Question

我对python和flask很新。基本上我构建了一个非常基本的Web应用程序，允许管理员添加/编辑/删除用户列表。列表显示在主菜单上，管理员可以在第一时间添加/编辑/删除。但是当我尝试第二次添加/编辑/删除时它不起作用，如果我在添加/编辑/删除后重定向回主菜单（用户列表所在的位置），它也会失败。任何想法可能是什么问题？

from flask import Flask, url_for, request, render_template, redirect;
from app import app;
import pypyodbc;

myConnection = pypyodbc.connect('Driver={SQL Server};'
                                'Server=local'
                                'Database=All;'
                                'uid=sa;pwd=23232')
myCursor = myConnection.cursor()
myCursor.execute('SELECT * FROM Users')
rows = myCursor.fetchall();

for r in rows:
    print(r)


@app.route('/')
def home():
    """Renders a sample page."""
    createLink = "<a href='" + url_for("display") + "'>Admin</a>";
    createLink2 = "<a href='" + url_for("user") + "'>User login</a>";
    createLink3 = "<a href='" + url_for("delete") + "'>Delete</a>";
    createLink4 = "<a href='" + url_for("edit") + "'>Edit</a>";
    return """<html>
                    <head>
                        <title>First page</title>
                    </head>
                        <body>
                            <h1>Menu</h1>
                            <div>
                            """ + createLink + """
                            </div>
                            <div>
                            """ + createLink2 + """
                            </div>
                            <div>
                            """ + createLink3 + """
                            </div>
                            <div>
                            """ + createLink4 + """
                            </div>
                        </body>
              </html>"""
@app.route('/display', methods=['GET', 'POST'])
def display():
    if request.method == 'GET':
        myCursor = myConnection.cursor()
        myCursor.execute('SELECT * FROM Users')
        rows = [dict(id=row[0], name=row[1], email=row[2], password=row[3]) for row in myCursor.fetchall()]
        return render_template('DisplayAll.html', rows = rows)
    else:
        return"<h2>Error</h2>"

@app.route('/add', methods=['GET', 'POST'])
def add():
    if request.method == 'GET':
        return render_template('Add.html');
    elif request.method == 'POST':
        name = request.form['AddName'];
        email = request.form['AddEmail'];
        password = request.form['AddPassword'];

        SQLCommand = ("INSERT INTO Users "
                  "(Name, Email, Pword) "
                  "VALUES (?,?,?)")
        values = [name, email, password]

        myCursor.execute(SQLCommand,values)
        myConnection.commit();
        #print("works")
        #myCursor.execute('SELECT * FROM Users')
        #rows = [dict(id=row[0], name=row[1], email=row[2], password=row[3]) for row in myCursor.fetchall()]
        myConnection.close();
        return ridirect(url_for('display'));

    else:
        return "<h2>Error</h2>";

@app.route('/delete', methods=['GET', 'POST'])
def delete():
    if request.method == 'GET':
        return render_template('Delete.html');
    elif request.method == 'POST':
        try:
            DeleteId = request.form['DeleteId'];

            SQLCommand = ("DELETE FROM Users "
                      "WHERE UsererId = "
                      + DeleteId)

            myCursor.execute(SQLCommand)
            myConnection.commit();
            #myCursor.execute('SELECT * FROM Users')
            #rows = [dict(id=row[0], name=row[1], email=row[2], password=row[3]) for row in myCursor.fetchall()]
            myConnection.close();
            #return render_template("DisplayAll.html", rows = rows);
            return redirect(url_for('display'));
        except:
            return "<h2>Doesn't work</h2>"

    else:
        return "<h2>Error</h2>";

@app.route('/edit', methods=['GET', 'POST'])
def edit():
    if request.method == 'GET':
        return render_template('Edit.html');
    elif request.method == 'POST':
        try:
            Name = request.form['EditName'];
            Email = request.form['EditEmail'];
            Password = request.form['EditPassword'];
            EditId = request.form['EditId'];

            SQLCommand = ("UPDATE Users "
                      "SET Name = '" + Name +
                      "', Email = '" + Email +
                      "', Pword = '" + Password +
                      "' WHERE UsererId = "
                      + EditId)

            myCursor.execute(SQLCommand)
            myConnection.commit();
            #print("works")
            #myCursor.execute('SELECT * FROM Users')
            #rows = [dict(id=row[0], name=row[1], email=row[2], password=row[3]) for row in myCursor.fetchall()]
            myConnection.close();
            #return render_template("DisplayAll.html", rows = rows);
            return redirect(url_for('display'));
        except:
            return "<h2>Doesn't work</h2>"

    else:
        return "<h2>Error</h2>";

Answer 1

首先，你在add（）函数中输入了一个拼写错误。这一行：

return ridirect(url_for('display'));

应该是

return redirect(url_for('display'));

接下来，在display（）中定义myCursor，然后使用它。没关系

myCursor = myConnection.cursor()

但是，在函数添加，删除和编辑中，您缺少此定义，但您仍在使用它。您不能省略此定义，因为第一个定义仅在{（3}}内的display（）内有效。尝试将此定义添加到其他功能。

如果这不起作用，可能是因为您还需要为每个请求建立新连接，而不仅仅是在文件的开头。然后，每个函数将以

开头

myConnection = pypyodbc.connect('Driver={SQL Server};'
                            'Server=local'
                            'Database=All;'
                            'uid=sa;pwd=23232')
myCursor = myConnection.cursor()

请告诉我们这是否适合您。

注意：我刚刚注意到在使用myConnection.close()添加/删除/编辑后，您实际上正在关闭连接。因此，您肯定需要使用上面的代码在每个请求时重新打开连接。

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1 个答案: