During development of a pipelinetask it may happen that the developer will erroneously define an incorrect datasetType (with incorrect dimensions, or storageClass, etc.). At this point it is impossible to recover without blowing away the registry or sqlite hacking because any fix to the entry will raise a ValueError: Supplied dataset type inconsistent with registry definition error.
We should not allow the ability to delete datasets if a dataset type is associated with them that is being deleted. This would imply that the dataset type has been used. Instead a user should first delete the relevant collection/dataset before deleting the dataset type.