Python对MySQL进行增删查改

Posted 2020-11-26 D

python连接MySQL数据库：pymysql

# 测试操作
import pymysql

# 打开数据库
db = pymysql.connect("localhost", "root", "test1234", "pythontest", charset=\'utf8\' )
# 使用cursor()方法获取操作游标
cursor = db.cursor()
# 使用execute执行sql语句
cursor.execute("select * from user")
data = cursor.fetchall()
print(data)
db.close()

数据库user表：

 

 User类：

class User:

    def __init__(self, id, username, birth_data, money, father, mother):
        self.id = id
        self.username = username
        self.birth_data = birth_data
        self.money = money
        self.father = father
        self.mother = mother

    def set_username(self, name):
        self.username = name

    def get_username(self):
        return self.username

    def set_money(self, money):
        self.money = money

    def get_money(self):
        return self.money

    def print(self):
        if self.father == None:
            # print("id:", self.id, " father= NULL mother=NULL")
            print("id: {} username: {} father= NULL mother= NULL".format(self.id, self.username))
        else:
            # print("id:", self.id, " father=", self.father.username, "  mother=", self.mother.username)
            print("id: {} username: {}".format(self.id, self.username))

增删查改：

# 增删查改
from Practice_Recode.UserTest.User import User
import pymysql


def openDb():
    global db, cursor
    db = pymysql.connect("localhost", "root", "test1234", "pythontest", charset=\'utf8\')
    cursor = db.cursor()


def closeDb():
    db.close()


# 按照用户id查询用户记录(输出相应内容，并返回查到的user对象)
def serarchDb(id):
    openDb()
    sql = "select * from user where id = " + str(id)
    rst = cursor.execute(sql)
    if rst == 0:
        # print("查找失败")
        return None
    else:
        # print("查找成功")
        data = cursor.fetchone()
        # print(data)
        user1 = User(data[0], data[1], data[2], int(data[3]), data[4], data[5])
        return user1
    closeDb()


# 按照用户id删除用户记录
def deleteDb(id):
    openDb()
    sql = "delete from user where id = " + str(id)
    rst = cursor.execute(sql)
    if rst == 0:
        print("删除失败")
    else:
        print("删除成功")
    closeDb()


# 新增用户
def insertDb(user1):
    openDb()
    sql = "insert into user values(\'%d\',\'%s\',\'%s\',\'%d\',\'%s\',\'%s\')" % (
        user1.id, user1.username, user1.birth_data, user1.money, user1.father, user1.mother)
    # "INSERT INTO mytb(title,keywd) VALUES(\'%s\',\'%s\')"%(x,y)
    cursor.execute(sql)
    db.commit()
    closeDb()


# 更新用户信息
def updateDb(user1):
    openDb()
    sql = "update user set username = \'%s\', money=\'%d\' where id=\'%d\'" % (user1.username, user1.money, user1.id)
    # update user set username=\'C\', money=9999 where id=5;
    rst = cursor.execute(sql)
    if rst == 0:
        print("更新失败")
    else:
        print("更新成功")
    closeDb()

#  测试数据
# testuser = serarchDb(5)
# testuser.set_username(\'C\')
# testuser.set_money(9082)
# # print(testuser.id, testuser.username, testuser.money, testuser.father, testuser.mother)
# updateDb(testuser)

# user1 = User(5, "c", "1111-03-11", 10000, father=\'A\', mother=\'a\')
# insertDb(user1)
# user2 = User(0, "d", "1111-03-11", 10000, \'A\', \'a\')  # 自增键id设置为0，新增时即可实现自增
# insertDb(user2)

# user2 = User(1, "A", "1111-03-11", 10000, father=None, mother=None)
# user3 = User(2, "a", "1111-03-11", 10000, father=None, mother=None)
# user1 = User(3, "B", "1111-03-11", 10000, user2, user3)
# user1.dayin()
# user1.father.dayin()

查找某个用户的祖辈：

# 查找当前user所有的亲缘关系
# father,monther,father\'s father,fahter\'s mother

from Practice_Recode.UserTest.test02 import *
import pymysql


def openDb():
    global db, cursor
    db = pymysql.connect("localhost", "root", "test1234", "pythontest", charset=\'utf8\')
    cursor = db.cursor()


def closeDb():
    db.close()


# 查找所有用户id,并返回ids,users
def serarchDbAll():
    openDb()
    ids = []
    users = []
    sql = "select * from user"
    rst = cursor.execute(sql)
    if rst == 0:
        # print("查找失败")
        return None
    else:
        # print("查找成功")
        data = cursor.fetchall()
        for i in range(len(data)):
            user = User(0, "", "", 0, "", "")
            user.id = data[i][0]
            user.username = data[i][1]
            user.birth_data = data[i][2]
            user.money = data[i][3]
            user.father = data[i][4]
            user.mother = data[i][5]
            users.append(user)
            ids.append(data[i][0])
    closeDb()
    return ids, users


# 根据名字返回这个人用户对象（未考虑重名问题）
def NameSearchUser(name):
    ids, users = serarchDbAll()
    for user in users:
        if user.username == name:
            return user
    return None


# 找某用户的爸爸用户
def searchFa(user):
    if user.father != None:
        fauser = NameSearchUser(user.father)  # 根据爸爸的名字返回爸爸用户
        if fauser != None:
            print("他的名字是：", fauser.username)
            return fauser
    print("他的名字为空")
    return None


# 找某用户的妈妈用户
def searchMo(user):
    if user.mother != None:
        mouser = NameSearchUser(user.mother)  # 根据名字返回妈妈用户
        if mouser != None:
            print("她的名字是：", mouser.username)
            return mouser
    print("她的名字为空")
    return None


# 查找13号的祖先
currentuser = serarchDb(13)  # 得到13号用户本人
print("当前用户是：", currentuser.username)

print("当前用户的父亲是：")
cur_fa = searchFa(currentuser)  # 得到当前用户的父亲
print(cur_fa)

print("当前用户的母亲是：")
cur_mo = searchMo(currentuser)  # 得到当前用户的母亲
print(cur_mo)

print("当前用户的爷爷:")
cur_fa_fa = searchFa(cur_fa)  # 得到当前用户的爷爷
print(cur_fa_fa)

print("当前用户的奶奶:")
cur_fa_mo = searchMo(cur_fa)  # 得到当前用户的奶奶
print(cur_fa_mo)

print("当前用户的姥爷:")
cur_mo_fa = searchFa(cur_mo)  # 得到当前用户的姥爷
print(cur_mo_fa)

print("得到当前用户的姥姥:")
cur_mo_mo = searchMo(cur_mo)  # 得到当前用户的姥姥
print(cur_mo_mo)