This documentation is not using the current rendering mechanism and is probably outdated. The extension maintainer should switch to the new system. Details on how to use the rendering mechanism can be found here.
Viewing cached database information¶
The DBAL extension makes heavy use of caching for field information. This includes primary keys, auto_increment fields and native/meta types of fields.
To see the cached data select View cached data in the DBAL Debug backend module. From there you can clear the cache file, if that seems necessary (it is automatically cleaned whenever the database structure is changed from within TYPO3).