Too bad it's called SQL Services.
If it's not a SQL Server (which is presumably a good thing), it would make sense to drop the SQL moniker all together and name it something like Cloud Database Services. If it does offer a SQL query interface, that's fine, but it doesn't mean that SQL should
be part of the name.
If it offered a solid relational calculus DSL and no SQL support, no one would complain.
As soon as you guys are building a new database service, why don't you take it a bit further and allow defining entities and relations between them as predicates in a semi-natural language? Relvars are predicates, according to the relational database theory.
Why not to preserve the relvar's original meaning in the database metadata? That would be a competitive advantage.
PS: What's that S-LINK thing, anyways? Is it a subset of LINK or a superset of thereof?