1. A computer system including instructions stored on a non-transitory computer-readable storage medium, the computer system comprising: an upgrade portion identifier configured to identify a plurality of databases of an original system for upgrade; a parameter module configured to calculate a plurality of parameter values representing aspects of the plurality of databases; a logic module configured to: for each of the plurality of databases, convert a parameter value into a degree of membership within a set representing the parameter value; and rank each of the plurality of databases based on the degree of membership; and a selection module configured to select at least a portion of the plurality of databases for upgrade during uptime of the original system based on a limitation of an upgrade resource and the ranking of each of the plurality of databases.