```

</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>`,

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",

            userManual.getRoot().convention(extension.getSourceRoot().dir("userguide"));
            userManual.getStagingRoot().convention(extension.getStagingRoot().dir("usermanual"));
            // TODO: These should be generated too
            userManual.getSnippets().convention(layout.getProjectDirectory().dir("src/snippets"));
            userManual.getSamples().convention(layout.getProjectDirectory().dir("src/samples"));

   *   pinnedRoot (trusted by CertificatePinner)
   *     -> pinnedIntermediate (trusted by CertificatePinner)
   *         -> attackerSwitch
   * ```
   *
   * The attacker serves a set of certificates that yields a too-long chain in our certificate
   * pinner. The served certificates (incorrectly) formed a single chain to the pinner:
   *
   * ```
   *   attackerCa
   *     -> attackerIntermediate

 * }
 *
 * <h3>Comparison to alternatives</h3>
 *
 * <p><b>Note:</b> In some cases the differences explained below can be subtle. When it's unclear
 * which approach to use, <b>don't worry</b> too much about it; just pick something that seems
 * reasonable and it will be fine.
 *
 * <ul>
 *   <li>If checking whether the <i>caller</i> has violated your method or constructor's contract

    try {
      constructor = type.getConstructor();
    } catch (NoSuchMethodException e) {
      return arbitraryConstantInstanceOrNull(type);
    }
    constructor.setAccessible(true); // accessibility check is too slow
    try {
      return constructor.newInstance();
    } catch (InstantiationException | IllegalAccessException impossible) {
      throw new AssertionError(impossible);
    } catch (InvocationTargetException e) {

    assertThat((long) arraysDim1 * arraysDim2).isNotEqualTo((long) (arraysDim1 * arraysDim2));

    char[][] arrays = new char[arraysDim1][];
    // it's shared to avoid using too much memory in tests
    char[] sharedArray = new char[arraysDim2];
    Arrays.fill(arrays, sharedArray);

    try {
      Chars.concat(arrays);
      fail();
    } catch (IllegalArgumentException expected) {

* All these *path operations* will have the list of `dependencies` evaluated/executed before them.
    * If you also declare dependencies in a specific *path operation*, **they will be executed too**.
    * The router dependencies are executed first, then the [`dependencies` in the decorator](dependencies/dependencies-in-path-operation-decorators.md){.internal-link target=_blank}, and then the normal parameter dependencies.