BSEG and FAGLFLEXA tables have same records or not

Hi

I am programmer and i am trying to fetch BSEG-SEGMENT data for Customer Open items , but BSEG is a cluster table, so i am trying to get from BSID and FAGLFLEXA table instead of BSEG table,,

here my question is whether all BSID records exist in FAGLFLEXA or not ....

I have cross checked BSID records with FAGLFLEXA table records and its matched........

Please help whether i can use BSID and FAGLFLEXA tables instead of BSEG to fetch SEGMENT field value or is there any other alternative.

Thanks

Sireesha