A **One-to-One** relationship is used when one object of a model corresponds to exactly one object of another model. For example, a table of employees and another table of employee ID badges, where each employee has exactly one unique ID badge. To specify a **One-to-One** relation, use `models.OneToOneField`.
``` python
id_badge = models.OneToOneField(IdBadge, on_delete=models.CASCADE, related_name=employee).
```
**OneToOneField** accepts all of the extra arguments accepted by **ForeignKey**.

There is just example of usage **One-to-One** relations. We will not use it in our project. 

``` python
from django.db import models

class Employee(models.Model):
    name = models.CharField(max_length=100)
    position = models.CharField(max_length=100)

class Badge(models.Model):
    employee = models.OneToOneField(Employee, on_delete=models.CASCADE, related_name='badge')
    badge_number = models.CharField(max_length=50)
    issue_date = models.DateField()

employee = Employee.objects.get(name='Jane Doe')
employee_badge = employee.badge  # Accessing Badge through Employee instance

badge = Badge.objects.get(badge_number='123456789')
employee = badge.employee  # Accessing Employee from Badge instance
```

You can learn more about this relation in the <a 
href="https://docs.djangoproject.com/en/4.2/ref/models/fields/#onetoonefield"
target="_blank"
style="color: #ff8a00; font-weight: 600; text-decoration: none; transition: 0.3s ease-in-out;"
onmouseover="this.style.color='#ff0000'"
onmouseout="this.style.color='#d27204'">official documentation</a>.

How can you access the related Badge object from an Employee instance named employee?

Aprende a construir aplicaciones utilizando el framework Django ORM. Este es el siguiente paso en la expansión de su conocimiento del desarrollo de Django.

A quick overview of the Django ORM. One of the advantages of Django is the Django ORM.

You will learn about Django's robust modeling system, including field data types for precise database structuring. The section also covers migrations for seamless schema updates and the powerful admin interface, providing an intuitive way to manage your application's data.

This essential section is your treasure map for navigating Create, Read, Update, and Delete (CRUD) operations. Effortlessly craft queries to add new records, fetch and explore data with finesse, seamlessly update existing records, and confidently delete what's no longer needed. Each example is a key, unlocking the power and elegance of Django ORM. 🌟🔍💻🚀

Explore the intricate world of database relationships in Django! This section delves into the core concepts of Many-to-One, One-to-One, and Many-to-Many relationships. Learn how to effectively model real-world scenarios in your database using Django's powerful ORM, with clear examples and practical use-cases to guide you.

After this section, you will be able to master Django's field lookups, Q and F objects for advanced queries, and Aggregation and Annotation for data summarization. You'll also learn techniques to minimize database hits, addressing the N+1 problem, and effectively using select and prefetch related.

This section delves into advanced Django concepts, including the Meta class for model customization, the implementation of constraints for data integrity, the basics of transactions for ensuring database consistency, and an overview of the User model, a core component for handling user authentication and permissions in Django applications.

Django ORM Ninja: Técnicas Avanzadas para Desarrolladores

One-to-One