A Slug is basically a short label for something, containing only letters, numbers, underscores or hyphens. They’re generally used in URLs. For example, in a typical blog entry URL:
https://www.geeksforgeeks.org/add-the-slug-field-inside-django-model/
Here, the last data add-the-slug-field-inside-django-model
is the slug.
SlugField :
SlugField in Django is like a CharField, where you can specify max_length
attribute also. If max_length is not specified, Django will use a default length of 50. It also implies setting Field.db_index to True.It is often useful to automatically prepopulate a SlugField based on the value of some other value.It uses validate_slug or validate_unicode_slug for validation.
Syntax
field_name = models.SlugField(max_length=200, **options)
SlugField has following optional arguments:
SlugField.max_length
The maximum length (in characters) of the field. The max_length
is enforced at the database level and in Django’s validation using MaxLengthValidator.
SlugField.allow_unicode
If True, the field accepts Unicode letters in addition to ASCII letters. Defaults to False.
Django Model SlugField Explanation
Illustration of SlugField using an Example. Consider a project named neveropen
having an app named Lazyroar
.
Refer to the following articles to check how to create a project and an app in Django.
Enter the following code into models.py
file of Lazyroar app.
from django.db import models from django.db.models import Model # Create your models here. class GeeksModel(Model): Lazyroar_field = models.SlugField(max_length = 200 ) |
Add the Lazyroar 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' , 'Lazyroar' , ] |
Now when we run makemigrations
command from the terminal,
Python manage.py makemigrations
A new folder named migrations would be created in Lazyroar
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' )), ( 'Lazyroar_field' , models.SlugField( max_length = 200 , )), ], ), ] |
Now run,
Python manage.py migrate
Thus, an Lazyroar_field
SlugField is created when you run migrations on the project.
How to use SlugField ?
SlugField is used for storing basically storing URL paths after a particular URL. To know more about how to properly add a SlugField to Django Project, refer this article – Add the slug field inside Django Model
# importing the model # from Lazyroar app from Lazyroar.models import GeeksModel # creating a instance of # GeeksModel geek_object = GeeksModel.objects.create(Lazyroar_field = "") geek_object.save() |
Now let’s check it in admin server. We have created an instance of GeeksModel.
Field Options
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 SlugField will enable it to store empty values for that table in relational database.
Here are the field options and attributes that an SlugField 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. |
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. |
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