{Name: "OwnerID", DBName: "company_owner_id", BindNames: []string{"Base", "OwnerID"}, DataType: schema.Int, Size: 64, TagSettings: map[string]string{"EMBEDDED": "EMBEDDED", "EMBEDDEDPREFIX": "company_"}},
		{Name: "OwnerID", DBName: "owner_id", BindNames: []string{"CorpBase", "OwnerID"}, DataType: schema.String},
	}

	for _, f := range fields {

For example, if you have an app like this:

```Python
from fastapi import FastAPI
from pydantic import BaseModel

class Item(BaseModel):
    name: str
    price: Optional[float] = None
    owner_ids: Optional[List[int]] = None

app = FastAPI()

@app.get("/items/invalidnone", response_model=Item)
def get_invalid_none():
    return None
```

`item.dict()`

 & ⤴️ 👥 🚶‍♀️ `dict`'Ⓜ 🔑-💲 👫 🇨🇻 ❌ 🇸🇲 `Item`, ⏮️:

`Item(**item.dict())`

 & ⤴️ 👥 🚶‍♀️ ➕ 🇨🇻 ❌ `owner_id` 👈 🚫 🚚 Pydantic *🏷*, ⏮️:

`Item(**item.dict(), owner_id=user_id)`

///

## 👑 **FastAPI** 📱

& 🔜 📁 `sql_app/main.py` ➡️ 🛠️ & ⚙️ 🌐 🎏 🍕 👥 ✍ ⏭.

### ✍ 💽 🏓

📶 🙃 🌌 ✍ 💽 🏓:

func TestJoinsPreload_Issue7013_RelationEmpty(t *testing.T) {
	type (
		Furniture struct {
			gorm.Model
			OwnerID *uint
		}

		Owner struct {
			gorm.Model
			Furnitures []Furniture
			CompanyID  *uint
			Company    Company
		}

		Building struct {
			gorm.Model
			Name    string
			OwnerID *uint
			Owner   Owner
		}
	)

	DB.Migrator().DropTable(&Building{}, &Owner{}, &Furniture{})

这里不是将每个关键字参数传递给Item并从Pydantic模型中读取每个参数，而是先生成一个字典，其中包含Pydantic模型的数据：

`item.dict()`

然后我们将dict的键值对 作为关键字参数传递给 SQLAlchemy `Item`：

`Item(**item.dict())`

然后我们传递 Pydantic模型未提供的额外关键字参数`owner_id`：

`Item(**item.dict(), owner_id=user_id)`

///

## 主**FastAPI**应用程序

现在在`sql_app/main.py`文件中 让我们集成和使用我们之前创建的所有其他部分。

### 创建数据库表

以非常简单的方式创建数据库表：

//// tab | Python 3.9+

//
//	type User struct {
//	  Toys []Toy `gorm:"polymorphic:Owner;"`
//	}
//	type Pet struct {
//	  Toy Toy `gorm:"polymorphic:Owner;"`
//	}
//	type Toy struct {
//	  OwnerID   int
//	  OwnerType string
//	}
func (schema *Schema) buildPolymorphicRelation(relation *Relationship, field *Field) {
	polymorphic := field.TagSettings["POLYMORPHIC"]

	relation.Polymorphic = &Polymorphic{