Also note .... Logical DM is database independent, hence can be learned irrespective of which database is present underlying.
For Physical DM, yes you need to have a good understanding of underlying RDBMS [data-types, constraints, etc.]
Please can anyone share more light on CLDM. I know that it has subject area, facets and entities but wanted to know more in depth on it.
You can check the details at following link:
And you can surely use the 'Contact Us' feature. Am not very sure if in-depth knowledge will be available publically as you need to buy cLDM to be able to use it.