Python3.8.3 操作MYSQL数据库

学习目标：

学习Python操作MYSQL数据库

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学习内容：

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1.python操作MYSQL数据库

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学习时间：

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2021-02-19

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学习笔记：

step1:安装python操作mysql数据库的库

 pip3 install PyMySQL

step2:示例代码

import pymysql
dbhost='localhost'
dbuser='root'
dbpass='root'
dbname='test'

try:
	db=pymysql.connect(host=dbhost,user=dbuser,password=dbpass,database=dbname)
	cursor = db.cursor()
	cursor.execute("SELECT VERSION()")
# 使用 fetchone() 方法获取一条数据
	data = cursor.fetchone()
	print("Database version : %s " % data)
except pymysql.Error as e:
	print("数据库连接失败："+str(e))

finally:
	if db:
		db.close()
		print('关闭数据库连接....')

在这里插入图片描述

step3:创建数据表

import pymysql
db = pymysql.connect(host='localhost',user='root',password='root',database='test')
cursor = db.cursor()
cursor.execute("DROP TABLE IF EXISTS EMPLOYEE")
sql = """CREATE TABLE EMPLOYEE (
			FIRST_NAME  CHAR(20) NOT NULL,
			LAST_NAME  CHAR(20),
			AGE INT,  
			SEX CHAR(1),
			INCOME FLOAT )"""

cursor.execute(sql)
# 关闭数据库连接
db.close()
print('创建数据表成功')

step4:插入数据

import pymysql
db = pymysql.connect(host='localhost',user='root',password='root',database='test')
cursor = db.cursor()
sql = "INSERT INTO EMPLOYEE(FIRST_NAME,LAST_NAME, AGE, SEX, INCOME) VALUES('Mac', 'Mohan', 20, 'M', 2000)"
try:
	cursor.execute(sql)
	db.commit()
	print('commit......')
except:
	print('rollback')
	db.rollback()
finally:
	if db:
		db.close()

step5:查询数据表

import pymysql
db = pymysql.connect(host='localhost',user='root',password='root',database='test')
cursor = db.cursor()
sql = "SELECT * FROM EMPLOYEE"
try:
   # 执行SQL语句
	cursor.execute(sql)
	results = cursor.fetchall()
	for row in results:
		fname = row[0]
		lname = row[1]
		age = row[2]
		sex = row[3]
		income = row[4]
		print ("fname=%s,lname=%s,age=%s,sex=%s,income=%s" % (fname, lname, age, sex, income ))
except:
   print ("Error: unable to fecth data")

# 关闭数据库连接
db.close()

step6 :更新是数据表

import pymysql
db = pymysql.connect(host='localhost',user='root',password='root',database='test')
cursor = db.cursor()
sql = "UPDATE EMPLOYEE SET AGE = AGE + 1 WHERE SEX = '%c'" % ('M')
try:
	cursor.execute(sql)
   # 提交到数据库执行
	db.commit()
except:
   # 发生错误时回滚
	db.rollback()
db.close()

step7:删除数据表

import pymysql
db = pymysql.connect(host='localhost',user='root',password='root',database='test')
cursor = db.cursor()
sql = "DELETE FROM EMPLOYEE WHERE AGE > %s" % (20)
try:
   # 执行SQL语句
	cursor.execute(sql)
   # 提交修改
	db.commit()
	print('删除成功')
except:
   # 发生错误时回滚
	db.rollback()
	print('rollback')
# 关闭连接
db.close()