Gokul Kamaraj and Liliana Kadar continue a series on operational database tooling in Hadoop:
Referential integrity is supported through the implementation of ‘constraints’ as well as enforcing business rules for attributes in the table.
Constraints are configurable, and you can use it across different tables. Keep in mind that you have to choose a behavior depending on the specific configuration given to that constraint.
This is rather underdeveloped compared to relational database platforms, but it’s still an improvement over the olden days, in which referential integrity was “write code which does that after the fact.”