Many "relational" databases do waste space, but since even M databases can project a SQL view (relation), that argument may not always be accurate. In my opinion it's misleading for folks to claim that VistA is hierarchical and therefore cannot project a relational view.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Kevin Toppenberg Sent: Monday, September 19, 2005 12:37 PM To: hardhats-members@lists.sourceforge.net Subject: [Hardhats-members] Re: Wiki additions: [was: web evaluation tool] So then, is the argument that relational databases store empty space incorrect? Kevin On 9/19/05, Gregory Woodhouse <[EMAIL PROTECTED]> wrote: > This is actually not true. flat tables are the abstraction presented > to the user (or programmer) with relational databases, but the > underlying storage model is, more likely than not, based on B-trees, > just as it is in MUMPS. This can be confusing, because the basic > abstraction presented to the user in MUMPS is multi-branching trees, > but that abstraction is not the same as the underlying storage model. > > === > Gregory Woodhouse > [EMAIL PROTECTED] > > "The most incomprehensible thing about > the world is that it is at all comprehensible." > --Albert Einstein (1879-1955) > > > On Sep 19, 2005, at 11:56 AM, Kevin Toppenberg wrote: > > > 2) What is the fundamental difference between a relational database > > and > > a hierarchical database and how does that effect the end-user? (Should > > we even care? If so why?) > > > > Another difference is the way the data is stored. M data is stored in > > b-trees, as compared to flat tables (I believe). This leads to faster > > data acess, and less CPU power needed. > > > > Also, the database in M is called by some a "sparce array." This > > means that there are no "blank spaces" left for data to be later > > filled into. So with M, if there is no data present, then no space is > > wasted. I find this to lead to many many fields being defined for a > > given file. With a traditional database, having all these fields with > > empty/wasted space, would lead to huge database files. But with M, > > one can can store years of patient information on a relatively small > > disk. > > > > > > ------------------------------------------------------- > SF.Net email is sponsored by: > Tame your development challenges with Apache's Geronimo App Server. > Download > it for free - -and be entered to win a 42" plasma tv or your very own > Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php > _______________________________________________ > Hardhats-members mailing list > Hardhats-members@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/hardhats-members > ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ Hardhats-members mailing list Hardhats-members@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/hardhats-members ------------------------------------------------------- SF.Net email is sponsored by: Tame your development challenges with Apache's Geronimo App Server. Download it for free - -and be entered to win a 42" plasma tv or your very own Sony(tm)PSP. Click here to play: http://sourceforge.net/geronimo.php _______________________________________________ Hardhats-members mailing list Hardhats-members@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/hardhats-members
