Traditional retrieval of objects is always as whole entities, i.e GetObject for a 5 GiB object, will always return 5 GiB of data. S3 Select API allows us to retrieve a subset of data by using simple SQL expressions. By using Select API to retrieve only the data needed by the application, drastic performance improvements can be achieved.

You can use the Select API to query objects with following features:

@GwtCompatible
public enum CollectionFeature implements Feature<Collection> {
  /**
   * The collection must not throw {@code NullPointerException} on calls such as {@code
   * contains(null)} or {@code remove(null)}, but instead must return a simple {@code false}.
   */
  ALLOWS_NULL_QUERIES,
  ALLOWS_NULL_VALUES(ALLOWS_NULL_QUERIES),

  /**
   * Indicates that a collection disallows certain elements (other than {@code null}, whose validity

import org.apache.maven.api.annotations.Nullable;

/**
 * Describes a problem that was encountered during project building. A problem can either be an exception that was
 * thrown or a simple string message. In addition, a problem carries a hint about its source.
 *
 * @since 4.0.0
 */
@Experimental
@Immutable
public interface BuilderProblem {

    /**

@GwtCompatible
public enum CollectionFeature implements Feature<Collection> {
  /**
   * The collection must not throw {@code NullPointerException} on calls such as {@code
   * contains(null)} or {@code remove(null)}, but instead must return a simple {@code false}.
   */
  ALLOWS_NULL_QUERIES,
  ALLOWS_NULL_VALUES(ALLOWS_NULL_QUERIES),

  /**
   * Indicates that a collection disallows certain elements (other than {@code null}, whose validity

{* ../../docs_src/body_nested_models/tutorial003_py310.py hl[12] *}

Com isso, mesmo que você receba uma requisição contendo dados duplicados, ela será convertida em um conjunto de itens exclusivos.

E sempre que você enviar esses dados como resposta, mesmo se a fonte tiver duplicatas, eles serão gerados como um conjunto de itens exclusivos.

E também teremos anotações/documentação em conformidade.

Die interaktive Dokumentation enthält also auch alle Informationen aus diesen Abhängigkeiten:

<img src="/img/tutorial/dependencies/image01.png">

## Einfache Verwendung { #simple-usage }

    * Will have the next best performance, after Uvicorn. In fact, Starlette uses Uvicorn to run. So, it probably can only get "slower" than Uvicorn by having to execute more code.
    * But it provides you the tools to build simple web applications, with routing based on paths, etc.
    * If you are comparing Starlette, compare it against Sanic, Flask, Django, etc. Web frameworks (or microframeworks).
* **FastAPI**:

They are, more or less, at opposite ends, complementing each other.

Requests has a very simple and intuitive design, it's very easy to use, with sensible defaults. But at the same time, it's very powerful and customizable.

That's why, as said in the official website:

> Requests is one of the most downloaded Python packages of all time

The way you use it is very simple. For example, to do a `GET` request, you would write:

```Python

        protected int readBytesWireFormat(byte[] buffer, int bufferIndex) throws SMBProtocolDecodingException {
            // Simple implementation for testing
            return 0;
        }

        @Override
        protected int writeBytesWireFormat(byte[] dst, int dstIndex) {
            // Simple implementation for testing
            return 0;
        }
    }

    @BeforeEach
    void setUp() {

### Usa el atributo `app.dependency_overrides` { #use-the-app-dependency-overrides-attribute }

Para estos casos, tu aplicación **FastAPI** tiene un atributo `app.dependency_overrides`, es un simple `dict`.

Para sobrescribir una dependencia para las pruebas, colocas como clave la dependencia original (una función), y como valor, tu dependencia para sobreescribir (otra función).