Contenido del Curso
Django ORM Ninja: Técnicas Avanzadas para Desarrolladores
Django ORM Ninja: Técnicas Avanzadas para Desarrolladores
1. Introduction to Django ORM
2. Models, datatypes, and fields
Annotations
Annotation in Django ORM allows you to attach additional information to each object in a QuerySet. It's a powerful feature for augmenting the results of queries with calculated values, which can be aggregates computed over related objects or values derived from model fields.
Basic Annotation
Example 1:
Assume each Book has a pages
field.
This annotates each genre with the total number of pages of all books within that genre.
Example 2:
Assume each Book has a rating
field.
Adds an average rating for the books written by each author.
Advanced Annotation Use Cases
Example 1:
Assume each Book has a publication_date
field.
Counts how many books each author published per year.
Example 2:
Finds the most recently published book for each genre.
Annotation with Filters
Example 1:
Counts the number of fantasy books written by each author.
¿Todo estuvo claro?