Search and ordering in Django - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to filter books with a title containing 'django'.

Django

books = Book.objects.filter(title__[1]='django')

Drag options to blanks, or click blank then click option'

Aicontains

Bcontains

Cstartswith

Dexact

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'contains' which is case-sensitive and may miss matches.

Using 'exact' which looks for an exact match, not substring.

The icontains lookup filters case-insensitively for the substring 'django' in the title.

2fill in blank

medium

Complete the code to order books by their publication date descending.

Django

books = Book.objects.order_by('[1]')

Drag options to blanks, or click blank then click option'

A-date_published

B-publication_date

Cdate_published

Dpublication_date

Attempts:

3 left

💡 Hint

Common Mistakes

Ordering ascending by missing the minus sign.

Using a wrong field name that does not exist.

Prefixing the field name with a minus sign - orders descending.

3fill in blank

hard

Fix the error in the code to search books by author name case-insensitively.

Django

books = Book.objects.filter(author__[1]='john doe')

Drag options to blanks, or click blank then click option'

Acontains

Bstartswith

Ciexact

Dicontains

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'contains' which is case-sensitive.

Using 'iexact' which requires full exact match.

icontains allows case-insensitive substring matching, suitable for searching names.

4fill in blank

hard

Fill both blanks to filter books published after 2020 and order by title ascending.

Django

books = Book.objects.filter(publication_year__[1]=2020).order_by('[2]')

Drag options to blanks, or click blank then click option'

Agt

Blt

Ctitle

D-title

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'lt' which filters before 2020.

Ordering by '-title' which sorts descending.

gt means greater than, so books after 2020 are filtered. Ordering by title sorts ascending.

5fill in blank

hard

Fill all three blanks to create a dictionary of book titles and authors for books with rating above 4, ordered by rating descending.

Django

result = {book.[1]: book.[2] for book in Book.objects.filter(rating__[3]=4).order_by('-rating')}

Drag options to blanks, or click blank then click option'

Atitle

Bauthor

Cgt

Drating

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'rating' or 'author' as dictionary keys incorrectly.

Using 'lt' or 'gte' instead of 'gt' for filtering.

We use title as keys and author as values. The filter uses gt to get ratings above 4. Ordering by -rating sorts descending.

Practice

1. What is the main purpose of adding search and ordering features in a Django ListView?

easy

A. To change the database schema automatically

B. To speed up the server response time

C. To disable pagination on the page

D. To let users find and sort data easily

Solution

1. Step 1: Understand the role of search and ordering

   Search and ordering help users locate specific data and arrange it in a preferred sequence.

2. Step 2: Identify the main benefit in a ListView context

   In Django ListView, these features improve user experience by making data easier to find and view in order.

3. Final Answer:

   To let users find and sort data easily -> Option D

4. Quick Check:

   Search and ordering = user-friendly data access [OK]

Hint: Search and ordering improve user data access quickly [OK]

Common Mistakes:

• Thinking search changes database structure
• Assuming ordering disables pagination
• Believing it speeds server without code changes

2. Which of the following is the correct way to override the get_queryset method in a Django ListView to add ordering by a field named name?

easy

A. def get_queryset(self): return self.queryset.order_by('name')

B. def get_queryset(self): return super().get_queryset().order_by('name')

C. def get_queryset(self): return self.objects.order_by('name')

D. def get_queryset(self): return Model.objects.order_by('name')

Solution

1. Step 1: Recall how to override get_queryset in ListView

   Use super() to get the base queryset, then apply ordering.

2. Step 2: Check each option for correct syntax and context

   def get_queryset(self): return super().get_queryset().order_by('name') correctly calls super() and orders by 'name'. Others misuse queryset or model references.

3. Final Answer:

   def get_queryset(self): return super().get_queryset().order_by('name') -> Option B

4. Quick Check:

   Use super() + order_by() = def get_queryset(self): return super().get_queryset().order_by('name') [OK]

Hint: Use super() to get base queryset before ordering [OK]

Common Mistakes:

• Using self.queryset without defining it
• Calling objects on self instead of model
• Not using super() in get_queryset override

3. Given this Django ListView code snippet, what will be the result of accessing the view with URL parameter ?search=apple&order=price?

class ProductListView(ListView):
    model = Product
    def get_queryset(self):
        qs = super().get_queryset()
        search = self.request.GET.get('search')
        order = self.request.GET.get('order')
        if search:
            qs = qs.filter(name__icontains=search)
        if order:
            qs = qs.order_by(order)
        return qs

medium

A. Products filtered to names containing 'apple' and ordered by price

B. All products ordered by price ignoring search

C. Products filtered by price containing 'apple'

D. Error because 'order' parameter is not validated

Solution

1. Step 1: Analyze filtering by 'search' parameter

   The code filters products where name contains 'apple' (case-insensitive).

2. Step 2: Analyze ordering by 'order' parameter

   The code orders the filtered queryset by the 'price' field.

3. Final Answer:

   Products filtered to names containing 'apple' and ordered by price -> Option A

4. Quick Check:

   Filter by search + order by price = Products filtered to names containing 'apple' and ordered by price [OK]

Hint: Filter first, then order queryset in get_queryset [OK]

Common Mistakes:

• Ignoring the search filter when order is present
• Confusing filter field with order field
• Assuming error without validation in this context

4. Identify the error in this Django ListView code that tries to add search and ordering:

class ItemListView(ListView):
    model = Item
    def get_queryset(self):
        qs = super().get_queryset()
        search = self.request.GET.get('search')
        if search:
            qs = qs.filter(name__icontains=search)
        order = self.request.GET.get('order')
        qs = qs.order_by(order)
        return qs

medium

A. Missing pagination in the view

B. Using filter with icontains instead of contains

C. Calling order_by without checking if 'order' is None

D. Not calling super() in get_queryset

Solution

1. Step 1: Check usage of order_by with 'order' parameter

   The code calls order_by(order) without verifying if order is None, causing error if no 'order' param.

2. Step 2: Verify other parts for correctness

   Filter with icontains is valid, super() is called, pagination is optional and not an error here.

3. Final Answer:

   Calling order_by without checking if 'order' is None -> Option C

4. Quick Check:

   order_by needs valid field or check [OK]

Hint: Check if order param exists before calling order_by [OK]

Common Mistakes:

• Assuming filter icontains is wrong
• Forgetting to call super() (not the case here)
• Confusing pagination with query errors

5. You want to implement a Django ListView that allows users to search products by name and order results by price or rating. You also want to prevent invalid ordering fields from causing errors. Which is the best way to implement get_queryset?

hard

A. Filter by search term, then order only if order param is in allowed list ['price', 'rating']

B. Filter by search term, order by any order param without validation

C. Order first by order param, then filter by search term

D. Ignore search and order, just return all products

Solution

1. Step 1: Understand the need for validation of ordering fields

   Allowing only specific fields prevents errors and security issues.

2. Step 2: Apply filtering before ordering and validate order param

   Filter products by search term, then order only if order param is in ['price', 'rating'].

3. Final Answer:

   Filter by search term, then order only if order param is in allowed list ['price', 'rating'] -> Option A

4. Quick Check:

   Validate order param before ordering = Filter by search term, then order only if order param is in allowed list ['price', 'rating'] [OK]

Hint: Validate order fields before ordering queryset [OK]

Common Mistakes:

• Ordering without checking allowed fields
• Ordering before filtering
• Ignoring search parameter completely