Django is a high-level Python Web framework that encourages rapid
development and clean, pragmatic design.
Model: The application data
View: which data is presented
Template: How the data is presented
A project is just a collection of settings organized in a defined folder
structure to run an instance of Django and they can be auto generated using a
Django-admin command offered by the Django package.
The Django development server: python manage.py runserver
The server runs by default on port 8000 and on the default local host IP
127.0.0.01. you can change this by passing the port as the first argument of
the runserver command.
Each one of the Django apps included by default needs at least one
database table that will be created when we run a Django management command
called syncdb.
A Django app is just a Python package with a certain structure located
somewhere in your Python path.
The models essentially represented the database layout with some
additional metadata.
The first thing that you should note is that each model is represented by
a class that is a subclass of Django.db.models.Model. the class
variables in the models represent the database field.
Each field is an istance of the Field class and tells Django what kind of
data each field holds. Each field type can be easily understood by looking at
the class names.
The name of each field instance is the name that you will use in your
Python code to reference the field as well as the column name in your
database.
Syncdb command an be called as many times as you like, it will only create
the tables that do not exist in the database.
In Django, a view is just a Python function that accepts a request
object as the first parameter and returns a valid HttpResponse Object.
When a Django page is requested the engine looks at the ROOT_URLCONF
variable in the settings.py file to know which module is responsible for the
routing in this module. Django expects to find a variable called urlpatterns,
which is a sequence of tuples with following format: (regular expression,
Python callback function [, optional directory])
Django starts matching the requested URL against each regular expression
in the list, and as soon as it finds one that matches it calls the callback
Python function by passing an HttpRequest object as the first argument.
HttpRequest.method: A string representing the HTTP method used in the
request. This is guaranteed to be uppercase.
HttpRequest.GET: a dictionary-like object containing all given HTTP GET
parameters
HttpRequest.POST: a dictionary-like object containing all given HTTP POST
parameters
HttpRequest.META: a standard dictionary Python dictionary containing all
available HTTP headers.
HttpRequest.user: A Django.contrib.auth.models.User object representing
the currently logged-in user. If the user isn‘t currently logged in, the user
object will be set to an instance of
Django.contrib.auth.models.AnonymousUser
HttpRequest.session: a readable-and-writable dictionary-like object that
represents the current session. This is only available if your Django
installation has session support activated.
