Nested relationships

[Jeff_Brown]

Could you represent "babies need calcium because babies build bones".

It is straightforward to represent "babies need calcium" and "babies build bones" as two edges in a graph (where the nodes are "babies", "calcium" and "bones"). But the "because" relationship would then be a relationship between two edges.

Most information -- in particular, most sentences -- consists of nested relationships like these.

[miko]

Hi Jeff, I am not 100% sure what is the question, but in Grakn and Graql relationship are first class citizens (or concepts as we call them) and so are perfectly allowed to play roles in other relationships. In your case, you are absolutely allowed to define a "because" relationship between the "babies need calcium" and "babies build bones". In fact, under the hood, both entities and and relationships are nodes in the graph. That is how we build, for example, n-ary relationships.

In a Grakn graph, the nodes represents the "concepts" of your knowledge domain, including the relationships, while the edges are the meta-relations between those concepts.

[Jeff_Brown]

Wonderful!

Do you have to specify the relationships to be used in advance, or can they evolve? For instance suppose I had a lot of binary "is a" edges, and then I wanted one of them to be in a unary "maybe" relationship. For concreteness, I might want to change "(the platypus) is a (mammal)" to "maybe ((the platypus) is a (mammal))".

Would that change be possible? Would it cause the platypus-mammal relationship to switch from being an edge to being a node? Would it have been a node the whole time?

[filipe]

Hi @Jeff_Brown,

Yes such a change is possible. You can change the ontology and the relationships between concepts. Not everything needs to be set in stone in advance.

Please note though, that changing the ontology (and "isa" edges for example) after data has been loaded can result in longer commit times due to having to revalidate a lot of the data. For example if you suddenly changed from "(the platypus) is a (animal)" to "(the platypus) is a (human)" we need to check if all the relationships your platypuses are in are still valid, because an animal can be in different relationships than a human.

Hope that is the answer you were looking for.

[xMAnton]

Hi @filipe,

from your last answer, I gather that I could start working with a draft ontology, load some initial data, do appropriate queries to validate entities, relations, roles and resources for my needs, then extend the ontology to add more types, relations etc. and load new data, always preserving previous loaded data.

Is it correct?

Antonio

[miko]

Hi Antonio,

That is correct indeed.

Michelangelo