File Uniqueness? (Score 1)

I don't know much about these new database file system schemas. I was just curious how a file's uniqueness is determined? Since a flat file space means that "foo.txt" can (and will) occur several times in the same physical page, the system obviously can't use a traditional naming schema as the primary key in the database. Perhaps the system uses something like an MD5 checksum to determine uniqueness, and just stores the filename as metadata? If so, it would be cool if the hashing algorithm was standardized, as that would do wonders for P2P file system searching and data mining.