Posted by sqlservernewbie on 04/12/07 15:19

Hi Everyone,


Here is a theoretical, and definition question for you.


In databases, we have:

Relation
a table with columns and rows

Attribute
a named column/field of a relation

Domain
a set of allowable values for one or more attributes

Tuple
a row of a relation

Degree
the number of attributes a relation contains
Number of fields in a table

Cardinality
the number of tuples/rows a relation contains



But!

What is the definition for the number of unique values in a field?

So, if you have 100 rows in a table, and the field is
the gender field, with only values of: Y, N.
You have 2 unique values.


What do we call this concept?
"the number of unique values in a column?"

Is there one?


Thanks a lot!

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