@Colin, Exactly, 1-1 relationships are a way of optionally extending the current table without having to create a pile of mostly unused fields. An option I want to explore is allowing the user to choose between one of several primary record types. Imagine a table of network devices: a Server, a Network Printer, a Workstation, etc... With each device type needing a different set of additional fields represented by a different 1-1 relationship or a combination of different 1-1 relationships.