This can be achieved one way using globals in your summary table and a relationship to your owners table, this will also give you the opportunity to list all the found records in a portal so you can select and view them quickly.
What you need to do first is create two global Date fields in your SUMMARY table, gDateStart and gDateEnd, and you make them globals by clicking on the 'Options...' button after creating them and going to the Storage tab and clicking the box label 'Use global storage'.
Now go to your relationship graph and create a new table occurrence for OWNERS, or use your main OWNERS table, and link it to the SUMMARY table with the following relationships:
gDateStart ≤ DateNextCheck
gDateStart ≥ DateNextCheck
and once that is done create the calculation that will display the number of records in the SUMMARY table. ( Summary_OWNERS is teh name of the TO I have linked to SUMMARY )
CountChecksDue ( Calculated Text )
num = Count ( Summary_OWNERS::DateNextCheck )
; // Start of Calculation
case ( num = 0 ; "no records found" ;
num = 1 ; "There is only 1 record" ;
num > 1 ; "There are " & num & " records'
) // End of Let function
And that should do for defining the fields and relationships
Now you just need to amend the OnLayoutOpen script on your summary layout to set the two global fields to the current date and the current date plus 30
SO it woudl be:
Set Field [ SUMMARY::gStartDate ; Get ( CurrentDate ) ]
Set Field [ SUMMARY::gEndDate ; Get ( CurrentDate ) + 30 ]
I hope this helps and let me know if anything is unclear