5 ms·

RDF comes with this whole set of W3C standards, and standardization seems to be a big point in favor if you need to care about interoperability. In terms of da

RDF comes with this whole set of W3C standards, and standardization seems to be a big point in favor if you need to care about interoperability. In terms of data model, RDF may be a bit too web centric to be approachable. Linked Data does not seem much better. This may not be a fully informed view, but so far I think: While the whole area of (broadly) logic-based representations (including datalog, eg. Souffle, datomic, ...) seems to have a bit of a renaissance, all the semantic web stuff seems a bit more like baggage. In other words: if I wanted to build a private knowledge base, I don't want to pick or publish URIs and the fact that all the documentation pushes me towards open/sharing is just getting in the way. In contrast to that, relational databases tech has affected programming languages and frameworks over the decades and goes way beyond triple/quads (e.g. LINQ, or relational mappings). This seems to be a big missed change in a way since, some of the "typing" would in principle be a lot closer to class-based OOP then all the relational stuff.

zozbot234 4y ago
> In other words: if I wanted to build a private knowledge base, I don't want to pick or publish URIs and the fact that all the documentation pushes me towards open/sharing is just getting in the way. RDF supports "blank nodes" for this use case. These are URI-less nodes that can only be referenced within the graph where they're defined. You'd use URI for reference to outside entities, which can be very relevant even in a private knowledge store.
- j-pb 4y ago
  Blank nodes are one of the contested flame warzones of RDF. The fact that they don't have a reified instance means that they are open to collapse with other blank nodes in certain inference scenarios and makes a lot of problems as hard as graph isomorphism. Much better to go with plain old UUIDs instead.
  - zozbot234 4y ago
    RDF uses an open world assumption so "collapse" is always a possibility. That's why there are features like owl:DifferentFrom and related properties.
    - j-pb 4y ago
      What you mean is the unique name assumption, which is distinct from the OWA, and may be viewed orthogonally and applied or not applied in different RDF contexts. The problem with blank nodes is that they circumvent the UNA in every scenario, and you need something like "reified blank nodes" to resolve this, a.k.a. by using UUIDs treated as blank nodes. See the following paper for a more in-depth discussion on the topic https://aidanhogan.com/docs/blank_nodes_jws.pdf https://aidanhogan.com/docs/blank_nodes_jws.pdf
- meh2frdf 4y ago
  URIs a mostly namespaces, it has no bearing on being private data. If you know what your doing you’ll be using ontologies made by others, and like having a namespace for a library you’ll want the same for the terms/classes you use from them.
SemanticStrengh 4y ago
Any opinion on SHACL?
- burakemir 4y ago
  I heard SHACL helps with specifying structure (shape), and more so than OWL which is more about meaning (and where it may be acceptable to have an incomplete but "open" specification). Programming with these structures (triple/quad with shape constraints) would be interesting, general-purpose programs could not easily take advantage in the form of static type-checking. This is roughly the same type of problem as the "object-relational impedance mismatch." I believe some kind of type-checking (shape-checking?) for SPARQL queries might be possible, but don't know if any such thing is implemented.
bawolff 4y ago
>In other words: if I wanted to build a private knowledge base, I don't want to pick or publish URIs and the fact that all the documentation pushes me towards open/sharing is just getting in the way To be fair, i think that is kind of like saying, if i don't care about RDF's primary intended use case, then RDF is a bad choice.
- meh2frdf 4y ago
  I honestly don’t see it matters, it’s a nice option but being open data is totally optional.

zozbot234 4y ago

> In other words: if I wanted to build a private knowledge base, I don't want to pick or publish URIs and the fact that all the documentation pushes me towards open/sharing is just getting in the way. RDF supports "blank nodes" for this use case. These are URI-less nodes that can only be referenced within the graph where they're defined. You'd use URI for reference to outside entities, which can be very relevant even in a private knowledge store.

j-pb 4y ago
Blank nodes are one of the contested flame warzones of RDF. The fact that they don't have a reified instance means that they are open to collapse with other blank nodes in certain inference scenarios and makes a lot of problems as hard as graph isomorphism. Much better to go with plain old UUIDs instead.
- zozbot234 4y ago
  RDF uses an open world assumption so "collapse" is always a possibility. That's why there are features like owl:DifferentFrom and related properties.
  - j-pb 4y ago
    What you mean is the unique name assumption, which is distinct from the OWA, and may be viewed orthogonally and applied or not applied in different RDF contexts. The problem with blank nodes is that they circumvent the UNA in every scenario, and you need something like "reified blank nodes" to resolve this, a.k.a. by using UUIDs treated as blank nodes. See the following paper for a more in-depth discussion on the topic https://aidanhogan.com/docs/blank_nodes_jws.pdf https://aidanhogan.com/docs/blank_nodes_jws.pdf
meh2frdf 4y ago
URIs a mostly namespaces, it has no bearing on being private data. If you know what your doing you’ll be using ontologies made by others, and like having a namespace for a library you’ll want the same for the terms/classes you use from them.

SemanticStrengh 4y ago

Any opinion on SHACL?

burakemir 4y ago
I heard SHACL helps with specifying structure (shape), and more so than OWL which is more about meaning (and where it may be acceptable to have an incomplete but "open" specification). Programming with these structures (triple/quad with shape constraints) would be interesting, general-purpose programs could not easily take advantage in the form of static type-checking. This is roughly the same type of problem as the "object-relational impedance mismatch." I believe some kind of type-checking (shape-checking?) for SPARQL queries might be possible, but don't know if any such thing is implemented.

bawolff 4y ago

>In other words: if I wanted to build a private knowledge base, I don't want to pick or publish URIs and the fact that all the documentation pushes me towards open/sharing is just getting in the way To be fair, i think that is kind of like saying, if i don't care about RDF's primary intended use case, then RDF is a bad choice.

meh2frdf 4y ago
I honestly don’t see it matters, it’s a nice option but being open data is totally optional.