What Is a Physical Data Model?
A physical data model introduces the database-specific context missing in conceptual and logical data models. It represents the tables, columns, data types, views, constraints, indices and procedures within the database and/or the information communicated during computer processes.
Physical data models should be built in relation to a specific database management system (DBMS) as well as the specific requirements of the processes that operate based on the data. This often requires denormalization of logical design constructs to maintain referential integrity.
An example of the contextual considerations at the physical data modeling stage is the nature of the data that can/will be processed and the rules regarding how such processes can be executed.
Another key consideration is ensuring the modeled column types are supported in the DBMS, and the naming conventions for entities and columns are observed, preventing problematic semantic overlaps.
The consideration of technological context means physical data models reflect the needs of the technological environment as is, or as intended.