SQl is not relational for all the hype that ORACLE/IBM/Microsoft have put out over the decades.
SQL fails to be relational because it doesn't deal with relations. At its base, it deals with bags of records and not relations of tuples.
Tutorial D is relational but has a lot of warts. D4 was relational but changed to allow access to SQL databases.
If my understanding is correct Rel (by Dave Voorhis) is a Java implemented Relational DBMS (a true RDBMS). There are a variety of projects also are designed to implement a true RDBMS. Another might be Andl (by David Bennett) and there is also SIRA_PRISE (by Erwin Smout). There are more and are documented at www.thethirdmanifesto.com, if you are interested.
SQL fails to be relational because it doesn't deal with relations. At its base, it deals with bags of records and not relations of tuples.
Tutorial D is relational but has a lot of warts. D4 was relational but changed to allow access to SQL databases.
If my understanding is correct Rel (by Dave Voorhis) is a Java implemented Relational DBMS (a true RDBMS). There are a variety of projects also are designed to implement a true RDBMS. Another might be Andl (by David Bennett) and there is also SIRA_PRISE (by Erwin Smout). There are more and are documented at www.thethirdmanifesto.com, if you are interested.
[EDIT - correct spelling erro]