Some companies have data modelers who generate the data definition language (DDL) for the database; some companies have data modelers who ONLY do the logical model, leaving the physical stuff to the database administrator; and then there are some companies where the data modeler works hand-in-hand with the database personnel. Which type is your company?

I am usually happy when a client has ANYBODY who can model and understand the physical database design. It makes my job so much easier. I can talk logical entities, attributes and relationships using super/subtypes, etc. with that person. I can also talk the design and performance of the database design itself. For the data warehouse we always make sure our design is tuned and performs well for loading, as well as querying. The balance can be difficult to achieve. Since the data warehouse is a physical store of data, logical modeling may not be so important to your company. However, when it comes to master data management, the logical model is KING! From the logical model, with all the relationships, we can then create the physical model that balances input and output of data. MDM should include NO history, to keep it fast and lean. The MDM physical design should have a minimal amount of indexes to keep updates from corporate applications fast.

Logical and physical modeling requires skills and a good understanding of what the business is trying to achieve. If you have a modeler that can do both logical and physical model, KEEP THEM HAPPY!