get registration number

Hi Guyz i want to get registration number and show Registration Number in Report of Customer can you tell me what is the relation between dirpartytable and custtable

this is my code 

DirPartyTable DirPartyTable;
DirPartyLocation DirPartyLocation;
taxRegistration taxRegistration;
CustTable custtable;

select * from DirPartyTable
where DirPartyTable.Name == "Brich company";

select * from DirPartyLocation
where DirPartyLocation.Party == dirPartyTable.RecId;

select registrationNumber
from taxRegistration
where taxRegistration.DirPartyLocation == dirPartyLocation.RecId;

//info(strFmt("reg %1",taxRegistration.RegistrationNumber));
info(strFmt(DirPartyTable.Name,taxRegistration.RegistrationNumber));

now i want to make relation between where DirPartyTable.Name == "Brich company";

i want registration number on behlf of name in my report of another one so can you guide me?