Message from discussion
Ternary Relationship cardinality
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From: Jonathan Leffler <jleff...@earthlink.net>
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Subject: Re: Ternary Relationship cardinality
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Date: Tue, 19 Sep 2006 07:10:11 GMT
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mikl...@gmail.com wrote:
> I am working on an assignment which has 2 ternary relationship. I'm
> can't figure out their cardinality.
>
> Maybe I am going through one of those mental blocks...
>
> Can someone give me some cardinality examples for N-ary relationships?
> all the pics i found on google images don't include this..
Cardinality = number of { rows, records, tuples } in a relation.
Count the number of 'rows' in the table - that's the cardinality.
Degree = number of { fields, columns, attributes }.
Ternary relations have degree 3 (or 'are of degree 3').
> My other option is to convert the 3-ary relationship into a weak
> entity.. but I'll definitely loose marks on that
You may also lose marks for misspelling 'lose' (and not using plurals,
and using "I'm can't" for "I can't", etc).
> [...]
--
Jonathan Leffler #include <disclaimer.h>
Email: jleff...@earthlink.net, jleff...@us.ibm.com
Guardian of DBD::Informix v2005.02 -- http://dbi.perl.org/
