=== "Python 3.9+"

    ```Python hl_lines="21-26  29-32  35-40  43-47  50-53"
    {!> ../../../docs_src/sql_databases/sql_app_py39/main.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="23-28  31-34  37-42  45-49  52-55"
    {!> ../../../docs_src/sql_databases/sql_app/main.py!}
    ```

我们在依赖项中的每个请求之前利用`yield`创建数据库会话，然后关闭它。

所以我们就可以在*路径操作函数*中创建需要的依赖，就能直接获取会话。

### ✍ 👆 **FastAPI** *➡ 🛠️*

🔜, 😒, 📥 🐩 **FastAPI** *➡ 🛠️* 📟.

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="23-28  31-34  37-42  45-49  52-55"
    {!> ../../../docs_src/sql_databases/sql_app/main.py!}
    ```

=== "🐍 3️⃣.9️⃣ & 🔛"

    ```Python hl_lines="21-26  29-32  35-40  43-47  50-53"

=== "Python 3.9+"

    ```Python hl_lines="21-26  29-32  35-40  43-47  50-53"
    {!> ../../../docs_src/sql_databases/sql_app_py39/main.py!}
    ```

=== "Python 3.8+"

    ```Python hl_lines="23-28  31-34  37-42  45-49  52-55"
    {!> ../../../docs_src/sql_databases/sql_app/main.py!}
    ```

We are creating the database session before each request in the dependency with `yield`, and then closing it afterwards.