1. A computer system comprising the following: one or more processors; one or more computer-readable storage media having stored thereon computer-executable instructions that, when executed by the one or more processors, cause the computing system to execute a method for processing a query using schema graph traversal, the method comprising the following: an act of receiving a query at the computer system from a query sender, the query specifying one or more relational tables and their relationships that are to be retrieved from a relational database; an act of accessing a schema graph comprising one or more graph nodes representing relational tables and one or more edges that identify relationships between the relational tables, the graph nodes including relational data that was loaded from a first storage area, the schema graph itself being stored in a second storage area; an act of traversing the schema graph, beginning at a set of graph nodes and continuing along the edges to one or more other graph nodes until the query has been satisfied; and an act of reporting the results of the graph traversal.