Django ORM Ninja: Advanced Techniques for Developers

1. Introduction to Django ORM

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

2. Models, datatypes, and fields

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.

Defining The First Model

Field Data Types

Define Other Models

Migrations

Admin Interface

3. Queries

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. 🌟🔍💻🚀

4. Relations

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.

5. Complex Queries

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.

Minimazing Database Hints

6. Advanced

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.

Conteúdo do Curso

Django ORM Ninja: Advanced Techniques for Developers

1. Introduction to Django ORM

Introduction to the Course Introduction to the ORM Start a New Project Initialize a New Project

2. Models, datatypes, and fields

Defining The First Model Field Data Types Define Other Models Migrations Admin Interface

3. Queries

Create Query Retrieve Query Lazy Queries Ordering and Slicing Updating Deleting

4. Relations

Many-to-One ForeignKey Arguments One-to-One Many-to-Many

5. Complex Queries

Field Lookups Q and F Objects Aggregations Annotations Minimazing Database Hints

6. Advanced

Class Meta Constrains Transactions Basics User Model

Field Data Types

In this chapter, we will consider the most useful data types for fields, with other types described in the official documentation.

Field data type	Python type	Description
CharField	str	Text-based values
IntegerField	int	Positive and negative integer field
TextField	str	A large text field without any limitations in character number.
DecimalField	float (decimal)	It is a fixed-precision decimal number. More precise than just float numbers in Python. This field typically includes parameters like max_digits and decimal_places
DateField	date	A date, presented as datetime.date instance in Python
DateTimeField	datetime	A date and time, presented as datetime.datetime instance in Python
EmailField	str	String that checks that value is a valid email address.
ImageField	...	Validates that the uploaded object is a valid image.

The most common field options are:

max_length (it is the required argument for the CharField field);
null (if True, it will be possible to store empty values as NULL. Default is False);
blank (if True, the field is allowed to be blank. Default is False);
default (You can pass the default value for the field. For example, often used date_created = models.DateTimeField(default=datetime.utcnow()) the current time will be stored as a value);
primary_key (usually used for the id field);
unique (if True, this field must be unique throughout the table. Useful for nickname field, for example);
choices (the default form widget will be a select box instead of a standard text field and will limit choices).

Here is an example of how to use the choices field:

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Seção 2. Capítulo 2