.. include:: /Includes.rst.txt .. _columns-link-properties-nullable: ======== nullable ======== .. versionchanged:: 12.0 This option was introduced to replace the TCA :php:`eval` option with :php:`null` as value. .. confval:: nullable :name: link-nullable :Path: $GLOBALS['TCA'][$table]['columns'][$field]['config'] :type: boolean :Default: false :Scope: Proc If set to true, a checkbox will appear, which by default deactivates the field. In the deactivated state the field is saved as :sql:`NULL` in the database. By activating the checkbox it is possible to set a value. If nothing is entered into the field, then an empty string will be saved and not a :sql:`NULL`. The database field must allow the :sql:`NULL` value. Example: .. code-block:: php :caption: EXT:some_extension/Configuration/TCA/tx_sometable.php 'columns' => [ 'nullable_column' => [ 'title' => 'A nullable field', 'config' => [ 'type' => 'link', 'nullable' => true, ], ], ],