A computer implemented method of constructing a computer application for automatically implementing a complex comparison programming task provides a compare design wizard to a display of a user's computer. The user interacts with the compare design wizard to specify (a) at least first and second data groups each containing associated data elements, (b) one or more keys from the first data group, and (c) one or more keys from the second data group, the keys comprising data elements that the user desires to be compared by the computer application. The user further interacts with the compare design wizard to specify one or more actions to be taken by the computer application based on data element comparisons to be performed by the computer application of: the keys matching between the first and second data groups; excess data being found in one of the groups; and excess data being found in a different one of the groups.