*/
@J2ktIncompatible
@GwtCompatible
/*
 * I have decided not to bother adding @ParametricNullness annotations in this class. Adding them is
 * a lot of busy work, and the annotation matters only when the APIs to be annotated are visible to
 * Kotlin code. In this class, nothing is publicly visible (nor exposed indirectly through a
 * publicly visible subclass), and I doubt any of our current or future Kotlin extensions for the

  /*
   * Preconditions.checkNotNull is *intended* for performing eager null checks on parameters that a
   * nullness checker can already "prove" are non-null. That means that the first parameter to
   * checkNotNull *should* be annotated to require it to be non-null.
   *
   * However, for a variety of reasons, Google developers have written a ton of code over the past

 */
@J2ktIncompatible
@GwtCompatible
/*
 * I have decided not to bother adding @ParametricNullness annotations in this class. Adding them is
 * a lot of busy work, and the annotation matters only when the APIs to be annotated are visible to
 * Kotlin code. In this class, nothing is publicly visible (nor exposed indirectly through a
 * publicly visible subclass), and I doubt any of our current or future Kotlin extensions for the

Vamos criar uma **dependência** do FastAPI com `yield` que fornecerá uma nova `Session` para cada requisição. Isso é o que garante que usamos uma única sessão por requisição. 🤓

Então, criamos uma dependência `Annotated` chamada `SessionDep` para simplificar o restante do código que usará essa dependência.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[25:30]  hl[25:27,30] *}

Мы создадим **зависимость** FastAPI с `yield`, которая будет предоставлять новую `Session` для каждого запроса. Это и обеспечивает использование одной сессии на запрос. 🤓

Затем мы создадим объявленную (`Annotated`) зависимость `SessionDep`, чтобы упростить остальной код, который будет использовать эту зависимость.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[25:30]  hl[25:27,30] *}

Crearemos una **dependencia de FastAPI** con `yield` que proporcionará una nueva `Session` para cada request. Esto es lo que asegura que usemos una sola session por request. 🤓

Luego creamos una dependencia `Annotated` `SessionDep` para simplificar el resto del código que usará esta dependencia.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[25:30]  hl[25:27,30] *}

Nous allons créer une **dépendance** FastAPI avec `yield` qui fournira une nouvelle `Session` pour chaque requête. C'est ce qui garantit que nous utilisons une seule session par requête. 🤓

Puis nous créons une dépendance `Annotated` `SessionDep` pour simplifier le reste du code qui utilisera cette dépendance.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[25:30]  hl[25:27,30] *}

**`Session`**은 **메모리에 객체**를 저장하고 데이터에 필요한 모든 변경 사항을 추적한 후, **`engine`을 통해** 데이터베이스와 통신합니다.

`yield`를 사용해 FastAPI의 **의존성**을 생성하여 각 요청마다 새로운 `Session`을 제공합니다. 이는 요청당 하나의 세션만 사용되도록 보장합니다. 🤓

그런 다음 이 의존성을 사용하는 나머지 코드를 간소화하기 위해 `Annotated` 의존성 `SessionDep`을 생성합니다.

{* ../../docs_src/sql_databases/tutorial001_an_py310.py ln[25:30]  hl[25:27,30] *}

### 시작 시 데이터베이스 테이블 생성하기 { #create-database-tables-on-startup }

애플리케이션 시작 시 데이터베이스 테이블을 생성합니다.

    for (Enumeration<?> e = properties.propertyNames(); e.hasMoreElements(); ) {
      /*
       * requireNonNull is safe because propertyNames contains only non-null elements.
       *
       * Accordingly, we have it annotated as returning `Enumeration<? extends Object>` in our
       * prototype checker's JDK. However, the checker still sees the return type as plain

    for (Enumeration<?> e = properties.propertyNames(); e.hasMoreElements(); ) {
      /*
       * requireNonNull is safe because propertyNames contains only non-null elements.
       *
       * Accordingly, we have it annotated as returning `Enumeration<? extends Object>` in our
       * prototype checker's JDK. However, the checker still sees the return type as plain