advance crud

django-admin startproject crudproject
cd crudproject
python manage.py startapp products

INSTALLED_APPS = [
    # ...
    'products',
]

from django.db import models

class Category(models.Model):
    name = models.CharField(max_length=100)
    description = models.TextField(blank=True, null=True)

    def __str__(self):
        return self.name

    class Meta:
        verbose_name_plural = "Categories"

class Product(models.Model):
    name = models.CharField(max_length=200)
    code = models.CharField(max_length=50, unique=True)
    price = models.DecimalField(max_digits=10, decimal_places=2)
    stock = models.PositiveIntegerField(default=0)
    description = models.TextField(blank=True, null=True)
    category = models.ForeignKey(Category, on_delete=models.CASCADE, related_name='products')
    image = models.ImageField(upload_to='products/', blank=True, null=True)
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)

    def __str__(self):
        return self.name

python manage.py makemigrations
python manage.py migrate

from django import forms
from .models import Product, Category

class CategoryForm(forms.ModelForm):
    class Meta:
        model = Category
        fields = ['name', 'description']
        widgets = {
            'description': forms.Textarea(attrs={'rows': 3}),
        }

class ProductForm(forms.ModelForm):
    class Meta:
        model = Product
        fields = ['name', 'code', 'price', 'stock', 'description', 'category', 'image']
        widgets = {
            'description': forms.Textarea(attrs={'rows': 3}),
            'price': forms.NumberInput(attrs={'step': '0.01'}),
        }

from django.views import View
from django.shortcuts import render, redirect, get_object_or_404
from django.core.paginator import Paginator, PageNotAnInteger, EmptyPage
from django.contrib import messages
from django.db.models import Q

class BaseCrudView(View):
    model = None
    form_class = None
    template_name = 'common/form.html'
    list_template_name = None
    print_template_name = 'common/print.html'
    base_list_template = 'common/base-list.html'
    success_url = None
    list_url = None
    title = None
    subtitle = None
    paginate_by = 10
    search_fields = ['name']

    def dispatch(self, request, *args, **kwargs):
        self.action = kwargs.pop('action', 'list')
        return super().dispatch(request, *args, **kwargs)

    def get(self, request, *args, **kwargs):
        if self.action == 'list':
            return self.list(request)
        elif self.action == 'create':
            return self.create_form(request)
        elif self.action == 'detail':
            return self.detail(request, kwargs.get('pk'))
        elif self.action == 'update':
            return self.update_form(request, kwargs.get('pk'))
        elif self.action == 'delete':
            return self.delete_confirm(request, kwargs.get('pk'))
        elif self.action == 'print':
            return self.print_view(request)
        return redirect(self.list_url)

    def post(self, request, *args, **kwargs):
        if self.action == 'create':
            return self.create_object(request)
        elif self.action == 'update':
            return self.update_object(request, kwargs.get('pk'))
        elif self.action == 'delete':
            return self.delete_object(request, kwargs.get('pk'))
        return redirect(self.list_url)

    def get_search_query(self, request):
        search_query = request.GET.get('search', '')
        if not search_query:
            return None
        q_objects = Q()
        for field in self.search_fields:
            q_objects |= Q(**{f"{field}__icontains": search_query})
        return q_objects

    def list(self, request):
        objects = self.model.objects.all()
        search_query = self.get_search_query(request)
        if search_query:
            objects = objects.filter(search_query)
        objects = self.apply_filters(request, objects)
        paginator = Paginator(objects, self.paginate_by)
        page = request.GET.get('page')
        try:
            objects = paginator.page(page)
        except PageNotAnInteger:
            objects = paginator.page(1)
        except EmptyPage:
            objects = paginator.page(paginator.num_pages)
        context = self.get_list_context(request, objects, paginator)
        return render(request, self.list_template_name, context)

    def apply_filters(self, request, queryset):
        return queryset

    def get_list_context(self, request, objects, paginator):
        return {
            'objects': objects,
            'model_name': self.model.__name__,
            'title': f"{self.title} List",
            'create_url': f"{self.list_url}create/",
            'list_url': self.list_url,
            'print_url': f"{self.list_url}print/",
            'is_paginated': objects.has_other_pages(),
            'paginator': paginator,
            'page_obj': objects,
            'request': request,
            'base_template': self.base_list_template,
        }

    def detail(self, request, pk):
        obj = get_object_or_404(self.model, pk=pk)
        form = self.form_class(instance=obj)
        context = {
            'form': form,
            'object': obj,
            'model_name': self.model.__name__,
            'title': f"View {self.title}",
            'subtitle': f"Details for {self.title.lower()}",
            'update_url': f"{self.list_url}{pk}/update/",
            'delete_url': f"{self.list_url}{pk}/delete/",
            'cancel_url': self.list_url,
            'is_detail_view': True,
            'is_disabled': True,
        }
        return render(request, self.template_name, context)

    def create_form(self, request):
        form = self.form_class()
        context = {
            'form': form,
            'title': f"Create {self.title}",
            'subtitle': f"Add a new {self.title.lower()}",
            'submit_text': 'Create',
            'cancel_url': self.list_url,
        }
        return render(request, self.template_name, context)

    def create_object(self, request):
        form = self.form_class(request.POST, request.FILES)
        if form.is_valid():
            obj = form.save()
            messages.success(request, f"{self.title} created successfully.")
            return redirect(self.success_url)
        context = {
            'form': form,
            'title': f"Create {self.title}",
            'subtitle': f"Add a new {self.title.lower()}",
            'submit_text': 'Create',
            'cancel_url': self.list_url,
        }
        return render(request, self.template_name, context)

    def update_form(self, request, pk):
        obj = get_object_or_404(self.model, pk=pk)
        form = self.form_class(instance=obj)
        context = {
            'form': form,
            'title': f"Update {self.title}",
            'subtitle': f"Modify {self.title.lower()} details",
            'submit_text': 'Update',
            'cancel_url': self.list_url,
        }
        return render(request, self.template_name, context)

    def update_object(self, request, pk):
        obj = get_object_or_404(self.model, pk=pk)
        form = self.form_class(request.POST, request.FILES, instance=obj)
        if form.is_valid():
            form.save()
            messages.success(request, f"{self.title} updated successfully.")
            return redirect(self.success_url)
        context = {
            'form': form,
            'title': f"Update {self.title}",
            'subtitle': f"Modify {self.title.lower()} details",
            'submit_text': 'Update',
            'cancel_url': self.list_url,
        }
        return render(request, self.template_name, context)

    def delete_confirm(self, request, pk):
        obj = get_object_or_404(self.model, pk=pk)
        context = {
            'object': obj,
            'title': f"Delete {self.title}",
            'subtitle': f"Are you sure you want to delete this {self.title.lower()}?",
            'cancel_url': self.list_url,
        }
        return render(request, 'common/delete_confirm.html', context)

    def delete_object(self, request, pk):
        obj = get_object_or_404(self.model, pk=pk)
        obj.delete()
        messages.success(request, f"{self.title} deleted successfully.")
        return redirect(self.list_url)

    def print_view(self, request):
        object_id = request.GET.get('id')
        if object_id:
            objects = self.model.objects.filter(pk=object_id)
        else:
            objects = self.model.objects.all()
        context = {
            'objects': objects,
            'model_name': self.model.__name__,
            'title': f"{self.title} Print View",
            'list_url': self.list_url,
        }
        return render(request, self.print_template_name, context)

from django.urls import reverse_lazy
from .models import Product, Category
from .forms import ProductForm, CategoryForm

class ProductView(BaseCrudView):
    model = Product
    form_class = ProductForm
    list_template_name = 'products/product_list.html'
    success_url = reverse_lazy('product-list')
    list_url = reverse_lazy('product-list')
    title = 'Product'
    search_fields = ['name', 'code', 'category__name']

    def apply_filters(self, request, queryset):
        category_id = request.GET.get('category')
        if category_id:
            queryset = queryset.filter(category_id=category_id)
        return queryset

    def get_list_context(self, request, objects, paginator):
        context = super().get_list_context(request, objects, paginator)
        context['categories'] = Category.objects.all()
        context['selected_category'] = request.GET.get('category', '')
        return context

class CategoryView(BaseCrudView):
    model = Category
    form_class = CategoryForm
    list_template_name = 'products/category_list.html'
    success_url = reverse_lazy('category-list')
    list_url = reverse_lazy('category-list')
    title = 'Category'
    search_fields = ['name']

from django.urls import path
from .views import ProductView, CategoryView

urlpatterns = [
    # Product URLs
    path('products/', ProductView.as_view(), name='product-list'),
    path('products/create/', ProductView.as_view(action='create'), name='product-create'),
    path('products/<int:pk>/', ProductView.as_view(action='detail'), name='product-detail'),
    path('products/<int:pk>/update/', ProductView.as_view(action='update'), name='product-update'),
    path('products/<int:pk>/delete/', ProductView.as_view(action='delete'), name='product-delete'),
    path('products/print/', ProductView.as_view(action='print'), name='product-print'),

    # Category URLs
    path('categories/', CategoryView.as_view(), name='category-list'),
    path('categories/create/', CategoryView.as_view(action='create'), name='category-create'),
    path('categories/<int:pk>/', CategoryView.as_view(action='detail'), name='category-detail'),
    path('categories/<int:pk>/update/', CategoryView.as_view(action='update'), name='category-update'),
    path('categories/<int:pk>/delete/', CategoryView.as_view(action='delete'), name='category-delete'),
    path('categories/print/', CategoryView.as_view(action='print'), name='category-print'),
]

from django.contrib import admin
from django.urls import path, include
from django.conf import settings
from django.conf.urls.static import static

urlpatterns = [
    path('admin/', admin.site.urls),
    path('', include('products.urls')),
]

if settings.DEBUG:
    urlpatterns += static(settings.MEDIA_URL, document_root=settings.MEDIA_ROOT)

templates/
    base.html
    common/
        base-list.html
        form.html
        delete_confirm.html
        print.html
    products/
        product_list.html
        category_list.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>{% block title %}Product Management System{% endblock %}</title>
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet">
    <style>
        body {
            padding-top: 20px;
        }
        .navbar {
            margin-bottom: 20px;
        }
    </style>
    {% block extra_css %}{% endblock %}
</head>
<body>
    <div class="container">
        <nav class="navbar navbar-expand-lg navbar-dark bg-primary rounded">
            <div class="container-fluid">
                <a class="navbar-brand" href="/">Product Management</a>
                <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarNav">
                    <span class="navbar-toggler-icon"></span>
                </button>
                <div class="collapse navbar-collapse" id="navbarNav">
                    <ul class="navbar-nav">
                        <li class="nav-item">
                            <a class="nav-link" href="{% url 'product-list' %}">Products</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link" href="{% url 'category-list' %}">Categories</a>
                        </li>
                    </ul>
                </div>
            </div>
        </nav>

        {% if messages %}
            <div class="messages">
                {% for message in messages %}
                    <div class="alert alert-{{ message.tags }}">
                        {{ message }}
                    </div>
                {% endfor %}
            </div>
        {% endif %}

        <div class="content mt-4">
            {% block content %}{% endblock %}
        </div>
    </div>

    <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/js/bootstrap.bundle.min.js"></script>
    {% block extra_js %}{% endblock %}
</body>
</html>

{% extends "base.html" %}

{% block content %}
<div class="card">
    <div class="card-header d-flex justify-content-between align-items-center">
        <h3>{{ title }}</h3>
        <a href="{{ create_url }}" class="btn btn-primary">Add New</a>
    </div>
    <div class="card-body">
        <div class="row mb-3">
            <div class="col-md-6">
                <form method="get" class="d-flex">
                    <input type="text" name="search" class="form-control me-2" placeholder="Search..." value="{{ request.GET.search|default:'' }}">
                    <button type="submit" class="btn btn-outline-primary">Search</button>
                </form>
            </div>
            <div class="col-md-6 text-end">
                <a href="{{ print_url }}" class="btn btn-outline-secondary" target="_blank">Print</a>
            </div>
        </div>

        {% block filters %}{% endblock %}

        {% block list_content %}{% endblock %}

        {% if is_paginated %}
        <nav aria-label="Page navigation">
            <ul class="pagination justify-content-center">
                {% if page_obj.has_previous %}
                <li class="page-item">
                    <a class="page-link" href="?page=1{% if request.GET.search %}&search={{ request.GET.search }}{% endif %}{% if request.GET.category %}&category={{ request.GET.category }}{% endif %}">« First</a>
                </li>
                <li class="page-item">
                    <a class="page-link" href="?page={{ page_obj.previous_page_number }}{% if request.GET.search %}&search={{ request.GET.search }}{% endif %}{% if request.GET.category %}&category={{ request.GET.category }}{% endif %}">Previous</a>
                </li>
                {% endif %}

                <li class="page-item disabled">
                    <span class="page-link">Page {{ page_obj.number }} of {{ paginator.num_pages }}</span>
                </li>

                {% if page_obj.has_next %}
                <li class="page-item">
                    <a class="page-link" href="?page={{ page_obj.next_page_number }}{% if request.GET.search %}&search={{ request.GET.search }}{% endif %}{% if request.GET.category %}&category={{ request.GET.category }}{% endif %}">Next</a>
                </li>
                <li class="page-item">
                    <a class="page-link" href="?page={{ paginator.num_pages }}{% if request.GET.search %}&search={{ request.GET.search }}{% endif %}{% if request.GET.category %}&category={{ request.GET.category }}{% endif %}">Last »</a>
                </li>
                {% endif %}
            </ul>
        </nav>
        {% endif %}
    </div>
</div>
{% endblock %}

{% extends "base.html" %}

{% block content %}
<div class="card">
    <div class="card-header">
        <h3>{{ title }}</h3>
        <p class="text-muted">{{ subtitle }}</p>
    </div>
    <div class="card-body">
        <form method="post" enctype="multipart/form-data">
            {% csrf_token %}

            {% for field in form %}
            <div class="mb-3">
                <label for="{{ field.id_for_label }}" class="form-label">{{ field.label }}</label>
                {% if is_disabled %}
                    {% if field.field.widget.input_type == 'file' and object.image %}
                        <div>
                            <img src="{{ object.image.url }}" alt="{{ object.name }}" style="max-width: 200px; max-height: 200px;">
                        </div>
                    {% else %}
                        <div class="form-control bg-light">{{ field.value|default:"-" }}</div>
                    {% endif %}
                {% else %}
                    {{ field.errors }}
                    {{ field }}
                {% endif %}
                {% if field.help_text %}
                <div class="form-text">{{ field.help_text }}</div>
                {% endif %}
            </div>
            {% endfor %}

            <div class="mt-4">
                {% if not is_detail_view %}
                <button type="submit" class="btn btn-primary">{{ submit_text|default:"Submit" }}</button>
                {% endif %}

                {% if is_detail_view %}
                <a href="{{ update_url }}" class="btn btn-primary">Edit</a>
                <a href="{{ delete_url }}" class="btn btn-danger">Delete</a>
                {% endif %}

                <a href="{{ cancel_url }}" class="btn btn-secondary">Back</a>
            </div>
        </form>
    </div>
</div>
{% endblock %}