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python对mysql的增删改查

Pythonmysql 增删 改查
2023-09-11 14:14:27 时间

python操作mysql数据库——增删改查操作(二)

2019/10/18 11:11
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                                                                                                                                                                                    <p>前面一篇介绍了如何连接数据库,这一篇主要是介绍如何对数据库进行增删改查的操作。</p> 

完整的Python操作mysql数据库脚本如下

# coding = utf -8
import pymysql

class Mysql(object):
def __init__(self):
try:
self.conn = pymysql.connect(
host = '39.108.237.57',
port = 3306,
user = 'root',
passwd = '380475066lhJ',
db = 'test',
charset = 'utf8',
)
except Exception as e:
print(e)
else:
print("connect successfully")

#使用cursor()方法创建一个游标对象cursor
self.cur = self.conn.cursor()


#创建表
def creat_table(self):
try:
#使用execute()方法执行SQL语句,如果表存在则删除
self.cur.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 )"""
#执行SQL语句
self.cur.execute(sql)
print("create table success")
except Exception as e:
print("create table error\n "+e)



#向数据库表中插入数据
def add(self):
sql = """insert into EMPLOYEE(FIRST_NAME,LAST_NAME,AGE,SEX,INCOME)
VALUES ("John","jack",25,"F",8000)"""
try:
self.cur.execute(sql)
#提交到数据库执行
self.conn.commit()
except Exception as e:
print(e)
#发生错误回滚
self.conn.rollback()
print("fail to add new data")
else:
print("insert data success")



#向数据库表中查询数据
def show(self):
sql = """select * from EMPLOYEE"""
try:
self.cur.execute(sql)
#fetchall()返回的结果是List,list里面再嵌套List
res = self.cur.fetchall()
for row in res:
fname = row[0]
lname = row[1]
age = row[2]
sex = row[3]
income = row[4]
print("fname= %s,lname = %s,age = %d,sex =%s,income = %d"%(fname,lname,age,sex,income))
except Exception as e:
print(e+"select data fail")
else:
print("select data success")



#向数据库中更新数据
def update(self):
sql = """UPDATE EMPLOYEE SET AGE = AGE + 1 WHERE SEX = 'M'"""
try:
self.cur.execute(sql)
self.conn.commit()
except Exception as e:
print(e)
else:
print("updata date success")



#删除数据库中的数据
def rem(self):
sql = """delete from EMPLOYEE where sex = "M" """
try:
self.cur.execute(sql)
self.conn.commit()
except Exception as e:
print(e)
else:
print("delete data success")



#关闭数据库连接
def close(self):
self.cur.close()
self.conn.close()
print("close database success")


if __name__ == "__main__":
mysql = Mysql()
mysql.creat_table()
mysql.add()
mysql.show()
mysql.update()
mysql.rem()
mysql.close()
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                                                                                                                                <p><span class="label">本文转载自:</span>https://www.cnblogs.com/lhj818/p/11696652.html</p>
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