A rule is business logic that defines conditions applied to source data when you run a profile. It is a midstream mapplet that you use in a profile. You can validate a mapplet that you want to use as a rule in a profile.
A rule must meet the following requirements:
The rule must contain an Input and Output transformation. You cannot use data sources in a rule.
The rule can contain Expression transformations, Lookup transformations, and passive data quality transformations. The rule cannot contain any other type of transformation. For example, a rule cannot contain a Match transformation, as it is an active transformation.
The rule does not specify cardinality between input groups.
Rule functionality is not limited to profiling. You can add any mapplet that you validate as a rule to a profile in the Analyst tool. For example, you can evaluate postal address data quality by selecting a rule configured to validate postal addresses and adding it to a profile.