cardinality

Implementers (archive)
1

I had one more question, I said this morning:

What is the use of the numerical part of the Cardinality object, I wonder?

It can be calculated from the number and occurences of the items. Or do
I misunderstand?

For example

events cardinality matches {*;ordered} matches {
    EVENT[at001] occurences matches {0..1} matches {*}
    EVENT[at002] occurences matches {0..1} matches {*}
    EVENT[at003] occurences matches {0..1} matches {*}
}

Because the attribute "events" can have 0 to 3 elements (the occurences
property tells me), the cardinality is {0..3;ordered}
It cannot be something else.

Or do I misunderstand?

Thanks in advance for an answer

regards,
Bert

2

The use for the numerical part of Cardniality, I can think of, is

events cardinality matches {0..2;ordered} matches {
    EVENT[at001] occurences matches {0..1} matches {*}
    EVENT[at002] occurences matches {0..1} matches {*}
    EVENT[at003] occurences matches {0..1} matches {*}
}

In this way teling that only 2 ELEMENT total may be in this list of events

Is that right

Bert

3

Bert
That is right - it is the way of limiting the number of choices as you have said…Sam

Bert Verhees wrote:

4

Sam Heard schreef:

Bert
That is right - it is the way of limiting the number of choices as you
have said...Sam

Thanks, Sam, for the confirmation.

5

Bert Verhees wrote:

I had one more question, I said this morning:

What is the use of the numerical part of the Cardinality object, I wonder?
  

'cardinality' (in ADL) says how big the container can be - imagine it is
like a box containing LEGO pieces. 'occurrences' says how many of a
particular kind of object - e.g. 8x2 LEGO bricks - can be in the
container. 'Existence' says if there is a container or not. For
non-container attributes, 'occurrences' always matches 'existence'.

- thomas