Datalog is a logical query language that combines principles of logic programming with database theory, focusing on recursive queries. The provided implementation in Clojure supports in-memory relational database formats and allows for the addition and modification of data through functions like add-tuples. Datalog lets you define inference rules to apply to your data, with the ability to create recursive rules for transitive closures. Queries are made to extract information from the rules and database, with the option to parameterize queries using double ‘?’. Work plans can optimize query performance. A detailed example and further information can be found at the provided links.
https://clojure.github.io/clojure-contrib/doc/datalog.html