Re: [elephant-devel] a job for the query system?

OK, in response to your message: I certainly must abandon some
assumptions about OIDs! I do need persistent unique handles for
Things so I can consistently refer to them in my Triples and Theories.

Keeping things unique by the data itself is an interesting
minimalistic proposal... apparently even if OIDs are changing,
compound objects like Triples are stored will still be stored
"safely"? E.g. if I store the triple

[ThingA, ThingB, ThingC]

this will always be (de)serialized so that it points at the right
Things (even if the OID of ThingC, say, happens to change)?

If this works, that would be neat. (If not, I could easily enough
maintain some persistent index and use it to create handles for
Things.)

Your statement of what I hope to accomplish in filtering-by-theory is
correct. Having Theories just be subsets of Things would be fine for
a prototype. Eventually it could be nice to be able to label the
elements of a subset and store such labelings; Pseudo-SQL-wise,
presumably all that amounts to is another column that is ignored
before the "member" function is applied a la your example.