cusUser := CustomizeUser{
			Name: "update-has-one-associations",
			Account: CustomizeAccount{
				Number:  number,
				Number2: number,
			},
		}

		if err := DB.Create(&cusUser).Error; err != nil {
			t.Fatalf("errors happened when create: %v", err)
		}
		cusUser.Account.Number += "-update"
		cusUser.Account.Number2 += "-update"

### Pydantic의 `update` 파라미터 사용하기 { #using-pydantics-update-parameter }

이제 `.model_copy()`를 사용해 기존 모델의 복사본을 만들고, 업데이트할 데이터가 들어있는 `dict`를 `update` 파라미터로 전달할 수 있습니다.

예: `stored_item_model.model_copy(update=update_data)`:

{* ../../docs_src/body_updates/tutorial002_py310.py hl[33] *}

### 부분 업데이트 요약 { #partial-updates-recap }

정리하면, 부분 업데이트를 적용하려면 다음을 수행합니다:

// NewFromFunc allocates a new cached value instance and initializes it with an
// update function, making it ready for use.
func NewFromFunc[T any](ttl time.Duration, opts Opts, update func(ctx context.Context) (T, error)) *Cache[T] {
	return &Cache[T]{
		ttl:      ttl,
		updateFn: update,
		opts:     opts,
	}
}

// InitOnce initializes the cache with a TTL and an update function. It is
// guaranteed to be called only once.

  private @Nullable ByteBuffer scratch;

  /** Updates this hasher with the given byte. */
  protected abstract void update(byte b);

  /** Updates this hasher with the given bytes. */
  protected void update(byte[] b) {
    update(b, 0, b.length);
  }

  /** Updates this hasher with {@code len} bytes starting at {@code off} in the given buffer. */
  protected void update(byte[] b, int off, int len) {

      return listenersUpdater.getAndSet(future, update);
    }

    @Override
    @Nullable Waiter gasWaiters(AbstractFutureState<?> future, Waiter update) {
      return waitersUpdater.getAndSet(future, update);
    }

    @Override
    boolean casValue(AbstractFutureState<?> future, @Nullable Object expect, Object update) {
      return valueUpdater.compareAndSet(future, expect, update);
    }

	if err != nil {
		t.Fatalf("Set Update with multiple associations failed: %v", err)
	}
	// Only association operations were executed; no row update is expected
	if rows != 0 {
		t.Fatalf("expected 0 rows affected for association-only update, got %d", rows)
	}

	// Verify both associations were updated using real database queries
	var updatedUser User

        for (int i = key.length; i < 64; i++) {
            ipad[i] = 0x36;
            opad[i] = 0x5c;
        }

        md5.update(ipad);
        md5.update(data);
        byte[] innerHash = md5.digest();

        md5.reset();
        md5.update(opad);
        md5.update(innerHash);
        byte[] expected = md5.digest();

        try (MockedStatic<Crypto> mockedCrypto = mockStatic(Crypto.class)) {

            Hexdump.hexdump(log, input, offset, Math.min(len, 256));
            log.flush();
        }
        if (len == 0) {
            return; /* CRITICAL */
        }
        digest.update(input, offset, len);
        updates++;
    }

    /**
     * Computes and returns the message digest.
     *
     * @return the computed digest bytes
     */

)

func TestUpdateHasManyAssociations(t *testing.T) {
	user := *GetUser("update-has-many", Config{})

	if err := DB.Create(&user).Error; err != nil {
		t.Fatalf("errors happened when create: %v", err)
	}

	user.Pets = []*Pet{{Name: "pet1"}, {Name: "pet2"}}
	if err := DB.Save(&user).Error; err != nil {
		t.Fatalf("errors happened when update: %v", err)
	}

	var user2 User
	DB.Preload("Pets").Find(&user2, "id = ?", user.ID)

	user := *GetUser("update-belongs-to", Config{})

	if err := DB.Create(&user).Error; err != nil {
		t.Fatalf("errors happened when create: %v", err)
	}

	user.Company = Company{Name: "company-belongs-to-association"}
	user.Manager = &User{Name: "manager-belongs-to-association"}
	if err := DB.Save(&user).Error; err != nil {
		t.Fatalf("errors happened when update: %v", err)
	}

	var user2 User