.rollback()
cursor.close()
db.close()