Many packages that simplify it a lot have to make many compromises with the data model, database, and available features. And some of these packages that simplify things too much actually have security flaws underneath.

---

**FastAPI** doesn't make any compromise with any database, data model or tool.

It gives you all the flexibility to choose the ones that fit your project the best.

//
// /////////////////////////////////////////////////////////////////////
func errExpressionTooLong(err error) *s3Error {
	return &s3Error{
		code:       "ExpressionTooLong",
		message:    "The SQL expression is too long: The maximum byte-length for the SQL expression is 256 KB.",
		statusCode: 400,
		cause:      err,
	}
}

func errColumnTooLong(err error) *s3Error {
	return &s3Error{
		code:       "ColumnTooLong",

They have proven to be **FastAPI Experts** by helping many others. ✨

/// tip

You could become an official FastAPI Expert too!

Just [help others with questions in GitHub](help-fastapi.md#help-others-with-questions-in-github){.internal-link target=_blank}. 🤓

///

You can see the **FastAPI Experts** for:

	defer w.m.Unlock()

	if w.nextOffset == offset {
		n, err = w.w.Write(b)
		w.nextOffset += int64(n)
	} else {
		if offset > w.nextOffset+ftpMaxWriteOffset {
			return 0, fmt.Errorf("write offset %d is too far ahead of next offset %d", offset, w.nextOffset)
		}
		w.buffer[offset] = make([]byte, len(b))
		copy(w.buffer[offset], b)
		n = len(b)
	}

again:
	nextOut, ok := w.buffer[w.nextOffset]
	if ok {

		HTTPStatusCode: http.StatusPreconditionFailed,
	},
	ErrRequestTimeTooSkewed: {
		Code:           "RequestTimeTooSkewed",
		Description:    "The difference between the request time and the server's time is too large.",
		HTTPStatusCode: http.StatusForbidden,
	},
	ErrSignatureDoesNotMatch: {
		Code:           "SignatureDoesNotMatch",

        <abbr title="Central Processing Unit">CPU</abbr>
        <abbr title="too long; didn't read"><strong>TL;DR:</strong></abbr>
        »»»

    Result (German):

        «««
        <abbr title="Internet of Things – Internet der Dinge">IoT</abbr>
        <abbr title="Central Processing Unit – Zentrale Verarbeitungseinheit">CPU</abbr>
        <abbr title="too long; didn't read – zu lang; hab's nicht gelesen"><strong>TL;DR:</strong></abbr>

```

</div>

Then go to the `/docs` UI, you will see that **FastAPI** is using these **models** to **document** the API, and it will use them to **serialize** and **validate** the data too.

<div class="screenshot">
<img src="/img/tutorial/sql-databases/image01.png">
</div>

## Update the App with Multiple Models { #update-the-app-with-multiple-models }

			objectName:     "foxdir/fooobject/foo.txt",
			objectModTime:  time.Now().UTC().Add(-10 * 24 * time.Hour), // Created 10 days ago
			expectedAction: DeleteAction,
		},
		// Too early to remove (test Days)
		{
			inputConfig:    `<LifecycleConfiguration><Rule><Filter><Prefix>foodir/</Prefix></Filter><Status>Enabled</Status><Expiration><Days>5</Days></Expiration></Rule></LifecycleConfiguration>`,

					// may synchronously trigger a Go event handler. This makes Go code get executed in the middle of the imported
					// function. A goroutine can switch to a new stack if the current stack is too small (see morestack function).
					// This changes the SP, thus we have to update the SP used by the imported function.

					// func wasmExit(code int32)
					"runtime.wasmExit": (sp) => {
						sp >>>= 0;

	// By default DB.DryRun should false
	if DB.DryRun {
		t.Fatal("Failed expect DB.DryRun to be false")
	}

	if DB.Dialector.Name() == "sqlserver" {
		t.Skip("Skip SQL Server for this test, because it too difference with other dialects.")
	}

	date, _ := time.ParseInLocation("2006-01-02", "2021-10-18", time.Local)

	// find
	sql := DB.ToSQL(func(tx *gorm.DB) *gorm.DB {