switch dialect {
	case "mysql", "sqlserver":
		// these dialects do not support the "returning" clause
		return
	default:
		// This user struct will leverage the existing users table, but override
		// the Name field to default to null.
		type user struct {
			gorm.Model
			Name string `gorm:"default:null"`
		}
		u1 := user{}

		if results := DB.Create(&u1); results.Error != nil {

    public interface ContentTransformer {
        /**
         * Interpolate the value read from the xpp3 document
         * @param source The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                           log stuff.
         * @return The interpolated value.
         */
        String transform(String source, String fieldName);

	}

	stmt := dryDB.Clauses(clause.OrderBy{
		Expression: clause.Expr{SQL: "FIELD(id,?)", Vars: []interface{}{[]int{1, 2, 3}}, WithoutParentheses: true},
	}).Find(&User{}).Statement

	explainedSQL := dryDB.Dialector.Explain(stmt.SQL.String(), stmt.Vars...)
	if !regexp.MustCompile("SELECT \\* FROM .*users.* ORDER BY FIELD\\(id,1,2,3\\)").MatchString(explainedSQL) {
		t.Fatalf("Build Order condition, but got %v", explainedSQL)

* Puede hacer algo a esa **response** o ejecutar cualquier código necesario.
* Luego devuelve la **response**.

/// note | Detalles Técnicos

Si tienes dependencias con `yield`, el código de salida se ejecutará *después* del middleware.

  descriptor should declare whether it requires online/offline status.
  This value should be a java.lang.Boolean, so it can implement 3VL
  (three value logic: yes, no, don't-care). The requiresOnline
  field in the mojo descriptor has the following semantics:

  [true] Online status is required for this mojo to function
         correctly.

  [false] <<(Default)>> Either status is acceptable for the mojo to

    interface Transformer {
        /**
         * Interpolate the value read from the xml document
         *
         * @param source    The source value
         * @param fieldName A description of the field being interpolated. The implementation may use this to
         *                  log stuff.
         * @return the interpolated value
         */
        String transform(String source, String fieldName);
    }

{* ../../docs_src/dataclasses_/tutorial003_py310.py hl[1,4,7:10,13:16,22:24,27] *}

1. Мы по-прежнему импортируем `field` из стандартных `dataclasses`.

2. `pydantic.dataclasses` — полностью совместимая замена (drop-in replacement) для `dataclasses`.

3. Dataclass `Author` содержит список dataclass `Item`.

async def unrelated(foo: Annotated[str, object()]):
    return {"foo": foo}


client = TestClient(app)

foo_is_missing = {
    "detail": [
        {
            "loc": ["query", "foo"],
            "msg": "Field required",
            "type": "missing",
            "input": None,
        }
    ]
}
foo_is_short = {
    "detail": [
        {
            "ctx": {"min_length": 1},
            "loc": ["query", "foo"],

///

### Pydantic v1 and v2 on the same app { #pydantic-v1-and-v2-on-the-same-app }

It's **not supported** by Pydantic to have a model of Pydantic v2 with its own fields defined as Pydantic v1 models or vice versa.

```mermaid
graph TB
    subgraph "❌ Not Supported"
        direction TB
        subgraph V2["Pydantic v2 Model"]
            V1Field["Pydantic v1 Model"]
        end

{* ../../docs_src/dataclasses_/tutorial003_py310.py hl[1,4,7:10,13:16,22:24,27] *}

1. Wir importieren `field` weiterhin von Standard-`dataclasses`.

2. `pydantic.dataclasses` ist ein direkter Ersatz für `dataclasses`.

3. Die Datenklasse `Author` enthält eine Liste von `Item`-Datenklassen.