Python连接MySQL及一系列相关操作

一、首先需要安装包`pymysql`(python3所对应)

我使用的是Anaconda全家桶，打开cmd，进入Anaconda下的Scripts文件夹下输入命令：pip install pymysql进行下载安装
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二、我使用的编译器为Anaconda所带的`Jupyter Notebook`

1，在mysql中创建一个名称为`drop`的数据库，当然里面不存在表

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2，导包和配置数据库信息

import pymysql
DBHOST = 'localhost'
DBUSER = 'root'
DBPASS = 'beyond'
DBNAME = 'drop'
DBSET = 'utf8'

三、在drop数据库中创建water表

try:conn = pymysql.connect(host = DBHOST,user = DBUSER,password= DBPASS,database= DBNAME,charset= DBSET)#连接drop这个数据库print('seccessfull!!!')cur = conn.cursor()cur.execute("DROP TABLE IF EXISTS water")#创建water表之前先检查是否存在这个表，若存在则删除sql = "CREATE TABLE water(id int primary key NOT NULL AUTO_INCREMENT, circum varchar(8), area varchar(8), diameter varchar(8), PH varchar(8))"#创建表，其中id为主键、自增、不为空cur.execute(sql)print('create table seccess!!!')except pymysql.Error as e:print('table create is defeated!' + str(e))

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四、向water表中插入数据

try:conn = pymysql.connect(host = DBHOST,user = DBUSER,password= DBPASS,database= DBNAME,charset= DBSET)#连接drop这个数据库print('seccessfull!!!')cur = conn.cursor()sql = "INSERT INTO water(circum,area,diameter,PH) VALUE (%s,%s,%s,%s)"#向表中插入数据value = ('12.54','124.121','147.25',6)cur.execute(sql,value)conn.commit()print('insert seccess!!!')except pymysql.Error as e:print('insert is defeated!' + str(e))conn.rollback()conn.close()

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为了后续操作，这里多执行几次，多增加几组数据

五、查询water表中数据

try:conn = pymysql.connect(host = DBHOST,user = DBUSER,password= DBPASS,database= DBNAME,charset= DBSET)#连接drop这个数据库print('seccessfull!!!')cur = conn.cursor()sql = "SELECT * FROM water"#查询water表中数据信息cur.execute(sql)results = cur.fetchall()for row in results:#这里获取的results是个数组，里面分别存放每列的数值circum = row[1]area = row[2]diameter = row[3]ph = row[4]print('circum:%s,area:%s,diameter:%s,ph:%s'%(circum,area,diameter,ph))except pymysql.Error as e:print('query is defeat!' + str(e))conn.rollback()conn.close()

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六、更新water表中数据

try:conn = pymysql.connect(host = DBHOST,user = DBUSER,password= DBPASS,database= DBNAME,charset= DBSET)#连接python这个数据库print('seccessfull!!!')cur = conn.cursor()sql = "UPDATE water SET circum=%s,area=%s,diameter=%s WHERE ph=%s"#更新water表中数据信息value = ('15.5','15.5','15.5','6')#在ph=6的数据中，更改数据其他信息cur.execute(sql,value)conn.commit()print('update seccess!')except pymysql.Error as e:print('update is defeat!' + str(e))conn.rollback()conn.close()

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七、删除water表中指定位置数据

try:conn = pymysql.connect(host = DBHOST,user = DBUSER,password= DBPASS,database= DBNAME,charset= DBSET)#连接drop这个数据库print('seccessfull!!!')cur = conn.cursor()sql = "DELETE FROM water WHERE ph=%s"value = ('6')cur.execute(sql,value)#删除water表中ph=6的数据信息conn.commit()print('delete seccess!')except pymysql.Error as e:print('delete is defeat!' + str(e))conn.rollback()conn.close()

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八、删除water表

try:conn = pymysql.connect(host = DBHOST,user = DBUSER,password= DBPASS,database= DBNAME,charset= DBSET)#连接drop这个数据库print('seccessfull!!!')cur = conn.cursor()sql = "DROP TABLE IF EXISTS water"#删除water表cur.execute(sql)conn.commit()print('table delete is seccessful!')except pymysql.Error as e:print('table delete is defeat!' + str(e))conn.rollback()conn.close()