dbaccess xyzdb << EOF >> db$abcd.log 2>&1          ------------------- connecting to database
alter table $abcd add ( encrypt char(11) ) ;       ------------------- altering the table to add a new column called encrypt with a datatype char of length 11 
create index idx_neuker on $abcd(insys_serial) ;    ------------------ creating a index named idx_neuker on table on column insys_serial
update statistics high for table $abcd(insys_serial);
create procedure p$abcd() ------- procedure started
returning char(40); 
DEFINE acc_num char(20); ---- defining the different variable with datatypes like char an dinteger with different length as mentioned within ()
DEFINE i integer;
DEFINE sum integer; 
set debug file to 'pev_rech_yyyymmnn.log'; ------ creating the debugg file with a name pev_rech_yyyymmnn.log
trace 'begin update';
let i = 0; ------ initializing the variable to 0
let sum=0;
begin work;  ------ begin here
foreach up_cur with hold for ----- in this loop they are selecting the insys_serial into a variable called acc_num and updating the field encrypt=msisdn
select insys_serial into acc_num from $abcd
update $abcd set encrypt=msisdn where insys_serial=acc_num;
let i=i+1;                   --------------- this is done till it process for 10000 records the commit is done and it will loop back
let sum=sum+1;
if i=10000 then 
trace 'record processed '||sum;
commit work;
let i=0;
begin work;               
end if
end foreach               ------- ending the if and for loop
commit work;
trace 'procedure ok! total processed records are '||sum;
return "procedure complete!";
end procedure;
execute procedure p$abcd();
drop procedure p$abcd ;  -- deleteing the index and procedure here
drop index idx_neuker;
EOF