TCA

The folder EXT:my_extension/Configuration/TCA/ may contain or override TCA (TYPO3 configuration array) data.

All files in this directory are automatically included during the TYPO3 bootstrap.

<tablename>.php

One file per database table, using the name of the table for the file, plus ".php". Only for new tables.

Overrides

For extending existing tables.

General advice: One file per database table, using the name of the table for the file, plus .php. For more information, see the chapter Extending the TCA array.