MySQL数据库查询返回的是整数而不是行数据

问题描述

我试图测试数据库中是否已经存在以表单（电子邮件地址和密码）提交的信息。如果电子邮件存在，我要检查数据库中相应的哈希密码是否与提交的密码的哈希版本匹配。

以下是我的登录路线的完整摘录：

# Login route
@app.route("/login",methods=["GET","POST"])
def login():
    """Log user in"""

    # Forget any user_id
    session.clear()

    # User reached route via POST (as by submitting a form via POST)
    if request.method == "POST":

        # Create a cursor
        cur = MysqL.connection.cursor()

        # Ensure email was submitted
        if not request.form.get("email"):
            return apology("must provide email",403)

        # Ensure password was submitted
        elif not request.form.get("password"):
            return apology("must provide password",403)

        # Store email in a variable
        email = request.form.get("email")

        # Query if email is within database
        query = cur.execute("SELECT * FROM users WHERE email = %s",(email,))

        # Ensure email exists and that the password is correct
        if len(query) != 1 or not check_password_hash(query[0]["hashedpassword"],request.form.get("password")):
            return apology("invalid email and/or password",403)

        # Remember which user has logged in
        session["user_id"] = query[0]["id"]

        # Redirect user to the homepage
        return redirect("/")

    # User reached route via GET (as by clicking a link or via redirect)
    else:
        return render_template("login.html")

我遇到困难的部分是：

        # Ensure email exists and that the password is correct
        if len(query) != 1 or not check_password_hash(query[0]["hashedpassword"],403)

在这里，我正在尝试从数据库中为指定的电子邮件地址提取一行信息。我试图使用len来查看是否存在单行（由于我已确保数据库中的电子邮件地址列是唯一的，所以不能存在两行），因此应该是单行或无行。

问题是我以前的数据库查询返回一个整数值（查询= 1），如以下错误所示：

[2020-10-05 11:34:27,857] ERROR in app: Exception on /login [POST]
Traceback (most recent call last):
  File "c:\users\tjmce\appdata\local\programs\python\python38-32\lib\site-packages\flask\app.py",line 2447,in wsgi_app
    response = self.full_dispatch_request()
  File "c:\users\tjmce\appdata\local\programs\python\python38-32\lib\site-packages\flask\app.py",line 1952,in full_dispatch_request
    rv = self.handle_user_exception(e)
  File "c:\users\tjmce\appdata\local\programs\python\python38-32\lib\site-packages\flask\app.py",line 1821,in handle_user_exception
    reraise(exc_type,exc_value,tb)
  File "c:\users\tjmce\appdata\local\programs\python\python38-32\lib\site-packages\flask\_compat.py",line 39,in reraise
    raise value
  File "c:\users\tjmce\appdata\local\programs\python\python38-32\lib\site-packages\flask\app.py",line 1950,in full_dispatch_request
    rv = self.dispatch_request()
  File "c:\users\tjmce\appdata\local\programs\python\python38-32\lib\site-packages\flask\app.py",line 1936,in dispatch_request
    return self.view_functions[rule.endpoint](**req.view_args)
  File "C:\Users\tjmce\Desktop\Final Project\app.py",line 81,in login
    if len(query) != 1 or not check_password_hash(query[0]["hashedpassword"],request.form.get("password")):
TypeError: object of type 'int' has no len()

有人可以帮我理解为什么查询的值为1而不是行数据吗？

谢谢！

解决方法

您缺少的部分是

rows = cursor.fetchall()

它将把数据返回给您，您将能够在rows上实现逻辑