---
title: "Breaking: #80929 - TYPO3_DB moved to extension"
manual: "TYPO3 Core Changelog"
version: "main"
permalink: "https://docs.typo3.org/permalink/changelog:breaking-80929"
source: "Changelog/9.0/Breaking-80929-TYPO3_DBMovedToExtension.rst"
typo3-version: "9.0"
typo3-major: 9
type: "breaking"
issue: 80929
forge: "https://forge.typo3.org/issues/80929"
tags: ["Database", "PHP-API", "FullyScanned"]
rendered: "2026-09-18T17:00:34+00:00"
---

# Breaking: #80929 - TYPO3_DB moved to extension {#breaking-80929}

See [forge#80929](https://forge.typo3.org/issues/80929)

## Description {#description}

The legacy class `DatabaseConnection` better known as `$GLOBALS['TYPO3_DB']` has been moved
to the new system extension ext:typo3db_legacy.

The following classes have been moved and renamed, including an alias to the original class name:

-   `\TYPO3\CMS\Core\Database\DatabaseConnection` to `\TYPO3\CMS\Typo3DbLegacy\Database\DatabaseConnection`
-   `\TYPO3\CMS\Core\Database\PreparedStatement` to `\TYPO3\CMS\Typo3DbLegacy\Database\PreparedStatement`
-   `\TYPO3\CMS\Core\Database\PostProcessQueryHookInterface` to `\TYPO3\CMS\Typo3DbLegacy\Database\PostProcessQueryHookInterface`
-   `\TYPO3\CMS\Core\Database\PreProcessQueryHookInterface` to `\TYPO3\CMS\Typo3DbLegacy\Database\PreProcessQueryHookInterface`

## Impact {#impact}

`$GLOBALS['TYPO3_DB']` is no longer initialized by the core bootstrap. Third party extensions
that rely on `$GLOBALS['TYPO3_DB']` will trigger a fatal error if `ext:typo3db_legacy`
is not loaded.

## Affected Installations {#affected-installations}

Installations with extensions which did not migrate to doctrine yet and need `$GLOBALS['TYPO3_DB']`.

## Migration {#migration}

[Migrate affected extensions to doctrine](https://docs.typo3.org/typo3cms/CoreApiReference/ApiOverview/Database/Migration/Index.html)
or load extension `typo3db_legacy` as backwards compatible layer to `$GLOBALS['TYPO3_DB']`
(the extension is available via TER and may be installed from there or directly
via the upgrade wizard `typo3DbLegacyExtension`).