- From: Thomas B. Passin <tpassin@home.com>
- Date: Sat, 18 Aug 2001 02:04:43 -0400
- To: <www-rdf-logic@w3.org>
I included a table in my last post, but it seems to have gotten wordwrapped, so I will repeat it with shorter generated ids. > > Now if John did indeed have two fathers after all, the situation would be > more complex, because on merging the two data sources, our processor would > have to convert the hasFather statements into some kind of a container, > which itself would apparently be an anonymous node. It would be something > like this (with apologies for the undefined terms): > subject property object John hasFathers [] [] typeOf container [] RDF_1 randomgenid0 randomgenid0 typeOf malePerson [] RDF_2 randomgenid1 randomgenid1 typeOf malePerson randomgenid0 age 84 randomgenid1 age 86 Without the labels randomgenid0, randomgenid1 it would be much harder to make this set of assertions, if it were possible at all. Certainly we couldn't enter this data into a relational database, or write it down on paper in a table like this, since we would have to use three different "[]" symbols that looked the same but refered to three different resources. To be consistent, of course, I should have used a generated id instead of [] for the container as well. > Indeed, if you think of a set of triples as being rows in a relational > database table, then ask what would be the primary key of that table? The > only sensible answer is that the primary key must be the combination of the > subject and predicate. The "semantics" could also be considered to be a > kind of "business rule", to use an expression from a different domain. > Taking this relational database viewpoint, each node must necessarily have a > value (or label), but it may be that a particular implementation could hide > the label, or exclude it from serialization. Cheers, Tom P
Received on Saturday, 18 August 2001 02:01:46 UTC