No mention of SQL? Relational algebra is a very prominent example of one-way constrain system, if you look at individual nodes in the query execution tree. Also

No mention of SQL? Relational algebra is a very prominent example of one-way constrain system, if you look at individual nodes in the query execution tree. Also, remember to consider index maintenance and materialized/indexed views. I like that article is well-researched with references to various papers, there is definetly some good reading material there.