A block explorer will use a database to keep track of transactions and will update it as new blocks come in. It will probably not use RPC commands as it receives requests from its users.
This seems a great idea. Why haven't I thought it before... Once a new block is mined, the database will insert a new row of information. Still, though, I don't get how I'll convert the blk.dat files to csv. (So I can import it to a database)