models.md

Models & Database

• Model - your database layout, with additional metadata.
  • Question - question and a publication date
  • Choice - has two fields: the text of the choice and a vote tally. A choice is correlated to a question

https://docs.djangoproject.com/en/3.2/intro/tutorial02/

Steps

1. Update polls/models.py to contain code bellow

# polls/models.py
import datetime
from django.db import models
from django.utils import timezone

class Question(models.Model):
    question_text = models.CharField(max_length=200)
    pub_date = models.DateTimeField('date published')
    def __str__(self):
        return self.question_text

    def was_published_recently(self):
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1)

class Choice(models.Model):
    question = models.ForeignKey(Question, on_delete=models.CASCADE)
    choice_text = models.CharField(max_length=200)
    votes = models.IntegerField(default=0)
    def __str__(self):
        return self.choice_text

2. Update INSTALLED_APPS in mysite/settings.py to contain 'polls.apps.PollsConfig'

3. Update polls code in manage.py - python3.9 manage.py makemigrations polls

# expected output
Migrations for 'polls':
  polls/migrations/0001_initial.py
    - Create model Question
    - Create model Choice

4. Update database as a result of the migration in step 3 - cd $HOME/mysite2 ; python3.9 manage.py sqlmigrate polls 0001

5. Repeat step 3 (python3.9 manage.py makemigrations polls) to attach the created tables

API

0. Assert that the web application is running - cd $HOME/mysite2 ; python3.9 manage.py runserver

1. Access the API interface - python3.9 manage.py shell

2. Create a new question (based on polls/models.py) and save in the database

from polls.models import Choice, Question
from django.utils import timezone

# create a new question
q = Question(question_text="What's new?", pub_date=timezone.now())

# save question
q.save()

# view all questions 
Question.objects.all()