Django ORM Ninja: Advanced Techniques for Developers

Django ORM Ninja: Advanced Techniques for Developers

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1. Introduction to Django ORM

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

Introduction to the Course

Introduction to the ORM

Start a New Project

Initialize a New Project

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

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. 🌟🔍💻🚀

Ordering and Slicing

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.

ForeignKey Arguments

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.

Field Lookups

Q and F Objects

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.

Transactions Basics

Conteúdo do Curso

Django ORM Ninja: Advanced Techniques for Developers

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 Lookups

A field lookup is essentially a way to specify how Django should filter query results based on a model field's value.

Basic Structure

A field lookup takes the form field__lookuptype=value. Here, field is the name of the model field, lookuptype is the type of comparison, and value is the value to compare against.

Common Field Lookups

exact - the default lookup type; it performs case-sensitive comparisons.
(SELECT * FROM Book WHERE genre = 'philosophy';)

iexact - case-insensitive match.
(SELECT * FROM Author WHERE LOWER(pen_name) = LOWER('george orwell');)

contains - case-sensitive containment test.
(SELECT * FROM Book WHERE title LIKE '%House%';)

icontains - case-insensitive containment test.
(SELECT * FROM Book WHERE LOWER(title) LIKE LOWER('%house%');)

in - in a given iterable; often used for filtering by a list of values.
(SELECT * FROM Author WHERE id IN (1, 4, 7);)

gt, gte, lt, lte - greater than, greater than or equal to, less than, and less than or equal to.
(SELECT * FROM Author WHERE id < 10;)

startswith, istartswith - string starts with a value (case-sensitive and insensitive versions).
(SELECT * FROM Author WHERE first_name LIKE 'J%';)

endswith, iendswith - string ends with a value (case-sensitive and insensitive versions).
(SELECT * FROM Author WHERE last_name LIKE '%e';)

range - within a certain range (inclusive).
(SELECT * FROM Book WHERE id BETWEEN 1 AND 5;)

date, year, month, day - specific date components.
(SELECT * FROM Book WHERE EXTRACT(YEAR FROM pub_date) = 2023;)

1. What is the default field lookup type in Django?

2. How do you filter a queryset to include records where the field value starts with a certain string, case-sensitively?

3. What does the lookup 'pk__lt=10' signify?

What is the default field lookup type in Django?

Selecione a resposta correta

contains

iexact

exact

in

How do you filter a queryset to include records where the field value starts with a certain string, case-sensitively?

Selecione a resposta correta

Model.objects.filter(field__endswith='value')

Model.objects.filter(field__startswith='value')

Model.objects.filter(field__istartswith='value')

Model.objects.filter(field__contains='value')

What does the lookup 'pk__lt=10' signify?

Selecione a resposta correta

Select records with a primary key less than or equal to 10.

Select records with a primary key greater than 10.

Select records with a primary key equal to 10.

Select records with a primary key less than 10.

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