大家早上好啊，今天我們繼續(xù)學(xué)習(xí)python操作MySQL（增刪改查）。

大數(shù)據(jù)機(jī)器學(xué)習(xí)數(shù)據(jù)分析爬蟲Python開發(fā)愛好者，?MySQL 是我們經(jīng)常接觸的數(shù)據(jù)庫，它的優(yōu)點(diǎn)好處我就不說了，（其實(shí)本人也說不出什么，反正是常用的數(shù)據(jù)庫）那么我們?nèi)绾问褂胮ython 對mysql數(shù)據(jù)庫進(jìn)行操作呢。下面我來給大家說說。

首先連接mysql

在建立連接前我們的python 要安裝pymsql

pip install pymysql

在命令行里輸入 pip install pymysql

下面打開我們的IDE 我使用的是pycharm

# !/usr/bin/env python

# -*- coding:utf-8 -*-

'''

1.0 python連接mysql 并進(jìn)行增刪改查

'''

import pymysql.cursors

'''

連接數(shù)據(jù)庫

'''

#使用pymysql指令連接數(shù)據(jù)庫

connection = pymysql.connect(host = '127.0.0.1', #要連接的數(shù)據(jù)庫的IP地址

user = 'root', #登錄的賬戶名，如果登錄的是最高權(quán)限賬戶則為root

password = '123456', #對應(yīng)的密碼

db = 'iris', #要連接的數(shù)據(jù)庫

charset = 'utf8mb4', #設(shè)置編碼格式

#返回到Python的結(jié)果，以什么方式存儲，如Dict.Cursor是以字典的方式存儲

#如果不加這行數(shù)據(jù)是以元組方式返回

cursorclass = pymysql.cursors.DictCursor

)

這樣我們就建立了python 同mysql 的連接

創(chuàng)建表

try:

'''

創(chuàng)建表

'''

# 使用cursor()方法獲取操作游標(biāo)

with connection.cursor() as cursor:

# 如果數(shù)據(jù)表已經(jīng)存在使用 execute() 方法刪除表。

cursor.execute("drop table if EXISTS users")

sql = '''create table users (

id int(11) not null auto_increment,

email varchar(255) collate utf8_bin not null,

password varchar(255) collate utf8_bin not null,

primary key (id)

)

engine = InnoDB default charset=utf8 collate=utf8_bin

auto_increment=1;

'''

cursor.execute(sql)

except:

# 發(fā)生錯誤時(shí)回滾

connection.rollback()

finally:

# 關(guān)閉連接

connection.close()

插入數(shù)據(jù)

# 從數(shù)據(jù)庫鏈接中得到cursor的數(shù)據(jù)結(jié)構(gòu)

with connection.cursor() as cursor:

sql = " insert into users(email, password) VALUES (%s, %s)"

cursor.execute(sql,('webmaster@python.org','very_secret'))

# 執(zhí)行到這一行指令時(shí)才是真正改變了數(shù)據(jù)庫，之前只是緩存在內(nèi)存中

connection.commit()

批量插入數(shù)據(jù)

'''

批量插入數(shù)據(jù)

'''

#讀取文件

with open('iris.csv', 'r', encoding='utf-8', newline='') as f:

i = 0 #用來記錄讀取文件中數(shù)據(jù)的的次數(shù)

z = 0 #用來記錄讀取文件中數(shù)據(jù)的的次數(shù)

list = []

for line in f:

strs = line.split(',')

data = (strs[0], strs[1], strs[2], strs[3], strs[4].replace(" ","")) #數(shù)據(jù)的最后一行會有一個(gè) 換行符，用replace替換掉

list.append(data)

i += 1

z += 1

if i >= 10: #用于現(xiàn)在一次插入多少條這里是10條插入一次

with connection.cursor() as cursor:

sql = "insert into iris(sepal_length, sepal_width, petal_length, petal_width, uspecies) "

"VALUES (%s, %s, %s, %s, %s)"

cursor.executemany(sql, list) #批量添加數(shù)據(jù)時(shí) 要用executemany

connection.commit()

print("插入{}條數(shù)據(jù),已插入{}條數(shù)據(jù)".format(i, z))

i = 0 #對計(jì)數(shù)歸零

list.clear() #清理數(shù)據(jù)列表

if i > 0 : # 循環(huán)文件完畢后，對剩余的數(shù)據(jù)進(jìn)行插入，（例如小于10的剩余數(shù)據(jù)，比如你的文件有55行，剩余的5行就要這樣插入）

cursor.executemany(sql, list)

connection.commit()

查詢數(shù)據(jù)

'''

查詢數(shù)據(jù)

'''

#單一數(shù)據(jù)

with connection.cursor() as cursor:

sql = " select id, email, password from users where email = %s"

cursor.execute(sql,('sfs1100@126.com'))

result = cursor.fetchone() #fetchone()只取出第一條結(jié)果

print(result)

print(type(result))

#多條數(shù)據(jù)

with connection.cursor() as cursor:

sql = " select * from iris where sepal_length > %s"

cursor.execute(sql, (3))

result = cursor.fetchall() #fetchone()取出查詢后的所有數(shù)據(jù)

print(result)

print(type(result))

for each in result:

print(each['uspecies'])

更新數(shù)據(jù)

'''

更新數(shù)據(jù)

'''

with connection.cursor() as cursor:

sql = " update users set email = %s where password = %s"

cursor.execute(sql, ('sfs1100@126.com', 'very_secret'))

connection.commit()

刪除數(shù)據(jù)

'''

刪除數(shù)據(jù)

'''

with connection.cursor() as cursor:

sql = "delete from users where email = %s"

cursor.execute(sql, ('sfs1100@126.com'))

connection.commit()