models.adoc

Django models

• 1. Override model save
• 2. Create a new model property
• 3. Create a new cached property in model
• 4. Use transaction.atomic to save model instance

1. Override model save

from django.db import models


class Author(models.Model):

    first_name = models.CharField(max_length=255)
    last_name = models.CharField(max_length=255)
    full_name = models.CharField(max_length=255)

    def __str__(self):
        return '{} - {}'.format(self.first_name, self.last_name)

    def save(self, *args, **kwargs):
        self.full_name = '{} {}'.format(self.first_name, self.last_name)
        super(Book).save(*args, **kwargs)

2. Create a new model property

from django.db import models


class Author(models.Model):

    first_name = models.CharField(max_length=255)
    last_name = models.CharField(max_length=255)

    def __str__(self):
        return '{} - {}'.format(self.first_name, self.last_name)

    def get_full_name(self):
        return '{} {}'.format(self.first_name, self.last_name)

3. Create a new cached property in model

from django.db import models
from django.utils.functional import cached_property


class Author(models.Model):

    first_name = models.CharField(max_length=255)
    last_name = models.CharField(max_length=255)

    def __str__(self):
        return '{} - {}'.format(self.first_name, self.last_name)

    @cached_property
    def get_full_name(self):
        return '{} {}'.format(self.first_name, self.last_name)

4. Use transaction.atomic to save model instance

from django.db import transaction


with transaction.atomic():
    book = Book(name='Introduction to Python')
    book.save()