What about the use case where a user wants to try OGM with an existing model: should he has to replace the generation strategies, if the datastore does not support them, or should OGM use the available strategies to simulate the required behaviour (as best as it is can)?

Davide D'Alto that's the big question and the reason why I mapped to so many things in the first place. But I'm fine with being strict and open it up with some flag if that makes Gunnar happier.

Gunnar Morling if a "table" lookup is inefficient in Neo4J then we have a problem for all entities anyways. I'm not sure your efficiency argument holds. One query per generator seems fine to me anyways.

About GridDialect#nextValue, can't we either split methods or add the necessary parameters?