to model various situations and events.
I have read Hugh Darwen's Intro to Relational D'base Theory and Chris Date's magnum opus 'Intro to D'Base Systems',
and am full of admiration for the principled development of D.
But I am still having problems getting my syntax accepted by Rel whenever I stray off into trying more complex queries and operations. The above books are systematic but have not systematically developed my competence in the language of D
I've read the grammars and tried to apply them but somehow, what I really need is a set of incrementally more complex examples where actual commands are displayed.
Is there a source that covers actual commands of increasing length and complexity?