[TYPO3-dev] TCA select - Insert NULL

[Agash Thamo.]

Hello

I have made an extension for TYPO3 4.5 with extbase and fluid (i used Extension Builder). Now to insert some data, i use the backend module 'list', which generates some forms with the TCA of my table.
Now to make a select box optional, i insert an item with the value NULL before the foreign table, like this:

		'feuser' => array(
			'exclude' => 0,
			'label' => 'LLL:EXT:yes/Resources/Private/Language/locallang_db.xml:tx_yes_domain_model_schools.feuser',
			'config' => array(
				'type' => 'select',
				'items' => array(
					array('', NULL),
				),
				'foreign_table' => 'fe_users',
				'maxitems' => 1,
			),
		),

But it doesn't work. I get an SQL Error because of my relation (but NULL values are allowed). I also tried '', "" and 0. But those doesn't work either.

I would appreciate any help.

greeting
Agash Thamo.