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Tutorial: Create Django Models
===============================
Slide 1 [00:08 | 00:08]
-------------
Title Slide: ** Creating Django Models **
Slide 2 [00:13 | 00:21]
--------------
**Learning Objectives**
In this tutorial, we will learn to;
- Create a django model
- Database migration
- Use Admin app
Slide 3 [00:13 | 00:34]
---------------
**System Requirements**
- Ubuntu 16.10
- Python 3.5 or higher version
- python3.4-venv
Slide 4 [00:15 | 00:49]
---------------
**Pre-requisites**
In order to follow this tutorial, you need to know;
- how to create a django project
- If not, see the relevant django tutorial on http://spoken-tutorial.org
Slide 4: What is a Django Model [00:30 | 01:19]
--------------------------------------
- Every Django app has one or more models
- A Django model is a pythonic representation of a Database Table
- A Model Class represents a database table
- A Model attribute represents a column
- Each model instance is table row
- All django models are stored in a models.py
- models.py represents a Database
Slide 5: Creating Django Models for Blog app [00:35 | 01:54]
-----------------------------------------------
- We will create two tables 'blog' and 'article'
- The blog model will have 3 fields:
- name
- creator
- create_date
- the 'article' model will have 5 fields:
- blog
- title
- create_date
- author
- body
Demonstration [03:00 | 04:54]
----------------
- open */blog/models.py* in editor
- Type the following code
from django.db import models
class Blog(models.Model):
name = models.CharField(max_length=120)
created_on = models.DateTimeField('date created')
class Article(models.Model):
blog = models.ForeignKey(Blog, on_delete=models.CASCADE)
created_on = models.DateTimeField('date created')
title = models.CharField(max_length=120)
body = models.TextField()
draft = models.BooleanField(default=False)
- **(Not for narration) Note: For this demonstration there should explanation about each field **
Slide 6: What is a database migration [00:45| 05:39]
---------------------------------------
- A database migration is a technique that allows you to update your database, including
- Adding & Removing columns
- Altering columns (& the type of data that they can hold)
- Adding & Removing tables
- Migrations makes such changes easy since;
- No need to rebuild the database for every change
- Avoids loss of data
- Django handles migrations by creating a migration *.py* file
Demonstration [01:00| 06:39]
--------------------
- Run python manage.py --help
- Show the help text for *makemigrations* command
- Show the help text for *migrate* command
- Go to the directory containing *manage.py* file
- Make sure that the environment is active
- Run the command to create database migration files
- *python manage.py makemigrations*
- Run the command to apply these migrations
- *python manage.py migrate*
- Output:
- *Show command line output for makemigrations and migrate*
- Observe that a *db.sqlite3* has been created.
- Check the /blog/migrations/ directory and you will observe that a new file has been created.
Slide 5: What is Django Admin App [00:13| 06:52]
-------------------------------------------
- What is the Django Admin App
- The django admin app is a feature that provides an interface to Create, Read, Update and Delete model instances
Demonstration: Create a superuser [00:55| 07:47]
----------------------------------------------
- Create a superuser to login to the admin interface
- Run *python manage.py createsuperuser*
- Provide a username
- Provide an email address
- Provide a password and confirm it by entering again
- Output: *Superuser created successfully.*
Demonstration: Show the Admin interface [00:45| 08:32]
---------------------------------
- Run the django server with
- *python manage.py runserver*
- Open the web browser and go to http://127.0.0.1:8000/admin/
- You will see the login screen
- [Add Screenshot]
- Enter the superuser credentials as created previously
- You can see the interface
- [Add Screenshot]
Demonstration: Make the Blog App modifiable through Admin [00:45| 08:32]
-------------------------------------------
- In order to display the Blog app and it's components in the admin interface, change the */blog/admin.py* file;
# /blog/admin.py
from django.contrib import admin
from .models import Blog, Article
admin.site.register(Blog)
admin.site.register(Article)
- Save
- Login to the Admin interface
Demonstration: Add a Blog database entry [00:40| 09:12]
-----------------------
- Click on 'Blog'
- Click on 'Add Blog'
- Fill the form for new blog
- name
- creator
- create_date
- Click on Save
- You will see your new blog in the list
- You can click on the blog name to view it's details
- Click on Home (in breadcrumb section)
Demonstration: Add an Article database entry [00:45| 09:57]
--------------------------------
- Click on 'Article'
- Click on 'Add Article'
- Fill the form for the new Article
- blog: Select 'My New Blog' from list
- title
- create_date
- author: Select super-username form the list
- body: Add Article text
- Click on Save
- You will see your new article in the list
- You can click on the article name to view it's details
*** With this we come to the end of the tutorial***
----------------------------------------------------
*** Add concluding slides and assignment***
-------------------------------------------
|
