This sample db demonstrates execution of following types of tasks while 
simultaneously displaying the code involved:

 -Referring to controls of one group of nested subforms from another group of 
  nested subforms:
        (a) There are two adjacent sets of nested subforms, each three levels deep.
        (b) Dbl clicking any text box identifies it as Target Control. Thereafter, Dbl 
             clicking any other text box identifies it as Base Control.
        (c) Code in the subform containing Base Control, acts upon Target control and 
             also sets focus on to it. Simultaneously, this code gets displayed at bottom 
             of main parent form.
        (d) For each situation, two alternative styles of VBA code are shown (with and 
             without use of bang (!) operator).
        (e) Extreme case involves Base Control in innermost nested subform at left, 
             acting upon Target Control in innermost nested subform at right (i.e. going 
             up-hill across three levels of parent forms and then down-hill across three 
             levels of subforms).
     4.3 - (i) Query using values represented by controls on forms / nested subforms, 
             (ii) Referring to subroutines (contained in form's modules)  across various 
                  levels of nested subforms:
                 (a) Here too, two adjacent sets of nested subforms, each three levels 
                      deep are used.
                 (b) Dbl clicking any text box on main parent form or various nested 
                      subforms at left, causes its value to be picked up by the query, results 
                      of which, are displayed in the innermost nested subform at right.
                 (c) Simultaneously, the SQL used in source query, gets displayed at 
                      bottom of parent form.
                 (d) VBA code used for calling a subroutine contained in the module of
                      innermost nested subform at right, from various levels of nested 
                      subforms at left, is also displayed.
 
    Note - 
        (a) In a query, reference to form controls is feasible only by using bang (!) 
             operator. 
        (b) In VBA code, parenthesis can be used in lieu of bang (!) operator and are 
             preferred. 
        (c) Thumb rule: Use Dot for one to many situation. Use bang (!) or parenthesis
              for many to one situation e.g member of a collection.

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