DIFFERENCE BETWEEN CHECK TABLE AND VALUE TABLE

Value Table :
 1. Is to display possible values for a field. When the particular field is placed on any screen when you press       F4 then possible values are displayed from Value table.
 2. Maintain value table at domain level.

Check Table:
  1.check tabke works at table level.
  2.When there is a foreign key ralationship between 2 tables then,
   the first table is called as foreign key table and the table which you have a relationship from this table to the    second table is check table.
   You can enter values in the foreign key table if there exist a record in check table.

DIFFERENCE BETWEEN FUNCTION MODULE AND SUBROUTINE

FUNCTION MODULE	SUBROUTINE
.they can be tested by itself	they cannot .
.they can be remote enabled	they cannot .
they can handle exceptions	Only a few can handle.
.they have to be maintained in  a function group.	It is not necessary
.Can return the value	Can not return the Value
Executable programs	NON Executable programs