Some db drivers (derby,hsqldb) do not support size ascriptions for certain db types but they nevertheless give them in the jdbc meta data. So basically we need to somehow create a list and exclude the size for those, because otherwise we'll generate invalid DDL. What makes me slightly uncomfortable is, that currently a Slick meta model that contains a size for an INTEGER field is only valid for some backends. So basically you have to make the case distinction when creating the meta model and if that is done in all places where you create a model that's kinda nasty. Not sure what to do about this.