Edit is broken because NULL values are handled incorrectly

Table has a column set as VARCHAR(1) & not required.

When trying to update the entry using CDBT, the update query sets the null/empty value to “NULL” a string of 4, which didn’t fit in the VARCHAR(1).

This caused the SQL to throw an error.

In the update_data() function I’ve updated:

 $data[$column]     = 'NULL';

To:

$data[$column]     = NULL;

And this has fixed the issue.