Relational does not dictate underlying implementation

Post #105,937 by tablizer 6/13/03 2:06:01 AM 6/13/03 2:08:29 AM Reply	Relational does not dictate underlying implementation whether the "guts" use navigational structures or not is immaterial. Everything is 1's and 0's in the end, but we hide that fact most of the time. Navigational structures perhaps are the assembly language or machine language of databases. ________________ oop.ismad.com Edited by tablizer June 13, 2003, 02:08:29 AM EDT Expand All History
Post #106,254 by jb4 6/16/03 4:28:23 PM Reply	Bryce, what ARE you talking about Underlying any relational database is a table structure, with links between key fields in the tables. The ability to "relate" between tables is indeed a navigational structure. It's inherent, you get ift for free, and how it's done doesn't matter, so long as it works. I don't know how you can say that a relational DB doesn't use a navigational structure with a straight face, unless you're trolling (in which case, I wouldn't expect a straight face). jb4 "We continue to live in a world where all our know-how is locked into binary files in an unknown format. If our documents are our corporate memory, Microsoft still has us all condemned to Alzheimer's." Simon Phipps, SUN Microsystems
Post #106,298 by tablizer 6/17/03 2:25:34 AM Reply	You misunderstood me Underlying any relational database is a table structure, with links between key fields in the tables. Not necessarily. They are only links when you want them to be. For example, a join expression can be anything you want it to be: select * from cities1, cities2 where cities1.name like cities2.title \|\| '%' matches similarly-named cities. This is a purely "calculated" join. There is no pre-set links. RDBMS may put commonly used links in some kind of index-like thing to speed them up, but that is an optimization detail that is hidden from the query builder. In relational, you ask WHAT you want, not HOW to get it. (This is in some ways similar to Prolog I hear.) With nav's, you generally have to tell it how to get stuff, which "path" to take. I don't know how you can say that a relational DB doesn't use a navigational structure with a straight face I did NOT say they didn't. My point is that it is an implementation detail that is hidden. Languages like Python or Pascal may use bytecodes or machine code underneath to carry out commands, but the language user does not have to really care. The relationship between relational and nav structures is similar. Navigational is the proverbial bytecode of structure manipulation. ________________ oop.ismad.com
Post #106,300 by CRConrad 6/17/03 3:27:56 AM Reply	And why do you think that happens all the time...? (new thread) Created as new thread #106299 titled [link\|/forums/render/content/show?contentid=106299\|And why do you think that happens all the time...?]

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