1. A multi-node computer system comprising: a plurality of compute nodes that each comprise a processor and memory connected by a plurality of virtual networks; an access setup mechanism that configures access control data on the compute nodes, wherein the access control data includes a security class assignment table, wherein the access control data further includes a security class for each of a plurality of database objects; and an access control mechanism that controls access to the plurality of database objects over the virtual network by sending a query to a particular security class so the query is only seen by those nodes that are authorized by the particular security class indicated in the access control data.