The database used by the search forms is the same data that is used to generate the printed SCA Armorial and SCA Ordinary. It is a flat text file roughly 6 megabytes in size. The file format is documented online.
The database is protected by copyright, but that broad blanket permissions have been granted for verbatim redistribution and personal use. See the copyright notice for details.
You should be able to download the database via HTTP from http://sca.uwaterloo.ca:80/OandA/oanda.db (not compressed).