---
title: "Breaking: #75454 - TYPO3_db Constants removed"
manual: "TYPO3 Core Changelog"
version: "main"
permalink: "https://docs.typo3.org/permalink/changelog:breaking-75454-1668719172"
source: "Changelog/8.1/Breaking-75454-TYPO3_dbConstantsRemoved.rst"
modified: "2026-09-14T09:47:36+00:00"
---

# Breaking: #75454 - TYPO3_db Constants removed

See [forge#75454](https://forge.typo3.org/issues/75454)

## Description

The PHP constants `TYPO3_db`, `TYPO3_db_username`, `TYPO3_db_password` and `TYPO3_db_host`
which were used when TYPO3 initialized the database connection have been removed.

## Impact

Checking for or using the mentioned constants may lead to unexpected behavior or errors.
If not checked if the constant even was defined, the application will stop immediately.

## Affected Installations

Any installation which uses a third-party extension using these constants.

## Migration

Use the configuration data within `$GLOBALS['TYPO3_CONF_VARS']['DB']['Connections']['Default']`
to determine the username, password and host information for the default database connection.