Django Models: Purpose and Functionality
In Django, models represent the structure and behavior of data in a database. They define the fields and methods that a database table should have. Django follows the Object-Relational Mapping (ORM) pattern, which allows developers to interact with the database using high-level Python code instead of writing SQL queries directly.
To create a model in Django, you need to define a Python class that inherits from the django.db.models.Model class. Each attribute of the class represents a field of the model, and the field types determine the type of data that can be stored in the database. Django provides a wide range of field types, such as CharField, IntegerField, DateField, and ForeignKey, among others.
Example 1: Creating a simple model with a few fields
from django.db import models
class Customer(models.Model):
first_name = models.CharField(max_length=100)
last_name = models.CharField(max_length=100)
email = models.EmailField(unique=True)
date_of_birth = models.DateField()
In this example, we define a Customer model with four fields: first_name, last_name, email, and date_of_birth. The CharField and EmailField represent string fields, while the DateField represents a date field.
Example 2: Creating a model with a foreign key relationship
from django.db import models
class Order(models.Model):
customer = models.ForeignKey(Customer, on_delete=models.CASCADE)
product_name = models.CharField(max_length=100)
quantity = models.IntegerField()
price = models.DecimalField(max_digits=5, decimal_places=2)
In this example, we define an Order model that has a foreign key relationship with the Customer model. The ForeignKey field allows us to establish a one-to-many relationship between the Order and Customer models, where a customer can have multiple orders.
Django models also provide various methods and attributes to interact with the database. For example, you can use the objects attribute to query the database and retrieve instances of a model. Additionally, you can define custom methods on the model class to perform specific operations related to the data.
To use a model in Django, you need to register it in the Django admin interface, which allows you to perform CRUD (Create, Read, Update, Delete) operations on the data. The Django admin interface provides a useful and customizable interface for managing the data in your application.
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Additional Resources
– Django Admin Interface
– Custom Views in Django Admin
– Admin Actions in Django
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