Help:Fixed properties/Fixed property handling
This page explains on how to handle fixed properties from a technical perspective. It obviously still needs to be expanded further.
The name of the database table is formed using md5 from SMW 1.8 to SMW 2.4.
$tableName = 'smw_fpt_' . md5( $propertyKey );
Starting with SMW 2.5 the table name is no longer the complete md5 hash instead
substr( base_convert( md5( $tableName ), 16, 32 ), 0, 12 ) is used to get a shorter ID.1