Django at a glance

• it was designed to make common web development tasks fast and easy.

Design a model

• it comes with an object-relational mapper in which I describe database layout in Python code.
• The (data-model)[https://docs.djangoproject.com/en/4.0/topics/db/models/] syntax offers many rich ways of representing models.
• Note: when i create a model i dont have to provide an id because it will be handled
• example: ```python

from django.db import models

class Reporter(models.Model): full_name = models.CharField(max_length=70)

def __str__(self):
    return self.full_name

class Article(models.Model): pub_date = models.DateField() headline = models.CharField(max_length=200) content = models.TextField() reporter = models.ForeignKey(Reporter, on_delete=models.CASCADE)

def __str__(self):
    return self.headline

#### installing a model
```python
$ python manage.py makemigrations
$ python manage.py migrate

• The makemigrations command looks at all your available models and creates migrations for whichever tables don’t already exist.
• migrate runs the migrations and creates tables in your database, as well as optionally providing much richer schema control.

the database API and how to interact with db

• allow me to interact with database models.
• how to user it?
  1. import my models from news.models import Article, Reporter
  2. create object from model : ` report = Reporter(full_name=’John Smith’)`
  3. to save my object into db i have to call .save() method on my object: report.save()
  4. query the list of objects in that table: ModelName.objects.all() ```python Reporter.objects.all()

  <QuerySet [<Reporter: John Smith>]>. # result ``

  1. get object with specific id or value : ModelName.objects.get(columnName= Value) ```python Reporter.objects.get(id=1)

<QuerySet [<Reporter: John Smith>]>. # result

 6. starts with a value:
 ```python
 Reporter.objects.get(full_name__startswith='John')

1. contains a specefic value:

    Reporter.objects.get(full_name__startswith='John')
   

2. delete an object : objectName.delete()

dynamic admin interface

• when models are defined, Django can automatically create a professional, production ready administrative interface
• admin interface is website that lets authenticated users add, change and delete objects.
• The only step required is to register your model in the admin site.
• example: ```python website/news/model.py from django.db import models

class Article(models.Model): pub_date = models.DateField() headline = models.CharField(max_length=200) content = models.TextField() reporter = models.ForeignKey(Reporter, on_delete=models.CASCADE)

website/news/admin.py from django.contrib import admin

from . import models

admin.site.register(models.Article) # registering model to admin website

```

• The philosophy here is that the website is edited by a staff, or a client, or maybe just developer – and developer don’t want to have to deal with creating backend interfaces only to manage content.
• One typical workflow in creating Django apps is to create models and get the admin sites up and running as fast as possible, so your staff (or clients) can start populating data. Then, develop the way data is presented to the public.

Design URLs

• A clean, elegant URL scheme is an important detail in a high-quality web application.
• Django encourages beautiful URL design and doesn’t put any cruft in URLs, like .php or .asp.

how to create urls

• To design URLs for an app, create a Python module called a URLconf.
• A table of contents for the app, it contains a mapping between URL patterns and Python callback functions.
• URLconfs also serve to decouple URLs from Python code.
• Example of URLconf for the Reporter/Article example above: