MySQL 数据库查询返回整数而不是行数据

Question

我正在尝试测试以表格形式提交的信息（电子邮件地址和密码）是否已存在于数据库中。如果邮件存在，我想检查数据库中对应的散列密码是否与提交密码的散列版本匹配。

这是我的登录路径的完整摘录：

# 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"], request.form.get("password")):
            return apology("invalid email and/or password", 403)

在这里，我试图从我的数据库中提取指定电子邮件地址的单行信息。我试图使用 len 查看是否存在单行（不能存在两行，因为我已确保电子邮件地址列在数据库中是唯一的），因此应该有单行或 none.

问题是我之前的数据库查询返回一个整数值 (query = 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()

有人能帮我理解为什么查询的值为 1 而不是行数据吗？

谢谢！

Answer 1

您缺少的部分是

rows = cursor.fetchall()

它将 return 数据提供给您，您将能够在 rows

上实现您的逻辑

MySQL 数据库查询返回整数而不是行数据

MySQL database query is returning an integer instead of row data

python

mysql

mysql-python

flask

python-3.x