In a database, cardinality refers to:

In a database, cardinality refers to:

• Which command gets executed first
• How many columns a table contains
• How many rows a table contains
• How many unique values are in a column of a table 

 

 

EXPLANATION

In databases, cardinality refers to the how many unique data values each column contains. High cardinality columns contain unique data values. Low cardinality columns contain few unique values.

SOURCE

http://www.sqlservercentral.com/blogs/matthew-mcgiffen-dba/2017/06/20/statistics-and-cardinality-estimation/