Django

Question 1

What is Models?

Answer 1

Deals with data and databases, it can retrieve, store, and change data in a database.

Question 2

What is Templates?

Answer 2

Determines how the data looks on a web page.

Question 3

What is Views?

Answer 3

Describes the data to be presented, and passes this information to the template.

Question 4

How to start Django project?

Answer 4

django-admin <command></command> [options]
django-admin startproject projectname

Question 5

What are apps in Django?

Answer 5

a Django app is a submodule to a project, that contains the code for a specific feature.
- To add a new app, run this command in the root folder: python3 manage.py startapp vetoffice
- When adding a new app, you must add it to the INSTALLED_APPS under settings.py

Question 6

What are projects in Django?

Answer 6

A Django project refers to the entire code base and its parts.

Question 7

What is the folder structure for a Django app?

Answer 7

projectname/
|– appname/
|– templates/
|– appname/
|– file.html
|– static/
|– appname/
|– file.css

Question 8

What is DTL?

Answer 8

Django Template Language. Allows you to write django/python expressions within html document. Can be used to display variables, loops, and create conditionals.
You can also use filters to modify the data so that you dont have to write much more code.

Question 9

What are some drawbacks to preinstalled SQLite?

Answer 9

SQLite’s signature portability unfortunately makes it a poor choice when many different users are updating the table at the same time (to maintain integrity of data, only one user can write to the file at a time). It also may require some more work to ensure the security of private data due to the same features that make SQLite accessible. Furthermore, SQLite does not offer the same exact functionality as many other database systems, limiting some advanced features other relational database systems offer. Lastly, SQLite does not validate data types. Many other database software would reject data that does not conform to a table’s schema, how a table’s data is organized. However, SQLite allows users to store data of any type into any column.

Question 10

What is the difference between null and blank?

Answer 10

null is a field can be left intentionally void of information. blank is similar to null, but setting blank to True means a field doesn’t have to take anything, not even a null value.

Question 11

What are methods in models?

Answer 11

Methods are functions defined in our model that describe the behaviors and actions of our model.

Question 12

What are migrations? When is it necessary? How do you make migrations?

Answer 12

Migrations are Django’s way of propagating changes you make to your models (adding a field, deleting a model, etc.) into your database schema.
Migrations are needed when we make changes to our models.

1. Running python3 manage.py makemigrations to create a file with the instructions needed for our database to create the proper schemas.
2. Running python3 manage.py migrate to execute the instructions in our file to create the actual tables in our database.

Question 13

How to reverse a migration?

Answer 13

python3 manage.py migrate <app_name> <migration_name>
migration_name would be something like 0001 or 0002
Use python3 manage.py showmigrations <app_name> to see a list of all the migrations.</app_name></migration_name></app_name>

Question 14

How to get data from database using Django shell?

Answer 14

ModelName.objects.get(name=”name”)

Question 15

How to delete data from database using Django shell?

Answer 15

ModelName.objects.first().delete()

Question 16

What is the exclude querying method?

Answer 16

Returns objects that do not match the argument

Question 17

What is the order_by querying method?

Answer 17

Returns objects in ascending or descending (-) order that match the argument

Question 18

How to query two tables at once?

Answer 18

Using the filter() method

Question 19

What does the view do in Django?

Answer 19

A view is a function that takes in an HTTP request and returns an HTTP response.

Question 20

What is generic view?

Answer 20

They take certain common idioms and patterns found in view development and abstract them so that you can quickly write common views of data without having to write too much code.

Question 21

Explain CRUD operations in generic view

Answer 21

Import the generic views below:

from django.shortcuts import render
from .models import Owner, Patient
from django.views.generic import ListView
from django.views.generic.edit import CreateView, UpdateView, DeleteView

def home(request):
context = {“name”: “Djangoer”}
return render(request, “vetoffice/home.html”, context)

class OwnerList(ListView):
model = Owner
template_name = “vetoffice/owner_list.html”

class PatientList(ListView):
model = Patient
template_name = “vetoffice/patient_list.html”

Create your other generic views below:
class OwnerCreate(CreateView):
model = Owner
template_name = “vetoffice/owner_create_form.html”
fields = [“first_name”, “last_name”, “phone”]

class PatientCreate(CreateView):
model = Patient
template_name = “vetoffice/patient_create_form.html”
fields = [“animal_type”, “breed”, “pet_name”, “age”, “owner”]

class OwnerUpdate(UpdateView):
model = Owner
template_name = “vetoffice/owner_update_form.html”
fields = [“first_name”, “last_name”, “phone”]

class PatientUpdate(UpdateView):
model = Patient
template_name = “vetoffice/patient_update_form.html”
fields = [“animal_type”, “breed”, “pet_name”, “age”, “owner”]

class OwnerDelete(DeleteView):
model = Owner
template_name = “vetoffice/owner_delete_form.html”

class PatientDelete(DeleteView):
model = Patient
template_name = “vetoffice/patient_delete_form.html”

Inside the view.py file, you need to define paths for each crud operations!

Question 22

What does Http404() do?

Answer 22

show 404 page if the request object does not exist. Use try, except blocks

Question 23

What is CSRF token?

Answer 23

Cross Site Request Forgery protection. The CSRF middleware and template tag provides easy-to-use protection against Cross Site Request Forgeries. This type of attack occurs when a malicious website contains a link, a form button or some JavaScript that is intended to perform some action on your website, using the credentials of a logged-in user who visits the malicious site in their browser. A related type of attack, ‘login CSRF’, where an attacking site tricks a user’s browser into logging into a site with someone else’s credentials, is also covered.

The CSRF token protects the application and the user by adding a secret token inside of the “POST” methods in the forms each time the form is rendered. The CSRF token ensures that only the proper user is using the proper credentials.

Question 24

What is get_absolute_path method?

Answer 24

Redirects user to another page after submitting data.