code for given algorithm

Hello,

everyone can any one help me with this coding of this algorithm .

i have tried many different ways to code but unable to find best solution.

1) read from table ZPAT the fields PID and FID where username=sy-user

2)check, if there is a row in ZCORE with PID and FID

3)if yes

               read BID FROM ZCORE where PID and FID

               check, i highest Dnr in ZNEW where PIDand FID is the same value as BID in ZCORE

               if no, in ZCORE set :

                       e_ch='n'  and  call screen 100

               if yes, call screen 100

4) if no

  add new row to ZCORE set:

   a_ch='n'

  e_ch='o'

  BID= highest_BID

(highest_BID is highest value of Dnr from ZNEW  where PID and FID)

call screen 100

information about tables:

ZNEW:

-Dnr (integer)

-PID (integer)

-FID (integer)

=>Comment: There are lines with the same PID and FID, Dnr is a number from 1 to n.

                         at every combination of PID and FID, Dnr is only  once there

Example:

PID          FID           Dnr

4                1               1

4                1               2

4               1                3

4               3                1

ZCORE:

-PID

-FID

-BID

-a_ch (char)

-e_ch (char)

=>Comment: There Every line with  PID and FID has a different value of BID

ZPAT:

-PID

-FID

-username(char)

=>Comment: every username is only once in the table with exactly  one  PID and one FID