I feel I must clarify my position on the conceptual equivalence of a node and a field (or a row, or whatever). Please note that I think the node and the xml-database is a better way because it is more flexible with less trouble, but the fact is that we sometimes encode metadata in a field, for example the single text-field "contact" could be encoded as "type;value" like "phone;+46 920 259677" or "email;[EMAIL PROTECTED]", which would then have to be programatically split at those rare times when we need just the one value.
So I still hold that as a user it is possible to view my data in whatever way is more convenient for me. (Perhaps it is even my right?). Also this nice term metadata is in an xml-document just placed in a node like everything else, sometimes in an attribute-node, sometimes in a text-node. There is nothing that forces me to place metadata in an attribute and "real" data in a "real" node, sometimes the mere presence of a node IS my data. > -----Ursprungligt meddelande----- > Från: Kimbro Staken [mailto:[EMAIL PROTECTED] > Skickat: den 25 oktober 2000 17:51 > Till: [EMAIL PROTECTED] > Ämne: Re: First reflections > > > 2) What is the difference between a table in a rdbms and a > node in the = > > xml > > sense (other than that a node is a more general concept)?. > For that = > > matter, > > what is the difference between a row (or even a field in a > row) in a = > > table > > and a node? > > A Node is most closely related to a single field in a > relational table, > however there is a very significant difference in that a node > can have both > metadata (e.g. attributes) as well as child nodes. This is > something that a > field in a relational table can not have. > > > > > What is the difference between a record-set or row-set or > field-set and = > > a > > node-set (again other than that a node-set is more general)? > > The same applies here, it's metadata and hierarchy that are > very different > from the relational model. If you want to store a hierarchy > in a relational > database you have to flatten it and map it to tables, > metadata must also be > mapped. When you retrieve your row set you have to carefully > construct your > query to reconstitute the original hierarchy. In an XML > database this isn't > necessary, retrieving the node set is going to retrieve the > whole hierarchy > under the node as well. > ------------------------------------------------------------------ Post a message: mailto:[EMAIL PROTECTED] Unsubscribe: mailto:[EMAIL PROTECTED] adminstrator: mailto:[EMAIL PROTECTED] Read archived messages: http://archive.xmldb.org/ ------------------------------------------------------------------
