无法弄清楚如何在项目中表达我的逻辑

Question

well done. i have got to admit that stack overflow has helped me when all seemed dreadful. in my simple application, i need when a person books a room,

1. it shows a confirmation message

2. there is an auto decrement in book number ie let's say, if there are 40 rooms, after a single book they are decremented to 39

3. to make sure one person can book only once.

   though the code i have been putting seemed wrong and irrelevant, any help given is appreciated. is the logic put in models or views, and if yes, just show me atleast a line of code how it can be iniciated.

models.py

class Booking(models.Model):
    Book_No = models.IntegerField(default=1)
    Hostel = models.ForeignKey(List, null=True, blank=True)
    Room_Number = models.ForeignKey(Room)
    Room_capacity = models.CharField(max_length=1, choices=[('S', 'Single'), ('D', 'Double')], default="--")
    Booked_by = models.ForeignKey(Student, default='--')
    Booked_on = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '{}, booked a {} room in {} {} at {}'.format(
            self.Booked_by, self.Room_capacity, self.Hostel, self.Room_Number, self.Booked_on)

views.py

def book(request):
    if request.method == "POST":
        form = BookForm(request.POST)
        if form.is_valid():
            post = form.save(commit=True)
            post.save()
    else:
        form = BookForm()
    return render(request, 'gyobera/book_now.html', {'form': form})

forms.py

class BookForm(forms.ModelForm):
    class Meta:
        model = Booking
        fields = ('Book_No', 'Hostel', 'Room_Number', 'Room_capacity', 'Booked_by')

book_now.html

{% extends 'base.html' %}

{% load staticfiles %}

{% block title %}{{ classification_name }}{% endblock %}

{% block body_block %}
        <h1>Book_now</h1> <a href="/Gyobera/">Home</a><br/>
<br/>
    <form method="POST" class="post-form">{% csrf_token %}
        {{ form.as_p }}
        <button type="submit" class="save btn btn-default">Book_now</button>
    </form>
{% endblock %}

thanks

i chose to edit and post the question here since it's more similar like the one i had posted above.. i have these here: below is my view to pull the available rooms from the database to be viewed on the site and the book view. in my appplication you can book a hostel but when you book it off, it doesn't show or simply put it remains in the database as an available room, the code i had written seems totally wrong and irrelevant, i seek some help please.. then what is the simplest way i can filter hostels availed to make sure if a male is booking, hostels of that gender are only availed. i hope the code below would really work to aid help. thanks

views.py

def rooms(request):
    context_dict = {}
    context = RequestContext(request)
    room_list = Room.objects.all()
    for room in room_list:
        context_dict = {'rooms': room_list}
    return render_to_response('gyobera/room.html', context_dict, context)

def book(request):
    # check if user has already booked:
    has_booked = Booking.objects.filter(Booked_by_id=request.POST.get('booked_by')).exists()
    # are room free?
    rooms_full = Booking.objects.count() == 40
    if rooms_full or has_booked:
        # redirect to a error view
        return 'You have reserved yourself a room'

    if request.method == "POST":
        form = BookForm(request.POST)
        if form.is_valid():
            post = form.save(commit=True)
            post.save()
    else:
        form = BookForm()
    return render(request, 'gyobera/book_now.html', {'form': form})

models.py

class Room(models.Model):
    Hostel = models.ForeignKey(List)
    Room_Number = models.CharField(max_length=50)
    Total_rooms = models.IntegerField(default=0, blank=True)
    Price_single = models.IntegerField(default=0, blank=True)
    Price_double = models.IntegerField(default=0, blank=True)

    def __str__(self):
        return ' {}   |   {} '.format(self.Hostel, self.Room_Number)


class Booking(models.Model):
    Book_No = models.IntegerField(default=1)
    Gender = models.CharField(max_length=1, choices=[('M', 'Male'), ('F', 'Female')], default="--")
    Hostel = models.ForeignKey(List, null=True, blank=True)
    Room_Number = models.ForeignKey(Room)
    Room_capacity = models.CharField(max_length=1, choices=[('S', 'Single'), ('D', 'Double')], default="--")
    Booked_by = models.ForeignKey(Student, default='--')
    Booked_on = models.DateTimeField(auto_now_add=True)

    def __str__(self):
        return '{}, {} booked a {} room in {} {} at {}'.format(
            self.Booked_by, self.Gender, self.Room_capacity, self.Hostel, self.Room_Number, self.Booked_on)

room.html

{% extends 'base.html' %}

{% load staticfiles %}

{% block title %}{{ category_name }}{% endblock %}

{% block body_block %}
    <h1><strong>Available rooms </strong></h1><a href="/Gyobera/">Home</a><br/>
          {% if rooms %}
            <ul>
                {% for room in rooms %}
                 <!-- Following line changed to add an HTML hyperlink -->
                <li><a href="{{ room_list}}">{{ room }}</a></li>
                {% endfor %}
            </ul>
        {% else %}
            <strong>There are no rooms in this hostel.</strong>
        {% endif %}
{% endblock %}

Answer 1

There are many ways to achieve this. The simplest is to add this in the view. There you have to check, if the user has already booked and if there are still rooms free.

def book(request):
    # check if user has already booked:
    has_booked = Booking.objects.filter(booked_by=request.user).exists()
    # are room free?
    rooms_full = Booking.objects.count() == 40
    if rooms_full or has_booked:
        # redirect to a error view
        return ...


    if request.method == "POST":
        form = BookForm(request.POST)
        if form.is_valid():
            post = form.save(commit=True)
            post.save()
    else:
        form = BookForm()
    return render(request, 'gyobera/book_now.html', {'form': form})