How to access Userdefined MasterData through script

Hi Expert,

My clients requirement is to find and add the approver in Contract Document.

We are having a Userdefined Masterdata which is having 4 columns (Region, Product, Agreement range ($0-100, $101-1000, >$1001)). so the table looks likes

Region   Product    Agreement Value

                             $0-100     $101-1000     >$1001

USA      ALU            A                B                 C

USA      NIK             D                E                 F

UK        ALU            G                H                 I

UK        NIK             J                 K                 L

A,B,C, etc are userid's of approver. We are having 40000 entries in the above Userdefined Masterdata.

Please suggest the convenient way to find exact approver from this table through script also consider the performance of the system.

Appreciate your help.

Regards,

Ravi Gupta