The database is spread across the .dat files of the individual quickstarts. It's not in a format that can be read or edited directly.
The Hockey Databank Project is at
https://github.com/rippinrobr/hockey-databank now, we need to update that link. That was the original basis for the first biographical and stats data in the historical database, but the records have been heavily modified beyond that to include ratings and other data the game needs.