Powerdesigner defines cdm, ldm, and pdm
Conceptual Data Model
The conceptual data model (CDM) helps you analyze the conceptual structure of the information system, and then identify the main entities to be described, the attributes in these entities and the relationships between these entities. The conceptual data model is more abstract than the logical or physical data model.
Logical Data Model
The Logical Data Model (LDM) helps you analyze the structure of the information system, which is independent of any specific physical database implementation. Ldm already involves entity identifiers. It is not as abstract as cdm, but does not allow you to design views, indexes, and other more specific physical data model elements.
Physical Data Model
The physical data model (PDM) helps you analyze tables, views, and other database objects, including the multidimensional objects required by the data warehouse. Pdm is more specific than cdm and ldm. You can perform modeling, reverse engineering, and generate all the most popular databases.