Please suggest a data entry tool (if one exists) for a single large sparse table.
row x, checkbox list of 300 columns, check 5 that pertain, enter data for those 5.
row x+1, same checkbox, check different 14 that pertain, enter data for those 14.
row x+2, checkbox does not contain column, add column title and data type, check new column created and 33 others that pertain, enter data for those 34.
Although possible, it's inconvenient to do in a worksheet - too much tabbing/arrowing around.