On 8/30/06, GinTon <[EMAIL PROTECTED]> wrote: > > I have seen that for web applications is best far using a ODBMS: > > 1- Objects in an OODBMS can store an arbitrary number of atomic types > as well as other objects. The fact that an OODBMS is better suited to > handling complex,interrelated data than an RDBMS means that an OODBMS > can outperform an RDBMS by ten to a thousand times depending on the > complexity of the data being handled.
Yes, but it depends both on the complexity of the relationships, the complexity of the working set of relationships for a given query, and the amount of data being processed. _If_ your query generates smaller result sets, _and_ the query itself uses a large number of complex relationships, _then_ an OODBMS can outperform an RDBMS. In my experience, if either of these are not true, an RDBMS will generally outperform an OODBMS. > 2- Data in the real world is usually has hierarchical characteristics. > The ever popular Employee example used in most RDBMS texts is easier to > describe in an OODBMS than in an RDBMS. Easier to describe, yes. Easier to index and improve performance when the number of entities gets large, I don't think so. > 4- In a typical application that uses an object oriented programming > language and an RDBMS, a signifcant amount of time is usually spent > mapping tables to objects and back. This "impedance mismatch" is > completely avoided when using an OODBMS. Granted. > 5- The user of an RDBMS has to worry about uniquely identifying tuples > by their values and making sure that no two tuples have the same > primary key values to avoid error conditions. Object-oriented systems have the same equivalence and identity issues. > 6- With an RDBMS it is not possible to model the dynamic operations or > rules that change the state of the data in the system because this is > beyond the scope of the database. With an OODBMS there is no disconnect > between the database model and the application model because the > entities are just other objects in the system. There are two issues here: 1. The majority of data in pre-existing databases lives in RDBMSs. A web framework ignores these at its own peril. 2. As far as I can see, OODBMSs still suffer from the drawbacks of navigational databases with regard to ensuring constraints and asymptotic performance. I'd love to be proven wrong on this count. -- Tim Lesher <[EMAIL PROTECTED]> --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "TurboGears" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/turbogears -~----------~----~----~----~------~----~------~--~---
