无法让我在 Sqlite3 中的数据库接受文本

Question

我有一个 python 程序正在尝试将条目写入数据库。 代码成功执行，并创建了销售表中的条目，但是当我在 DB Browser 中检查数据库中的 SQLite 时，它显示文本列为空白。 以下是代码的相关部分：

class SDB:
    def __init__(self):
        self.conn = sqlite3.connect("sales.db")
        self.cur = self.conn.cursor()
        self.cur.execute(
            "CREATE TABLE IF NOT EXISTS sales (orderID INTEGER PRIMARY KEY, customer TEXT, itemPurchased TEXT)")
        self.conn.commit()

    def __del__(self):
        self.conn.close()

    def view(self):
        self.cur.execute("SELECT * FROM sales")
        rows = self.cur.fetchall()
        return rows

    def search(self, customer="", itemPurchased=""):
        self.cur.execute("SELECT * FROM sales WHERE customer=? OR itemPurchased=?", (customer, itemPurchased,))
        rows = self.cur.fetchall()
        return rows

    def purchase(self, customer, itemPurchased):
        orderID=randint(1000, 9999)
        self.cur.execute("INSERT INTO sales (orderID, customer, itemPurchased) VALUES (?, ?, ?)", (orderID, customer, itemPurchased,))
        self.conn.commit()
        print("Order Placed!")

sbd = SDB()

这是 python 中的数据库定义，function购买由 tkinter window 调用：

purchase_window = tk.Tk()
    purchase_window.title('Purchase Books')
    window_width = 300
    window_height = 200
    screen_width = purchase_window.winfo_screenwidth()
    screen_height = purchase_window.winfo_screenheight()
    center_x = int(screen_width / 2 - window_width / 2)
    center_y = int(screen_height / 2 - window_height / 2)
    purchase_window.geometry(f'{window_width}x{window_height}+{center_x}+{center_y}')
    
    itemLabel = ttk.Label(purchase_window, text="Book Title")
    itemEntry = ttk.Entry(purchase_window)
    customerLabel = ttk.Label(purchase_window, text="Your Name")
    customerEntry = ttk.Entry(purchase_window)
    
    itemPurchased = itemEntry.get()
    customer = customerEntry.get()
    orderButton = ttk.Button(purchase_window, text="Purchase", command=sbd.purchase(customer, itemPurchased))
    
    itemLabel.grid(row=0, column=0)
    itemEntry.grid(row=0, column=1)
    customerLabel.grid(row=1, column=0)
    customerEntry.grid(row=1, column=1)
    orderButton.grid(row=2, column=1)

如您所见，代码应该插入客户姓名、他们订购的书名和随机生成的订单 ID。 订单 ID 很好地插入到数据库中，但文本项没有。 这是怎么回事？

Answer 1

您的代码中几乎没有问题：

• 对orderID列使用random.randint()的结果可能会导致重复错误，请改用orderID列上的AUTOINCREMENT功能

CREATE TABLE IF NOT EXISTS sales (orderID INTEGER PRIMARY KEY AUTOINCREMENT, customer TEXT, itemPurchased TEXT)

• 您在创建itemEntry和customerEntry后立即获得它们的内容，因此itemPurchased和customer由于尚未输入而为空字符串。 您需要在sbd.purchase()中调用那些.get()

def purchase(self):
    # get the required content from entries
    customer = customerEntry.get()
    itemPurchased = itemEntry.get()
    # removed orderID as it is an autoincrement column now
    self.cur.execute("INSERT INTO sales (customer, itemPurchased) VALUES (?, ?)", (customer, itemPurchased))
    self.conn.commit()
    print("Order Placed!")

• command=sbd.purchase(customer, itemPurchased)将立即执行sbd.purchase() ，而不是在单击按钮时执行。 使用command=sbd.purchase并重新定义sbd.purchase()而无需 arguments 如上所述。

orderButton = ttk.Button(purchase_window, text="Purchase", command=sbd.purchase)