Metadata required fileds

Hello there

So, I'm having the following issue:

Repairing our customized installation of SugarCRM 11.0, I'm having several queries that returns errors.

I'm trying to fix those fields, in order to be able to have a clean repair, without Oracle giving us a bunch of errors while executing query.

We're using custom/metadata files in order to create custom tables that are used inside the Database and inside Sugar.

The question I have is the following: is there a safe way to create a field required or at least not nullable?

I'm having a long list of fields that returns ORA-01451 since the field in database is correctly defined as not nullable, but the repair asks Oracle to set this value to nullable.

So, my first guess was to add a 

'required' => true,

in the field creation:

$dictionary['my_table'] = array (
  'table' => 'my_table',
  'fields' =>
    array (
      0 =>
        array(
          'name' => 'my_field',
          'type' => 'varchar',
          'required' => true,
        ),
[...]

but what I got as suggested query during repair is this:

ALTER TABLE my_table MODIFY my_field varchar2(255)  NULL

Any ideas on how to do this? Is that something we can resolve?

TIA for any reply.