每日日报2021.11.3

完成内容：

1.python的学习 mysql数据库

1.建表

import mysql.connector

 mydb = mysql.connector.connect( host="localhost", user="root", passwd="123456", database="runoob_db" )

mycursor = mydb.cursor() mycursor.execute("CREATE TABLE sites (name VARCHAR(255), url VARCHAR(255))")

 2.查询表是否存在

import mysql.connector

mydb = mysql.connector.connect( host="localhost", user="root", passwd="123456", database="runoob_db" )

mycursor = mydb.cursor() mycursor.execute("SHOW TABLES") for x in mycursor: print(x)

3.主键设置

import mysql.connector

mydb = mysql.connector.connect( host="localhost", user="root", passwd="123456", database="runoob_db" )

mycursor = mydb.cursor() mycursor.execute("ALTER TABLE sites ADD COLUMN id INT AUTO_INCREMENT PRIMARY KEY")

4.方法2

import mysql.connector

mydb = mysql.connector.connect( host="localhost", user="root", passwd="123456", database="runoob_db" )

mycursor = mydb.cursor() mycursor.execute("CREATE TABLE sites (id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(255), url VARCHAR(255))")

遇到问题：
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目标：继续学习