Data Quality Rules: Relational Integrity Constraints
Of all revolutions in information technology, the introduction of relational data models arguably had the greatest impact. These models gave database designers a recipe for the systematic and efficient organization of data.
Now, some 30+ years since their introduction, relational databases are the cornerstone of the information universe.
Relational data models offer a comprehensive notion of the data structure. In doing so, they also place many constraints on the data. We refer to the data quality rules that are derived from the analysis of relational data models as relational integrity constraints. They are relatively easy to identify and implement, which makes a relational data model a starting point in any data quality assessment project. These rules include Identity, Reference, Cardinality, and Inheritance constraints. We discuss each of these rule types below.