Create number of fields based from choices - django

Question

*I'm trying to figure out how to populate fields in my model based on previous field selection.
For example, if FIELD_CHOICES = 3
Create 3x TextField()
class Post(models.Model):
STATUS_CHOICES = (('published','Published'),
('draft','Draft '))
FIELD_CHOICES = (('1','1 Title and body field'),
('2','2 Title and body fields'),
('3','3 Title and body fields'),
('4', '4 Title and body fields'),
('5', '5 Title and body fields'))
author = models.ForeignKey(User,
on_delete=models.CASCADE,
related_name='blog_post')
title = models.CharField(max_length=100)
sub_title = models.TextField(max_length=50,default="")
title_and_body_fields = models.IntegerField(choices=FIELD_CHOICES,
default=1)
**/// create number of title and body Textfields based on what was
/// selected in title_and_body_fields**
created = models.DateField()
publish = models.DateTimeField(default=timezone.now)
slug = models.SlugField(max_length=250,
unique_for_date='created')
status = models.CharField(max_length=250,
choices=STATUS_CHOICES,
default='draft')
object = models.Manager()
postManager = PostManager()
class Meta():
ordering = ('publish',)
def __strd__(self):
return self.title
def get_absolute_url(self):
return reverse('my_blog:post_detail',
args=[self.publish.year,
self.publish.month,
self.publish.day,
self.slug])
In the end i decided to do the following.
I added 5 seperate TextFields for Title and Body and added blank=True
title_5 = models.CharField(max_length=100,null=True,blank=True)
title_5_body = models.TextField(null=True,blank=True)

Answer 1

I'm afraid this is not possible.
I think you misunderstand how Models work. Have a look at the Django docs for models here.
Basically the way Django saves your models, is through an ORM (Object-Relational-Mapping).
This means that the model you write, with the fields contained within it, are transformed into a database query, generating a table.
In the docs for models, you can see this piece of code:
from django.db import models
class Person(models.Model):
first_name = models.CharField(max_length=30)
last_name = models.CharField(max_length=30)
is transformed to this SQL query:
CREATE TABLE myapp_person (
"id" serial NOT NULL PRIMARY KEY,
"first_name" varchar(30) NOT NULL,
"last_name" varchar(30) NOT NULL
);
This means that Django, under the hood, creates database tables for each Model you have in your app.
So how does work in Django?
Well, these SQL statements are generated when you run python manage.py makemigrations. The actual tables are created when you run python manage.py migrate.
This means that you only run these commands once (For every change to your model), and there will be only one table created for your model.
So why can't I add extra TextFields to an object?
This is because for each model there is only one table in the database, and your model would be stored like this:
id | first_name | last_name
----------------------------------
1 | John | Doe
2 | Jane | Doe
... | ... | ...
If you were to add an extra field (for instance phone_number) to John Doe, you'd need to add that field to the entire table.
So in your case, your choice is between no extra body and title fields, or a set amount extra fields for each object.
Ok, what now?
Well, there are a few ways to do this. Your best bet would be to create a ManyToMany relationship to a Model called something like PostBody, which would allow you to create an arbitrary amount of bodies for a set post.
You could modify the save method of you Post model to automatically create a set amount of PostBody objects for that object.
You can read read more about ManyToManyField here.