Theoretical definition for the number of unique values?

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! Received on Thu Apr 12 2007 - 10:19:36 CDT