The ORM Foundation

 what i dont understand is the fact that you can say that A exists (and create an existential fact), or you can define the property existence (or inexistence), then go on and say that A has the property existence (creating an elementary fact). isnt it the same content declared in two different ways - once as an existential fact and once ...

i'll appreciate your help also in figuring this sentance out (still from Terry's paper): If a fact type is elementary all its functional dependencies (FDs) are implied by uniqueness constraints. specifically, what are:elementary facts (and what other types of facts exist?)functional dependenciesand may i suggest that an ORM glossary/wiki ...

 Well I’m back…I’m still fumbling with them uniqueness constraints. I think my misunderstanding evolves from confusing the uniqueness idea with what might be termed “identifier”. You see till now we used to denote an identifier value (usually an EmpID for employees or ModuleID for modules, etc.) which we called unique as it is unique in the ...

Dear Terry, I'm afraid I've got another one. kindly inform me when I'm becomming an annoyance....   well on the same article, I examined the ternary mentioned in my post above. i tried to insert it into the NORMA, please see below the results. I know i've got something wrong, but i can't say what it is. here's the ...

[quote user="Terry Halpin"] Dear Rolemo There is more than one correct way to model information. If you want to model the fact f9 the way it was verbalized then the predicate reading should have been "has professors in" and the righthand object type would be Quantity, not PrfQuantity. Notice fact s f14 and f16 are ...

 thanks

 and another one if i may, this time about the difference between values and entities. why can Rank be a valu refering to the entity Academic?  thanks 

here is the facts set:f9 Dept ‘Computer Science' has professors in Quantity 5. f10 Professor ‘Codd EF' holds Chair ‘Databases'.f11 Professor ‘Codd EF' obtained Degree ‘BSc' from University ‘UQ'. f12 Professor ‘Codd EF' heads Dept ‘Computer Science'.f13 Professor ‘Codd EF' has HomePhone ‘965432'. f14 ...

  Hi, I'm working my way through this piece (its in the library), and i'v got a question regarding one of the examples. On page 6 there's a facts set which I'm trying to module, just for practice. I'm not sure how the first fact, f9, should be modeled. Here's my suggestion, I'll appreciate your remarks: it ...

cheers Ken! i believe I got now. I guess i'll still need to snuff arownd a little before i totaly abandon them crows feets, but ORM's case seems quite convincing at this point. and thanks to Terry's NORMA labs i'm getting fong of NORMA as well...what can I say, ORM scratches me right where i itch :-)  thanks a lot!