python 操作mysql

import mysql.connector

class mydb():
    def __init__(self):
        self.connection =  mysql.connector.connect(
          host="localhost",       # 数据库主机地址
          user="root",    # 数据库用户名
          passwd="root",   # 数据库密码
          database="runoob_db",
        )
        self.cursor = self.connection.cursor()
        self.db = 'runoob_db'
    def createDB(self):
        #判断数据库是否存在#
        sql = "SHOW DATABASES"
        self.cursor.execute(sql)
        if self.cursor:
            for db in self.cursor:
                if db[0] == self.db:
                    hasDB=True
                    break
                else:
                    hasDB=False
            if hasDB == False:
                sql = "CREATE DATABASE runoob_db"
                self.cursor.execute(sql)
    def showDB(self):
        sql = "SHOW DATABASES"
        self.cursor.execute(sql)
        return self.cursor
    def createTable(self):
        sql="CREATE TABLE sites (name varchar(100),url varchar(200))"
        self.cursor.execute(sql)
    def innsertData(self):
        sql = "INSERT INTO sites (name, url) VALUES (%s, %s)"
        val = ("RUNOOB", "https://www.runoob.com")
        self.cursor.execute(sql, val)
        self.connection.commit()
        return self.cursor.rowcount
    def innsertDates(self):
        sql ="INSERT INTO sites (name, url) VALUE (%s, %s)"
        val = [
            ('Google', 'https://www.google.com'),
            ('Github', 'https://www.github.com'),
            ('Taobao', 'https://www.taobao.com'),
            ('stackoverflow', 'https://www.stackoverflow.com/')
        ]
        self.cursor.executemany(sql, val)
        self.connection.commit()
        return self.cursor.rowcount
    def queryData(self, columns = "*", where="1=1"):
        sql = "SELECT " + columns +" FROM sites" + " WHERE " + where
        self.cursor.execute(sql)
        data = self.cursor.fetchall()
        return data
    def deleteData(self, whereItems):
        sql = "DELETE FROM sites WHERE "
        if whereItems:
            for key, value in whereItems.items():
                sql += key + "='" + value + "'"
        self.cursor.execute(sql)
        self.connection.commit()
        return self.cursor.rowcount


db = mydb()

"""打印所有数据库"""
"""
databases = db.showDB()
if databases:
    for x in databases:
        print(x)
"""
"""添加单条数据"""
#db.innsertData()

"""批量添加数据"""
#db.innsertDates();

"""批量查询数据"""
nums = db.queryData('url')
if nums:
    for x in nums:
        print(x)
""""条件查询"""
#nums = db.queryData('url', 'name="Google"')
#print(nums)

"""条件删除"""
#where = {'name': 'Google'}
#db.deleteData(where)