DateTimeField – Django Models
In Django, DateTimeField is a field used to store a date and time, represented in Python by a datetime.datetime instance. It is mainly used to store an object of datetime created in Python. This article will provide an overview of DateTimeField, including its syntax, default form widget, and extra optional arguments.
Syntax of DateTimeField
In Django, DateTimeField can be defined using the following syntax:
field_name = models.DateTimeField(**options)Extra Optional Arguments
The DateTimeField in Django has two extra optional arguments that can be used to customize its functionality.
DateTimeField.auto_now
This argument automatically sets the field to the current date and time every time an object is saved, making it useful for “last-modified” timestamps. Note that the current date is always used; it’s not just a default value that can be overridden. The field is only automatically updated when calling Model.save(). If you make updates to other fields in other ways, such as QuerySet.update(), the field won’t be updated automatically. However, you can specify a custom value for the field in an update like that.
DateTimeField.auto_now_add
This argument automatically sets the field to the current date and time when the object is first created, making it useful for creation of timestamps. Note that the current date is always used; it’s not just a default value that can be overridden. So even if you set a value for this field when creating the object, it will be ignored. If you want to be able to modify this field, set the following instead of auto_now_add=True:
For DateTimeField: default=datetime.now – from datetime.now()
For DateTimeField: default=timezone.now – from django.utils.timezone.now()
Note that the options auto_now_add, auto_now, and default are mutually exclusive. Any combination of these options will result in an error.
Explanation of Django Model DateTimeField
To illustrate DateTimeField using an example, consider a project named geeksforgeeks with an app named geeks. Here’s how to create a DateTimeField in the GeeksModel model:
from django.db import models
from django.db.models import Modelgeeks_field =
models.DateTimeField()
Next, add the geeks app to INSTALLED_APPS:
INSTALLED_APPS = [ 'django.contrib.admin', 'django.contrib.auth', 'django.contrib.contenttypes', 'django.contrib.sessions', 'django.contrib.messages', 'django.contrib.staticfiles', 'geeks',]
When you run the makemigrations command from the terminal:
python manage.py makemigrations
A new folder named migrations will be created in the geeks directory with a file named 0001_initial.py. Then, run:
python manage.py migrate
This creates a geeks_field DateTimeField when you run migrations on the project. It is a field to store datetime.datetime Python objects.
How to Use DateTimeField
DateTimeField is used for storing Python datetime.datetime instances in the database. One can store any type of date and time using the same in the database. Let’s try storing a date in the model created above:
from geeks.models import GeeksModel
import datetimegeek_object = GeeksModel.objects.create(geeks_field = d)
geek_object.save()
After creating an instance of GeeksModel, let’s check it in the admin server.
Using DateTimeField in Django Admin
In Django, the admin interface is automatically generated from the installed apps’ models. This means that if a model has a DateTimeField, the admin interface will automatically display a user-friendly date and time picker. The Django admin also provides shortcuts for quickly adding or editing date and time values.
Using DateTimeField in Forms
In Django, a form is responsible for taking user input and validating it before saving it to the database. A DateTimeField in a form is rendered as a date and time picker widget, which allows users to select a date and time from a graphical interface. To use a DateTimeField in a form, you need to define a form class that inherits from Django’s built-in forms.Form class or a more specific form class, such as forms.ModelForm.
Here is an example of using a DateTimeField in a form:
from django import forms
class MyForm(forms.Form):
my_datetime_field = forms.DateTimeField(widget=forms.widgets.DateTimeInput(attrs={‘type’: ‘datetime-local’}))
DateTimeField is a fundamental data field in Django models that allows developers to store and manipulate date and time information in a relational database. This field is widely used in various types of applications, from simple blogs to complex financial systems. By utilizing the various field options and attributes, developers can customize the DateTimeField to suit their specific needs. The Django admin interface and form widgets make working with DateTimeField easy and intuitive for both developers and end-users.
Automatic DateTimeField
You can set the auto_now_add and auto_now arguments of the DateTimeField to True to automatically set the field to the current date and time when the model is first created and every time it is saved, respectively.
from django.db import models
class MyModel(models.Model):
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
# Other fields
Timezone-aware DateTimeField
If you want your DateTimeField to be timezone-aware, you can set the default argument to timezone.now, which returns the current date and time in the current timezone.
from django.db import models
from django.utils import timezonecreated_at = models.DateTimeField(default=timezone.now)
# Other fields
Custom DateTimeField Format
You can use the format argument of the DateTimeField to specify a custom format for the date and time string representation.
from django.db import models
class MyModel(models.Model):
created_at = models.DateTimeField(format=‘%Y-%m-%d %H:%M:%S’)
# Other fields
These are just a few examples of what you can do with DateTimeField in Django models. There are many other arguments and methods available that you can use to customize the behavior of your DateTimeField.
Field Options
Field Options are the arguments given to each field for applying some constraint or imparting a particular characteristic to a particular Field.
Field Options Description Null If True, Django will store empty values as NULL in the database. Default is False. Blank If True, the field is allowed to be blank. Default is False. db_column The name of the database column to use for this field. If this isn’t given, Django will use the field’s name. Default The default value for the field. This can be a value or a callable object. If callable it will be called every time a new object is created. help_text Extra “help” text to be displayed with the form widget. It’s useful for documentation purposes.
Here are the field options and attributes that a DateField can use.
| Field Options | Description |
|---|---|
| Null | If True, Django will store empty values as NULL in the database. Default is False. |
| Blank | If True, the field is allowed to be blank. Default is False. |
| db_column | The name of the database column to use for this field. If this isn’t given, Django will use the field’s name. |
| db_index | If True, a database index will be created for this field |
| db_tablespace | The name of the database tablespace to use for this field’s index, if this field is indexed. The default is the project’s DEFAULT_INDEX_TABLESPACE setting, if set, or the db_tablespace of the model, if any. If the backend doesn’t support tablespaces for indexes, this option is ignored. |
| Default | The default value for the field. This can be a value or a callable object. If callable it will be called every time a new object is created. |
| help_text | Extra “help” text to be displayed with the form widget. It’s useful for documentation even if your field isn’t used on a form. |
| primary_key | If True, this field is the primary key for the model. |
| editable | If False, the field will not be displayed in the admin or any other ModelForm. They are also skipped during model validation. Default is True. |
| error_messages | The error_messages argument lets you override the default messages that the field will raise. Pass in a dictionary with keys matching the error messages you want to override. |
| help_text | Extra “help” text to be displayed with the form widget. It’s useful for documentation even if your field isn’t used on a form. |
| verbose_name | A human-readable name for the field. If the verbose name isn’t given, Django will automatically create it using the field’s attribute name, converting underscores to spaces. |
| validators | A list of validators to run for this field. See the validators documentation for more information. |
| Unique | If True, this field must be unique throughout the table. |
Last Updated on April 16, 2023 by admin