Python 笔记07（Mysql数据库基本操作）

一 数据插入

1.1 创建数据列

1.1.1 选择数据库

USE test_data;

1.1.2 插入数据列

ALTER TABLE test_data_info
ADD COLUMN stuno INT,
ADD COLUMN stuname VARCHAR(255),
ADD COLUMN gender VARCHAR(10);

1.2 插入具体数据

import MySQLdb

# 创建数据库连接  # 主机IP：192.168.146.1，本机可以使用local_host
conn = MySQLdb.connect(host='127.0.0.1', port=3306, user='root', password='root', db='test_data')
# print('conn:', conn)

# 获取游标对象
cursor = conn.cursor()   # cursor 游标

sql = 'insert into test_data_info(stuno, stuname, gender) values(%s,%s,%s)'

try:
    result = cursor.execute(sql, args=(1042, 'rose', 'girl'))   # 增，删，改，需要提交  # execute，执行
    print('result:', result)
    conn.commit()    # 提交  # commit
except Exception as ex:
    print(ex)
    conn.rollback()  # 记得回滚

1.3 查询数据

1.3.1 查询多条数据

sql = 'select * from test_data_info'

cursor.execute(sql)
result = cursor.fetchall()
print('result:', result)

1.3.2 查询单条数据

sql = 'select count(*) from test_data_info'

cursor.execute(sql)
result = cursor.fetchone()
print('result:', result)

1.4 命令行操作

1.4.1 命令行操作

Windows + r   -> cmd

1.4.2 登录MySQL

mysql -h127.0.0.1 -uroot -proot

1.4.3 选择数据库

use test_data

1.4.4 查看存在的表格

show tables;

1.4.5 查看具体表格

select * from test_data_info;

1.4.6 插入数据

insert into test_data_info(stuno, stuname, gender) values (1043, 'mark', 'boy');

二 数据库内容修改

2.1 配置文件一

class DBConfig:
    db_host = '127.0.0.1'
    db_port = 3306
    db_user = 'root'
    db_password = 'root'
    db_database = 'test_data'

2.2 配置文件二

import MySQLdb
class MySQLClientUtils(object):
    def __init__(self, config):
        self.host = config.db_host
        self.port = config.db_port
        self.user = config.db_user
        self.pwd = config.db_password
        self.db = config.db_database
        self.conn = None
        self.cursor = None

    # 创建链接
    def create_connection(self):
        self.conn = MySQLdb.connect(host=self.host, port=self.port, user=self.user, password=self.pwd, db=self.db)

    # 获取游标对象
    def create_cursor(self):
        self.cursor = self.conn.cursor(MySQLdb.cursors.DictCursor)

    # 关闭
    def close(self):
        if self.cursor:
            self.cursor.close()
        if self.conn:
            self.conn.close()

    # 关于数据库的操作, 增删改查, insert, delete, update,
    def dml_operation(self, sql, args=None):
        try:
            # 获取连接对象
            self.create_connection()
            # 获取游标
            self.create_cursor()
            # 执行sql语句
            result = self.cursor.execute(sql, args=args)   # 执行sql语句并传参
            # 提交
            self.conn.commit()
            return result

        except Exception as ex:
            print('ex: ', ex)
            self.conn.rollback()
        finally:
            self.close()   # 正常结束，调用关闭操作

    # 查询操作
    def search_operation(self, sql, args=None, is_one=True):
        try:
            # 创建链接
            self.create_connection()
            # 获取cursor
            self.create_cursor()
            # 执行sql语句
            self.cursor.execute(sql, args=args)
            if is_one:
                result = self.cursor.fetchone()  # 查询一个结果
            else:
                result = self.cursor.fetchall()  #
            return result  # 返回查询结果

        except Exception as ex:
            print('ex: ', ex)
        finally:
            self.close()  # 关闭

2.3 插入数据

2.3.1 插入数据

sql1 = 'insert into test_data_info(stuno, stuname, gender) values(%s,%s,%s)'

# 创建对象
client_utils = MySQLClientUtils(DBConfig)
result = client_utils.dml_operation(sql1, args=(1048, '张三', 'boy'))
print(result)

2.3.2 修改数据

from settings import DBConfig
from mysql_utils import MySQLClientUtils

sql2 = 'update test_data_info set stuname=%s where stuno=%s'
# 创建对象
client_utils = MySQLClientUtils(DBConfig)
result = client_utils.dml_operation(sql2, args=('张小亮', 1048))
print(result)

2.3.3 修改数据

sql3 = 'delete from test_data_info where stuno=%s'

# 创建对象
client_utils = MySQLClientUtils(DBConfig)
result = client_utils.dml_operation(sql3, args=(1048, ))
print(result)

2.3.4 查询数据

sql4 = 'select count(*) from test_data_info'

# 创建对象
client_utils = MySQLClientUtils(DBConfig)
result = client_utils.search_operation(sql4)
print(result)

2.3.5 模糊查询

sql5 = 'select * from test_data_info where stuname like %s'

# 创建对象
client_utils = MySQLClientUtils(DBConfig)
result = client_utils.search_operation(sql5, args=('%ma%', ), is_one=False)
print(result)

三 实际项目数据库操作

3.1 进入主界面

from settings import DBConfig
from mysql_utils import MySQLClientUtils
import prettytable as pt

# 面向过程
def menu():
    while True:
        print('-' * 50, '欢迎来到购物商城', '-' * 50)
        print('1.查询全部商品 2.根据商品名称查询 3.根据编号查询 4.新增商品进购物车 5.清空购物车 6.删除购物车中指定商品 '
              '7.查询购物车 0.退出系统')
        print('-'*120)
        choice = eval(input('请选择：'))
        if choice == 1:
            # 调用查询方法
            result = search_all()
            show(result)

        elif choice == 2:
            goods_name = input('请输入要查询的商品名称【支持模糊查询】：')
            # 调用本模块中根据商品名称查询的方法
            result = search_by_name(goods_name)
            show(result)

        elif choice == 3:
            goods_id = eval(input('请输入要查询的商品编号：'))
            # 调用本模块中根据商品名称查询的方法
            result = search_by_id(goods_id)
            show(result)

        elif choice == 4:
            goods_id = eval(input('请输入想要购买的商品编号: '))
            result = search_by_id(goods_id)[0]
            print('result:', result)
            # result: ({'id': '51.0', 'name': '项目驱动零起点学Java 百万程序员Java学习经验总结', 'price': '49.0'},)
            goods_name = result.get('name')
            price = result.get('price')
            num = eval(input('请输入要购买的数量：'))
            # 调用本模块的添加进购物车的方法
            insert_result = add_cart(goods_id, goods_name, price, num)
            if insert_result > 0:
                print('商品已经添加到购物车！')
            else:
                print('添加失败')

        elif choice == 5:
            # 清空购物车
            result = clear_cart()
            if result > 0:
                print('成功清空购物车')
            else:
                print('购物车中无商品！')

        elif choice == 6:
            """6.删除购物车中指定商品"""
            goods_id = eval(input('请输入要删除的商品编号： '))
            result = delete_goods_in_cart(goods_id)
            print('result:', result)
            if result > 0:
                print('删除购物车商品成功')
            else:
                print('购物车中无商品')

        elif choice == 7:
            """7.查询购物车"""
            result = search_cart()
            show_cart(result)

        elif choice == 0:
            print('谢谢使用 ！')
            break
        else:
            print('输入错误，重新选择')

if __name__ == '__main__':
    menu()

3.2  查询全部商品

sql = 'select * from yanxuan'

def search_all():
    """查询全部商品"""
    sql = 'select * from yanxuan'
    # 调用数据库查询
    result = MySQLClientUtils(config=DBConfig).search_operation(sql, is_one=False)
    return result

def show(result):
    """数据显示"""
    tb = pt.PrettyTable()
    tb.field_names = ['编号', '商品名称', '售价']
    for item in result:
        id = item.get('id')
        name = item.get('name')
        price = item.get('price')
        lst = [id, name, price]
        tb.add_row(lst)  # 添加到表格中
    print('tb:', tb)

3.3 根据商品名称查询

sql = 'select * from yanxuan where name like %s'

def search_by_name(goods_name):
    sql = 'select * from yanxuan where name like %s'
    # 调用数据库查询
    result = MySQLClientUtils(config=DBConfig).search_operation(sql, args=(f'%{goods_name}%',), is_one=False)
    return result

3.4 根据编号查询

sql = 'select * from yanxuan where id = %s'

def search_by_id(goods_id):
    sql = 'select * from yanxuan where id = %s'
    # 调用数据库查询
    result = MySQLClientUtils(config=DBConfig).search_operation(sql, args=(goods_id,), is_one=False)
    return result

sql = 'insert into cart (goods_id, name, price, num) value (%s, %s, %s, %s)'

def add_cart(id, goods_name, price, num):
    sql = 'insert into cart (goods_id, name, price, num) value (%s, %s, %s, %s)'
    result = MySQLClientUtils(config=DBConfig).dml_operation(sql, args=(id, goods_name, price, num))
    return result

3.5 清空购物车

sql = 'delete from cart'

def clear_cart():
    """清空购物车"""
    sql = 'delete from cart'
    result = MySQLClientUtils(config=DBConfig).dml_operation(sql)
    return result

3.6 删除购物车指定商品

sql = 'delete from cart where goods_id=%s'

def delete_goods_in_cart(goods_id):
    """删除购物车指定商品"""
    sql = 'delete from cart where goods_id=%s'
    result = MySQLClientUtils(config=DBConfig).dml_operation(sql, args=(goods_id, ))
    return result

3.7 查询购物车所有商品

sql = 'select * from cart'

def search_cart():
    """查询购物车所有商品"""
    sql = 'select * from cart'
    result = MySQLClientUtils(config=DBConfig).search_operation(sql, is_one=False)
    return result

显示购物车商品：

def show_cart(result):
    tb = pt.PrettyTable()
    tb.field_names = ['序号', '商品编号', '商品名称', '售价', '数量']
    for item in result:
        id = item.get('id')
        goods_id = item.get('goods_id')
        name = item.get('name')
        price = item.get('price')
        num = item.get('num')
        lst = [id, goods_id, name, price, num]
        tb.add_row(lst)
    print(tb)