UniqueValueRatio
Checks the unique value ratio of a column against a given expression. A unique value ratio is the fraction of unique values divided by the number of all distinct values in a column. Unique values occur exactly one time, while distinct values occur at least once.
For example, the set [a, a, b] contains one unique value (b)
and two distinct values (a and b). So the unique value ratio of the
set is ½ = 0.5.
Syntax
UniqueValueRatio<COL_NAME><EXPRESSION>
COL_NAME – The name of the column that you want to evaluate the data quality rule against.
Supported column types: Any column type
EXPRESSION – An expression to run against the rule type response in order to produce a Boolean value. For more information, see Expressions.
Example: Unique value ratio
This example checks the unique value ratio of a column against a range of values.
UniqueValueRatio "test_score" between 0 and 0.5 UniqueValueRatio "Customer_ID" between 0 and 0.9 where "Customer_ID < 10"
Sample dynamic rules
UniqueValueRatio "colA" > avg(last(10))UniqueValueRatio "colA" <= index(last(10),2) + std(last(5))
