插入到通过 FOREIGN KEY 链接到第二个表的 2 个表中，并从 sqlite 和 python 中的另一个表中获取数据

Question

I have 3 tables and this is the scheme for this table

the first one is the product that has all products and the price and the margin of this product

the sconde one is the general bill that have information about the client and the total

The 3rd one is the problem;

I have to enter the id of the product in products

And number of products

And the prix should be extracted from the product table and multiplied by the number of products

the same for margin

and the general bill id have to be the same as the general_bill

and after that update the general bill with information about the total and total profit that have the same id from the table detail bill

for now I only figure out the simplest thing

import sqlite3
import time, datetime
from datetime import timedelta

class Crud_db:
    def __init__(self, database = 'database.db'):
        self.database = database

    def connect(self):
        self.connection = sqlite3.connect(self.database)
        self.cursor = self.connection.cursor()
        print('connect seccesfully')

    def execute(self, query):
        self.query = query
        self.cursor.execute(self.query)

    def close(self): 
        self.connection.commit()
        self.connection.close()

    def create_tables(self):
        # create all tables

    def insert_new_bill(self):
        self.connect()
        date_f = str(datetime.date.today())
        time_f = str(datetime.datetime.now().time())
        client_name = input('client name: ')
        query01 = 'INSERT INTO general_bill (client_name, date_g, time_g) VALUES (?, ?, ?)'
        data = (client_name,date_f, time_f)
        self.cursor.execute(query01,data) 
        self.close()
        print('added to general bill ..!')



    def add_product(self):
        self.connect()
        product_name = input('product name: ')
        prix = float(input('the price : '))
        royltie = float(input('profit: '))
        product_discreption = input('discreption: ')
        product_query = 'INSERT INTO product (product_name, prix, royltie, product_descreption) VALUES (?,?,?,?)'
        data_set = [product_name,prix,royltie,product_discreption]
        self.cursor.execute(product_query,data_set) 
        self.close()
        print(f'product {product_name} added to database')
        question = input('do you wana add more products ?(yes/no): ')
        if question.lower() == 'yes':
            self.add_product()
        else:
            pass

Answer 1

I find a solution that work for me, I don't know if it is the best one, or if there is a way to make it easier but this is my solution

    def insert_new_bill(self):

        self.connect()
        date_f = str(datetime.date.today())
        time_f = str(datetime.datetime.now().time())



        client_name = input('client name: ')
        query01 = 'INSERT INTO general_bill (client_name, date_g, time_g) VALUES (?, ?, ?)'
        data = (client_name,date_f, time_f)
        self.cursor.execute(query01,data) 
        print('added to general bill ..!')
        # add the detail of this bill 
        question = 'yes'
        while question == 'yes':
            product = input('product id: ')
            number_of_product = input('number of product: ')

            query2 = 'INSERT INTO details_bill (products, number_of_products, prix, royltie, date,time, general_bill_id) VALUES (?,?,?*(select prix from product where id =?),?*(select royltie from product where id =?),?,?,(select max(id) from general_bill where client_name = ?))'
            data_query_2 = (product, number_of_product, number_of_product, product, number_of_product, product, date_f, time_f, client_name)
            self.cursor.execute(query2,data_query_2)
            question = input('do you wana add more product for this client (yes/no): ')
        else:
  
            query_3 = 'UPDATE general_bill SET total = (SELECT SUM(prix) FROM details_bill WHERE general_bill_id = (select max(id) from general_bill where client_name = ?) ), number_of_products = (SELECT SUM(number_of_products) FROM details_bill WHERE general_bill_id = (select max(id) from general_bill where client_name = ?) ) WHERE id = (select max(id) from general_bill where client_name = ?)'
            data_query_3 = (client_name, client_name, client_name)
            self.cursor.execute(query_3,data_query_3) 
            print(f'all product that |{client_name}| buy added to database seccesfully')
            self.close()