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Django ORM Ninja: Técnicas Avanzadas para Desarrolladores
course content

Contenido del Curso

Django ORM Ninja: Técnicas Avanzadas para Desarrolladores

Django ORM Ninja: Técnicas Avanzadas para Desarrolladores

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

Ordering and Slicing

Slicing

Slicing, like Author.objects.all()[:1], retrieves a QuerySet limited to a specified range.

Remember that slicing on QuerySets, like [:1], is performed at the database level, so it's an efficient way to limit the number of results returned by a query.

Returns the first two objects (equivalent to LIMIT 2 in SQL).

Fetches the second and third objects from the table (akin to OFFSET 1 LIMIT 2 in SQL).

Ordering

To sort a QuerySet, use the order_by method with the attribute name for ordering. Prepend '-' for descending order.

For ascending order ( SELECT * FROM Author ORDER BY first_name;).

For descending order ( SELECT * FROM Author ORDER BY first_name DESC;).

To define multiple ordering criteria in one order_by statement:

(SELECT * FROM Author ORDER BY first_name ASC, last_name DESC;).

1. What does the Django query Author.objects.all()[:1] return?
2. How does Django perform slicing on QuerySets like [:1]?
3. What is the SQL equivalent of Author.objects.all()[:2]?
4. How do you sort a QuerySet in ascending order by the 'first_name' field?
5. Which Django query sorts authors first by ascending 'first_name' and then by descending 'last_name'?

What does the Django query Author.objects.all()[:1] return?

Selecciona la respuesta correcta

How does Django perform slicing on QuerySets like [:1]?

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What is the SQL equivalent of Author.objects.all()[:2]?

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How do you sort a QuerySet in ascending order by the 'first_name' field?

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Which Django query sorts authors first by ascending 'first_name' and then by descending 'last_name'?

Selecciona la respuesta correcta

¿Todo estuvo claro?

Sección 3. Capítulo 4
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