return items[item_id]


@app.patch("/items/{item_id}", response_model=Item)
async def update_item(item_id: str, item: Item):
    stored_item_data = items[item_id]
    stored_item_model = Item(**stored_item_data)
    update_data = item.dict(exclude_unset=True)
    updated_item = stored_item_model.copy(update=update_data)
    items[item_id] = jsonable_encoder(updated_item)

然后再用它生成一个只含已设置（在请求中所发送）数据，且省略了默认值的 `dict`：

```Python hl_lines="34"
{!../../../docs_src/body_updates/tutorial002.py!}
```

### 使用 Pydantic 的 `update` 参数

接下来，用 `.copy()` 为已有模型创建调用 `update` 参数的副本，该参数为包含更新数据的 `dict`。

例如，`stored_item_model.copy(update=update_data)`：

```Python hl_lines="35"
{!../../../docs_src/body_updates/tutorial002.py!}
```

### 更新部分数据小结

简而言之，更新部分数据应：

* 使用 `PATCH` 而不是 `PUT` （可选，也可以用 `PUT`）；
* 提取存储的数据；

```

We will use this model in our *path operation function*, so, we don't include in it the `hashed_password`.

### `UserInDB` model

Now, let's create a `UserInDB` model.

This will have the data that is actually stored in the database.

We don't create it as a subclass of Pydantic's `BaseModel` but as a subclass of our own `User`, because it will have all the attributes in `User` plus a couple more:

```Python hl_lines="31-33"

    return items[item_id]


@app.patch("/items/{item_id}", response_model=Item)
async def update_item(item_id: str, item: Item):
    stored_item_data = items[item_id]
    stored_item_model = Item(**stored_item_data)
    update_data = item.dict(exclude_unset=True)
    updated_item = stored_item_model.copy(update=update_data)
    items[item_id] = jsonable_encoder(updated_item)

* (Optionally) use `PATCH` instead of `PUT`.
* Retrieve the stored data.
* Put that data in a Pydantic model.
* Generate a `dict` without default values from the input model (using `exclude_unset`).
    * This way you can update only the values actually set by the user, instead of overriding values already stored with default values in your model.

    return items[item_id]


@app.patch("/items/{item_id}", response_model=Item)
async def update_item(item_id: str, item: Item):
    stored_item_data = items[item_id]
    stored_item_model = Item(**stored_item_data)
    update_data = item.dict(exclude_unset=True)
    updated_item = stored_item_model.copy(update=update_data)
    items[item_id] = jsonable_encoder(updated_item)

    ```

### Использование параметра `update` в Pydantic

Теперь можно создать копию существующей модели, используя `.copy()`, и передать параметр `update` с `dict`, содержащим данные для обновления.

Например, `stored_item_model.copy(update=update_data)`:

=== "Python 3.10+"

    ```Python hl_lines="33"
    {!> ../../../docs_src/body_updates/tutorial002_py310.py!}
    ```

=== "Python 3.9+"

    ```Python hl_lines="35"

    ```Python hl_lines="32"
    {!> ../../../docs_src/body_updates/tutorial002_py310.py!}
    ```

### ⚙️ Pydantic `update` 🔢

🔜, 👆 💪 ✍ 📁 ♻ 🏷 ⚙️ `.copy()`, & 🚶‍♀️ `update` 🔢 ⏮️ `dict` ⚗ 💽 ℹ.

💖 `stored_item_model.copy(update=update_data)`:

=== "🐍 3️⃣.6️⃣ & 🔛"

    ```Python hl_lines="35"
    {!> ../../../docs_src/body_updates/tutorial002.py!}
    ```

=== "🐍 3️⃣.9️⃣ & 🔛"

```Python hl_lines="34"
{!../../../docs_src/body_updates/tutorial002.py!}
```

### Pydanticの`update`パラメータ

ここで、`.copy()`を用いて既存のモデルのコピーを作成し、`update`パラメータに更新するデータを含む`dict`を渡すことができます。

`stored_item_model.copy(update=update_data)`のように:

```Python hl_lines="35"
{!../../../docs_src/body_updates/tutorial002.py!}
```

### 部分的更新のまとめ

まとめると、部分的な更新を適用するには、次のようにします:

* (オプションで)`PUT`の代わりに`PATCH`を使用します。

        run: bash scripts/test.sh
        env:
          COVERAGE_FILE: coverage/.coverage.${{ runner.os }}-py${{ matrix.python-version }}
          CONTEXT: ${{ runner.os }}-py${{ matrix.python-version }}
      - name: Store coverage files
        uses: actions/upload-artifact@v3
        with:
          name: coverage
          path: coverage

  coverage-combine:
    needs: [test]
    runs-on: ubuntu-latest
    steps: