18. The method according to claim 12 wherein the changed program code file change is one of “add”, “remove” and “update” and wherein the step of modifying the definition set comprises: removing definitions from the definition set for symbols from the changed program code file that were previously removed from the relational schema; and adding definitions to the definition set from the changed program code file for symbols previously incorporated into the relational schema.
19. The method according to claim 18 wherein the changed program code file contains public symbols having a definition in the changed program code file and referenced symbols only being referred to in the changed program code file, and wherein the step of adding definitions comprises: parsing the changed program code file to extract definitions for the public symbols therein; and adding the extracted definitions to the definition set.