In the bullion bars database we have the signatures for about 250,000 gold bars and 800,000 silver bars. I'm at the stage now where I need a consistent referencing number — currently the unique identifiers get created fresh each time I import a major set of data, which solves a bunch of other problems but makes it difficult to permanently catalog interesting bars. If you're not into 'Barspotting' please feel free to tune out - this is another of those posts where I'm just talking out loud, trying to solve some boring questions open for discussion.
