Overview

The Django web framework includes a default object-relational mapping layer (ORM) for interacting with data from relational databases such as SQLite, PostgreSQL, and MySQL. It is an API that Django uses and allows us to add, delete, and modify a query object. ORM stands for Object Relational Mapping. An object-relational mapper bridges the gap between relational databases and object-oriented programming languages without the need for SQL queries.

Introduction

You must have come across a situation where you have to find the total price of the materials you purchased. Similarly, when a group of records or a query set is defined, a summary of all these items is required. Well, aggregating and annotating objects refers to summing up or putting together the values. Annotation of an object creates a separate summary for each object in a queryset. Aggregation of an object is to generate summary values over an entire QuerySet.