Conceptual modeling

Re: Informal references to entity types

Ken Evans — Thu, 11 Oct 2012 07:40:07 GMT

Clifford,
I don't have a problem with connotations in natural English language.
It seems to me that connotations are essential to ordinary day-to-day communication.

However, when it comes to a universe of discourse that is contained within a fact based model, then you either find a way to assert connotations as fact instances or you don't.

As soon as you include a connotation in a fact based model then the "connotation" becomes just like any other asserted fact - a proposition that is asserted to be true.

Clifford Heath:
It's the fact that English doesn't have different kinds of expressions for these kinds or references that bothers me

Well, there are lots of things about natural English that are bothersome but as soon as you start asserting a set of facts about anything (natural English included) then you are out of the realm of natural English and into the realm of sets of formal propositions - aka the universe of discourse.

Re: Informal references to entity types

Clifford Heath — Thu, 11 Oct 2012 06:22:51 GMT

Point taken Ken - really both kinds of references to a Location are formal though - it's just that one invokes many more connotations (the extended attributes around a Location as Entity Type) and one only invokes the existence of a place having that name. It's the fact that English doesn't have different kinds of expressions for these kinds or references that bothers me, so there is limited capability to naturally verbalise the different kinds of place reference.

Re: Informal references to entity types

Ken Evans — Thu, 11 Oct 2012 06:06:55 GMT

Clifford,
It seems to me that the "problem" that you perceive is caused by the way you are using language.
Specifically, I think that you are mixing formal language with informal language and expecting to make some kind of sense. Can't be done!

According to semiotic principles, words are just symbols that do not have any intrinsic meaning.
When we assert a fact, we are asserting a true proposition.

Thus, the fact type "Person has Nickname", serves as a container for the facts (fact instances) that you want to assert.
e.g. "Mary has nickname Spinner" and "Joe has nickname SQL-Guru"

If you don't want to assert a fact, then you don't assert it and it is not in the universe of discourse.

Any attempt to characterise a fact as either formal or informal is doomed to failure because in the universe of discourse that is a fact based model, all facts are "formal".
You either assert a fact or you don't.

Re: Informal references to entity types

Clifford Heath — Thu, 11 Oct 2012 06:04:36 GMT

Andy Carver:
but maybe those are not what's bothering you...?

The readings and verbalisations come out ok, except that in a whole-model verbalisation I have "location" as predicate text and "Location" as an object type name. I also have the text "Location is called Location Name" or "Location has Location Name" occurring both with and without the initial capital letter. It's this duplication I find disturbing. A capital letter should not make such a big difference when determining how to correctly read a verbalisation. Also recall that I use such verbalisations also as input, so I expect people to be able to write them without the increased chance of error that this duplication entails.

Re: Informal references to entity types

Andy Carver — Thu, 11 Oct 2012 05:24:18 GMT

You are correct, it took place at a location, not at a name. But I'm not clear on why, or in what respect, you find it awkward to have the fact type "Event took place at location called Location Name"

For myself, I would probably call it "Event took place at location that has Location Name". I think all the fact- and constraint-verbalizations etc. would come out OK with that predicate reading... but maybe those are not what's bothering you...?

Re: Informal references to entity types

Clifford Heath — Wed, 10 Oct 2012 10:36:39 GMT

Well, supposing Location is identified by LocationID where each has a Name and other attributes, but we don't want to use a location, just the name. So you get a reading like "Event took place at Location Name". It took place at a Location, not at a Name... but we don't want to use the full location, so you have to say "Event took place at location called Location Name". Neither option is much chop. Similarly for other cases like the Person/nickname examples.

Re: Informal references to entity types

Andy Carver — Wed, 10 Oct 2012 09:29:51 GMT

I just do the value-type approach. Why are you suggesting the fact type readings would necessarily be awkward?

Informal references to entity types

Clifford Heath — Wed, 10 Oct 2012 06:15:03 GMT

I often encounter the situation where I have an Entity Type, say Person or Staff Member, which has a lot of associated details of which many are mandatory, but I also need to record references to individuals that are more informal, such as using their nickname. The Payroll department might need all the info, but if all I want to do is to make a record of who made a certain phone call (to jog the memory for another employee) etc, I often don't want a formal reference. Or in another example, an insurance company requires many facts about a person who is applying for insurance, but has many fewer facts about a witness to an accident, or the name of a third-party - even though a Person is the common supertype here.

In these informal situations, I don't want to record the ID of a person in my Party table (because that implies a lot of knowledge about them), I just want to record their name with no enforcement. The name however is a value type, so fact type readings which use just the name are awkward ("Reference Check Phone Call was made by employee called Name"). If I do it using a supertype of the full Person ET which allows the limited and/or informal identification, the identification pattern must also apply in the case of the subtype.

Basically I feel that all the correct models are a bit awkward. How do you model this kind of situation?