PERKS ABOUT DJANGO

WHAT IS DJANGO?

• Django is a high level Python Web framework that encourages rapid development and clean, pragmatic design.
• It is a free and open source web application framework.

WHERE DID DJANGO COME FROM?

• It is developed from a online news operation.
• It’s primary goal is to “ease the creation of complex, database-driven websites”
• It lets you built high performing, elegant web applications quickly.
• Written in Python, 2005.

COOL DJANGO FEATURES:

• Adheres to the DRY principle.
• Emphasizes re-usability.
• Focuses on automating as much as possible.
• Provides an optional admin account.
• Object Relational Mapper (ORM)
• Automatic admin interface.
• Elegant URL design.
• Cache system.
• Internationalization.

COMPANIES WHICH USE DJANGO:

• Pinterest
• Instagram
• Mozilla Foundation
• The Washington Foundation
• Disqus
• Public Broadcasting Services(PBS)
• OpenStack

DJANGO’S ORM:

Object relational mapping:

A model is the single, definitive source of information about your data. It contains the essential fields and behaviors of the data you are storing. Generally, each model maps to a single database table.

The basics:

• Each model is a Python class that subclasses django.db.models.Model
• Each attribute of the model represents a database field.
• With all of this, Django gives you an automatically generated database-access API.

from django.db import models

class Person(models.Model):

    first_name=models.CharField(max_length=30)

    last_name=models.CharField(max_length=30)

Equivalent table created in SQL:

CREATE TABLE myapp_person(

    “id” seriel NOT NULL PRIMARY KEY,

    “first_name” varchar(30) NOT NULL,

    “last_name” varchar(30) NOT NULL

);

DJANGO’S ADMIN INTERFACE:

As simple as configuring your settings, and creating a user:

• Python manage .py createsuperuser
• Fill in user name and password.
• And then go to your _domain/admin.

DJANGO’S TEMPLATE LANGUAGE:

1. Templates

• Simply a text file
• Contains variables and tags.
• base.html

2. Variables

• {{variable}}
• Evaluates variable and replaces with replaces with result.
• Alphanumeric characters and underscore only.
• Dot notation to access attributes of a variable.

3. Filters

• Modify variables for display by using filters.
• Apply filters with a pipe (|), filters can be chained.
• Examples: {{list|join:”,”}} , {{value|length}} , {{value|striptags}} , {{name|lower}}

4. Tags

• Create text in the output, load external information
• Control flow, loops or logic.
• for, if elif else, block and extends.

5. Comments

6. Template Inheritance

• {% extends “base.html” %}
• {% block content %} Content here {% endblock %}

DJANGO VS FLASK:

• Not a fair comparison, depends on what you want to do with either of them.
• Flask is simpler, Django more complicated.
• Flask has less built-in stuff, Django has more features ans is more powerful and robust.
• Flask is pure Python, Django has it’s own ‘pseudo’ language.
• Flask is easy to get started. Django requires a little learning before starting.

TIP OF THE DAY:

• Django is awesome!!!
• ORM can help save time and makes CRUD operations a lot nicer and easier.
• Admin account makes interacting with the page content super simple.
• Template language makes working with models and page content easier and more integrated, template tags and logic make HTML less ugly.
• Great documentation, easy to learn, and makes web development faster and easier for most people.