It was E.F.Codd, for one thing, and not Ted. :) But... relational models work very well for *reporting* but not so much for other things. They're kinda slow, for example. Hierarchical and set-related models (document-based, ODBMS, and CODASYL dbs, respectively) are much, much faster for some operations, and slower for others.
Relational models excel in reporting and warehousing. The rest... meh, they're kinda slow on updates and set relationships. We're just so used to the lack of speed that we think it's the norm. However, if you're doing a lot of updates or your set modifications are common, you'll typically find the other models faster, and - depending on your taste - easier. Certainly transaction processing is easier with nonrelational. That's not to say that relational databases are *bad* -- they're just very good at structured data, used for reporting, which is what they were used for most often. Now they're seen as part of the background noise of data storage, so everyone converts their problem into something the relational database can use - as opposed to finding the solution that fits the problem well. We've decided to let our tools dictate our solutions, instead of picking our solutions to fit our problems. On Fri, Mar 26, 2010 at 10:34 AM, Rami Ojares <[email protected]> wrote: > Hi, > > I only now stumbled onto JackRabbit project. > And a basic question about it rose in me spontaneously. > > 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? > > Features mentioned like full text search, versioning, transactions, > observation, and more > can be just as well implemented with the relational model. > > And what does unstructured data mean? > It sounds to me like random noise. > > - rami > -- Joseph B. Ottinger http://enigmastation.com
