DecimalField - Django Models - GeeksforGeeks

12 Feb, 2020
DecimalField is a field which stores a fixed-precision decimal number, represented in Python by a Decimal instance. It validates the input using DecimalValidator.
Syntax
field_name = models.DecimalField(max_digits=None, decimal_places=None, **options)
DecimalField.max_digitsThe maximum number of digits allowed in the number. Note that this number must be greater than or equal to decimal_places.
The maximum number of digits allowed in the number. Note that this number must be greater than or equal to decimal_places.
DecimalField.decimal_placesThe number of decimal places to store with the number.
The number of decimal places to store with the number.
For example, to store numbers up to 999 with a resolution of 2 decimal places, you’d use:
models.DecimalField(..., max_digits=5, decimal_places=2)
And to store numbers up to approximately one billion with a resolution of 10 decimal places:
models.DecimalField(..., max_digits=19, decimal_places=10)
Illustration of DecimalField using an Example. Consider a project named geeksforgeeks having an app named geeks.
Refer to the following articles to check how to create a project and an app in Django.
How to Create a Basic Project using MVT in Django?
How to Create an App in Django ?
Enter the following code into models.py file of geeks app.
from django.db import modelsfrom django.db.models import Model# Create your models here.  class GeeksModel(Model):    geeks_field = models.DecimalField(                         max_digits = 5,                         decimal_places = 2)
Add the geeks app to INSTALLED_APPS
# Application definition  INSTALLED_APPS = [    'django.contrib.admin',    'django.contrib.auth',    'django.contrib.contenttypes',    'django.contrib.sessions',    'django.contrib.messages',    'django.contrib.staticfiles',    'geeks',]
Now when we run makemigrations command from the terminal,
Python manage.py makemigrations
A new folder named migrations would be created in geeks directory with a file named 0001_initial.py
# Generated by Django 2.2.5 on 2019-09-25 06:00  from django.db import migrations, models  class Migration(migrations.Migration):      initial = True      dependencies = [    ]      operations = [        migrations.CreateModel(            name ='GeeksModel',            fields =[                ('id',                   models.AutoField(                  auto_created = True,                  primary_key = True,                  serialize = False,                   verbose_name ='ID'                )),                ('geeks_field', models.DecimalField(                                        max_digits = 5,                                        decimal_places = 2                )),            ],        ),    ]
Now run,
Python manage.py migrate
Thus, an geeks_field DecimalField is created when you run migrations on the project. It is a field to store datetime.date python object.
DecimalField is used for storing python datetime.date instance in the database. One can store any type of decimal number in the database. Let’s try storing a decimal number in the model created above.
# importing the model# from geeks appfrom geeks.models import GeeksModel  # importing datetime moduleimport decimal  # creating an instance of # datetime.dated = decimal.Decimal(9.53)  # creating an instance of # GeeksModelgeek_object = GeeksModel.objects.create(geeks_field = d)geek_object.save()
Now let’s check it in admin server. We have created an instance of GeeksModel.
Field Options are the arguments given to each field for applying some constraint or imparting a particular characteristic to a particular Field. For example, adding an argument null = True to DecimalField will enable it to store empty values for that table in relational database.Here are the field options and attributes that a DecimalField can use.
NaveenArora
Django-models
Python Django
Python
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