【实验】MySQL多少数据需要建立索引

数据准备

采用Python随机生成若干条数据，以备测试使用，代码如下

# db.py
import pymysql
# 默认数据返回的是二维列表：
# (
#     (每一行)
#     (每一行)
# )

# 加上 cursor=pymysql.cursors.DictCursor后的数据返回格式：
# [{'psw': 'e10adc3949ba59abbe56e057f20f883e'}]

class db:
    host = ""
    port = 3306
    user = "root"
    psw = ""
    db_name = "testdb"
    connect = None
    cursor = None
    def __init__(self):
        self.connect = pymysql.connect(host=self.host,port=self.port,user=self.user,passwd=self.psw,db=self.db_name)
        self.cursor = self.connect.cursor(cursor=pymysql.cursors.DictCursor)
        pass

    def query(self,sql):
        connect = pymysql.connect(host=self.host,port=self.port,user=self.user,passwd=self.psw,db=self.db_name)
        cursor = connect.cursor(cursor=pymysql.cursors.DictCursor)
        cursor.execute(sql)
        data = cursor.fetchall()
        connect.close()
        return data

    def operate(self,sql):
        # connect = pymysql.connect(host=self.host,port=self.port,user=self.user,passwd=self.psw,db=self.db_name)
        # cursor = connect.cursor(cursor=pymysql.cursors.DictCursor)
        try:
            self.cursor.execute(sql)
            self.connect.commit()
            self.count = self.cursor.rowcount
            return count
        except Exception as e:
            print(e)
            print(sql)
            return False

import db as db
import random

my_db = db.db()

def get_vcode():
    v_code = chr(random.randint(65,90))
    v_code = v_code + chr(random.randint(97,122))
    v_code = v_code + chr(random.randint(65,90))
    v_code = v_code + chr(random.randint(48,57))
    v_code = v_code + chr(random.randint(65,90))
    v_code = v_code + chr(random.randint(48,57))
    return v_code

if __name__ == '__main__':
    for i in range(1,1000000):
        sql = "INSERT INTO `testdb`.`test_data_100w`(`data_1`, `data_2`, `data_3`) VALUES (%d, '%s', '%s')" % (i+1,get_vcode(),get_vcode())
        my_db.operate(sql)
        print("当前编号："+str(i))