1. A method of managing relationships between program code files in an integrated development environment executed on a computer, comprising: detecting a change in one of the program code files as being one of “add”, “remove” and “update”; removing symbols in the changed program code file from a relational schema if the change is one of “remove” and “update”, the relational schema comprising at least two related tables with symbols from the program code files based on a framework for models in the integrated development environment, wherein the at least two related tables comprise a public symbols table and a referenced symbols table; incorporating symbols from the changed program code file in the relational schema if the change is one of “add” and “update”; validating a relationship between the at least two related tables in the relational schema; removing definitions from a definition set for symbols from the changed program code file that were previously removed from the relational schema, the definition set retaining symbol definitions for the program code files; adding definitions to the definition set from the changed program code file for symbols previously incorporated into the relational schema; and producing proxy definitions for use with the definition set for each symbol in the changed program code file previously incorporated into the relational schema without a definition in the definition set.