Datalog
https://en.wikipedia.org/wiki/Datalog
Datalog is a declarative logic programming language that syntactically is a subset of
Prolog
.
http://www.learndatalogtoday.org/
Datalog is a declarative database query language with roots in logic programming. Datalog has similar expressive power as SQL.
https://learn-datalog-today-ja.herokuapp.com/