In computing, Cardinality is a word that denotes the uniqueness of data in a column. Columns containing highly unique data—ID numbers, for example, which are unique to each individual— are said to have “high cardinality.” Columns can also be defined as possessing “normal” or “low” data cardinality.
Cardinality in data can also express the relationships that tables have with one another, and are defined in their cardinality as either “many to many,” “one-to-many” or “one-to-one.”
