switch v := value.(type) {
		case []clause.Expression:
			for _, expr := range v {
				if eq, ok := expr.(clause.Eq); ok {
					switch column := eq.Column.(type) {
					case string:
						if field := db.Statement.Schema.LookUpField(column); field != nil {
							db.AddError(field.Set(db.Statement.Context, db.Statement.ReflectValue, eq.Value))
						}
					case clause.Column:

	// MetaSealedKeySSEC is the sealed object encryption key in case of SSE-C.
	MetaSealedKeySSEC = "X-Minio-Internal-Server-Side-Encryption-Sealed-Key"
	// MetaSealedKeyS3 is the sealed object encryption key in case of SSE-S3
	MetaSealedKeyS3 = "X-Minio-Internal-Server-Side-Encryption-S3-Sealed-Key"
	// MetaSealedKeyKMS is the sealed object encryption key in case of SSE-KMS

="";for(d=0;d<b.length;++d)if(b[d][0]===c){e=b[d][2];break}if(""===e)return!1;var f=e.match(/(.{3})/g).map(function(a){var b,c=a.slice(0,1),d=parseInt(a.slice(1),10);switch(c){case"A":b="0-9A-Za-z";break;case"B":b="0-9A-Z";break;case"C":b="A-Za-z";break;case"F":b="0-9";break;case"L":b="a-z";break;case"U":b="A-Z";break;case"W":b="0-9a-z"}return"(["+b+"]{"+d+"})"}),g=new RegExp("^"+f.join("")+"$");return a.length===b[d][1]&&g.test(a.slice(4))};a.formUtils.addValidator({name:"sepa",validatorFunctio...

{!> ../../docs_src/query_params/tutorial002_py310.py!}
```

////

//// tab | Python 3.8+

```Python hl_lines="9"
{!> ../../docs_src/query_params/tutorial002.py!}
```

////

In this case, the function parameter `q` will be optional, and will be `None` by default.

/// check

/// tip

**GraphQL** solves some very specific use cases.

It has **advantages** and **disadvantages** when compared to common **web APIs**.

Make sure you evaluate if the **benefits** for your use case compensate the **drawbacks**. 🤓

///

## GraphQL Libraries

Here are some of the **GraphQL** libraries that have **ASGI** support. You could use them with **FastAPI**:

## Use Case

Let's start with an example **use case** and then see how to solve it with this.

Let's imagine that you have some **machine learning models** that you want to use to handle requests. 🤖

func convPartErrToInt(err error) int {
	err = unwrapAll(err)
	switch err {
	case nil:
		return checkPartSuccess
	case errFileNotFound, errFileVersionNotFound:
		return checkPartFileNotFound
	case errFileCorrupt:
		return checkPartFileCorrupt
	case errVolumeNotFound:
		return checkPartVolumeNotFound
	case errDiskNotFound:
		return checkPartDiskNotFound
	default:
		return checkPartUnknown
	}
}

				continue
			}
		case data.FileAttributes&syscall.FILE_ATTRIBUTE_DIRECTORY != 0:
			name += SlashSeparator
		}

		count--
		entries = append(entries, name)

	}

	return entries, nil
}

func globalSync() {
	// no-op on windows
}

func syscallErrToFileErr(dirPath string, err error) error {
	switch err {
	case nil:
		return nil

type EncryptedString string

func (es *EncryptedString) Scan(ctx context.Context, field *schema.Field, dst reflect.Value, dbValue interface{}) (err error) {
	switch value := dbValue.(type) {
	case []byte:
		*es = EncryptedString(bytes.TrimPrefix(value, []byte("hello")))
	case string:
		*es = EncryptedString(strings.TrimPrefix(value, "hello"))
	default:
		return fmt.Errorf("unsupported data %#v", dbValue)
	}
	return nil
}

}

// Send a payload to the remote server.
func (s *Stream) Send(b []byte) error {
	if s.Requests == nil {
		return errors.New("stream does not accept requests")
	}
	select {
	case s.Requests <- b:
		return nil
	case <-s.ctx.Done():
		return context.Cause(s.ctx)
	}
}

// Results returns the results from the remote server one by one.
// If any error is returned by the callback, the stream will be canceled.