Item_code      item_name    price      qty 
0001           laptop       260 Rial    1
0006           mobile       150 Rial    1
0008           led          60  Rial    1

Declare
   A number (1 )
   F_name varchar2 (35)
Begin
F_name:=:zz

First_record
While :zz is not null loop

If f_name=:zz then
   :b:=:b+1
A:=A+1
Select icode,inane......
   End if
Next_record
   End loop
Previous_record
End;

F_name:=barcode

:qty:=:qty + 1

DECLARE

  l_match BOOLEAN := FALSE;

BEGIN

first_record;

WHILE :system.last_record != 'TRUE' AND NOT l_match LOOP

  IF :detail_block.item_code = :control_block.barcode THEN
  
    :detail_block.qty := :detail_block.qty + 1;
    l_match := TRUE;
    
  ELSE
  
    next_record;
    
  END IF;
  
END LOOP;

IF NOT l_match THEN

  --Need to add new record at end
  next_record;
  :detail_block.item_code := :control_block.barcode;
  <whatever else you need to set>
  
END IF;

END;
  

DECLARE 
l_match boolean:=false;
BEGIN 
	
			
	FIRST_rECORD;
	WHILE :system.last_record != 'TRUE' AND NOT L_MATCH LOOP

		IF :EMP.item_code=:CONTROL.barcode THEN 
		   :EMP.qty:=:EMP.qty+1;
		L_MATCH:=TRUE;
		ELSE
	   NEXT_RECORD;
		
			
	END IF;

		
	END LOOP;
	IF NOT L_MATCH THEN
	
	select empno,ename into :emp.item_code,:emp.ename from emp where empno=:control.barcode;
		NEXT_RECORD;
		:EMP.item_code:=:CONTROL.barcode;
		
			END IF;
		
		END;

DECLARE 

  l_match boolean:=false;
  l_continue boolean := true;
  
BEGIN 
	
	go_block('emp');	
	FIRST_rECORD;
	WHILE l_continue AND NOT L_MATCH LOOP

    IF :EMP.item_code = :CONTROL.barcode THEN 
      :EMP.qty := :EMP.qty+1;
      L_MATCH := TRUE;
    ELSE
      IF :system.last_record != 'TRUE' THEN
        NEXT_RECORD;
      ELSE
        --checked last record, time to stop
        l_continue := FALSE;
      END IF;
    
      
    END IF;

  END LOOP;
  
  IF NOT L_MATCH THEN
  
    ..........
    
  END IF;
    
END;