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Django ORM Ninja: Advanced Techniques for Developers

Many-to-ManyMany-to-Many

A Many-to-Many relationship occurs when each record in a model can be associated with many records in another model, and vice versa. This is facilitated by Django's models.ManyToManyField.

Let's explore the ManyToManyField with an example. In our project, we use two models: Author and Book. An author can write multiple books, and a book might be co-authored by multiple authors. This is a classic many-to-many relationship.

Let's implement it in our code. In the models.py add to the Book model a new field.

Accessing Related Records

From Author to Books:

From Book to Authors:

Adding and Removing Relationships

Adding an author to a book:

Removing an author from a book:

Filtering with ManyToManyField

You can also filter queries based on Many-to-Many relationships. For example, to find all books co-authored by a specific author:

1. How can you access all books written by an author named 'Richard Bachman'?
2. What Django query is used to add an author to a book?
3. How can you find all books co-authored by 'Richard Bachman'?

question-icon

How can you access all books written by an author named 'Richard Bachman'?

Select a few correct answers

What Django query is used to add an author to a book?

Select the correct answer

How can you find all books co-authored by 'Richard Bachman'?

Select the correct answer

Everything was clear?

Section 4. Chapter 4
course content

Course Content

Django ORM Ninja: Advanced Techniques for Developers

1. Introduction to Django ORM

Introduction to the CourseIntroduction to the ORMStart a New ProjectInitialize a New Project

2. Models, datatypes, and fields

Defining The First ModelField Data TypesDefine Other ModelsMigrationsAdmin Interface

3. Queries

Create QueryRetrieve QueryLazy QueriesOrdering and SlicingUpdatingDeleting

4. Relations

Many-to-OneForeignKey ArgumentsOne-to-OneMany-to-Many

5. Complex Queries

Field LookupsQ and F ObjectsAggregationsAnnotationsMinimazing Database Hints

6. Advanced

Class MetaConstrainsTransactions BasicsUser Model

Django ORM Ninja: Advanced Techniques for Developers

Many-to-ManyMany-to-Many

A Many-to-Many relationship occurs when each record in a model can be associated with many records in another model, and vice versa. This is facilitated by Django's models.ManyToManyField.

Let's explore the ManyToManyField with an example. In our project, we use two models: Author and Book. An author can write multiple books, and a book might be co-authored by multiple authors. This is a classic many-to-many relationship.

Let's implement it in our code. In the models.py add to the Book model a new field.

Accessing Related Records

From Author to Books:

From Book to Authors:

Adding and Removing Relationships

Adding an author to a book:

Removing an author from a book:

Filtering with ManyToManyField

You can also filter queries based on Many-to-Many relationships. For example, to find all books co-authored by a specific author:

1. How can you access all books written by an author named 'Richard Bachman'?
2. What Django query is used to add an author to a book?
3. How can you find all books co-authored by 'Richard Bachman'?

question-icon

How can you access all books written by an author named 'Richard Bachman'?

Select a few correct answers

What Django query is used to add an author to a book?

Select the correct answer

How can you find all books co-authored by 'Richard Bachman'?

Select the correct answer

Everything was clear?

Section 4. Chapter 4
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