Is there any DBMS that does not rely upon SQL?

This topic is somewhat related to this question. There my answer was motivated by the assumption that SQL is necessary to access data in every database I know.

AFAIK, whether you are directly accessing data with some dbms client or you are performing a row-by-row operation (i.e. cursor) with some program (c++, java, cobol, whatever) using some db connector, you need, at some point, to write some SQL to actually read/modify data.

Now I'm asking: is this true in general? Is there any RDBMS that does not rely upon some SQL dialect?

I know that SQL is (not strictly) based relational a开发者_开发问答lgebra, which is the foundation of the relational model by E.F.Codd (1970).

So what I'm asking is also: is there any RDBMS that give a better implementation of the relational model?

The D language (Date and Darwen) was created as a relational language, and one of the first things they rejected was trying to make it match up with SQL.

There are several implementations (Rel, D4, etc) of D, but I'm not sure how tested these are in real, commercial settings.

You could look at the DEE project by Greg Gaughan, and the Alf project by Bernard Lambeau. Not necessarily genuine DBMS's (Alf is just the algebra, and offers no updating facilities).

The TTM website (http://www.thethirdmanifesto.com) lists all the projects that are inspired by it (and of which the authors are aware, of course).

BTW I like that double negation in your question.