On Fri, Mar 26, 2010 at 15:34, Rami Ojares <[email protected]> wrote: > Early in the seventies Ted Codd published relational model as an improvement > over the hierarchical model that had been used for data storage until then. > > So why do we still need a hierarchical model for data storage?
In addition to what others have said already: a major requirement for going from files to RDBMS in the 70s was the big cost of storage back then. Hence normalization was considered important, and the relational model made the best use of the disk space available. But nowadays this is different, so "denormalization" is ok. It makes reads faster. And it is absolutely needed for large databases that span multiple servers. Regards, Alex -- Alexander Klimetschek [email protected]
