Relational Algebra Tutor Chris Roe Visual support for relational algebra queries Relational Algebra queries can be hard to understand in their symbolic form. To understand how an EDDI query such as ?(allfruits * apple) %name, begin, price; works you need to know the meaning of each of the symbols and how that applies to the tables you are working with. This environment provides support for visualising EDDI queries and uses colour coding to show how output tables are created from the source tables of the query. 2003 9 4 ratRoe2003 model PhD tkeden %eden %scout %donald screenshot.jpg README sqleddiWard2003 tool HCI tutorial