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 algebra, 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?