what’s a database?
what does a database do?
- stores large volumes of data
- allows rapid access for many different kinds of query
databases includes mechanisms for handling
- secondary storage management: indexing and storage of data that doesn’t fit in memory
- persistence: data shouldn’t go away!
- concurrency control: many users at once
- distribution: users at different sites
- data protection: making sure updates are consistent
- recovery: when system fails, eg
the difference between DB systems and file systems
- programmer doesn’t have to worry about how data is laid out on disk (sometimes called the ‘data independence principle’)