A conceptual data model (CDM) helps you analyze the conceptual structure of an information system, to identify the principal entities to be represented, their attributes, and the relationships between them. A CDM is more abstract than a logical (LDM) or physical (PDM) data model.
A logical data model (LDM) helps you analyze the structure of an information system, independent of any specific physical database implementation. An LDM has migrated entity identifiers and is less abstract than a conceptual data model (CDM), but does not allow you to model views, indexes and other elements that are available in the more concrete physical data model (PDM).
Creating a CDM or LDM
- To create a new CDM, select , and choose Conceptual Data Model.
- To create a new LDM, select , and choose Logical Data Model.
- To create a new CDM or LDM by importing one or more ERwin files, select or .
Specifying a Modeling Notation and Other Options
- To specify a modeling notation and set other model options, select .
Generating Other Models
You can generate other PowerDesigner models from a CDM or LDM by selecting Tools >:
- Generate Conceptual Data Model (or press Ctrl+Shift+C)
- Generate Logical Data Model (or press Ctrl+Shift+L)
- Generate Physical Data Model (or press Ctrl+Shift+P)
- [CDM only] Generate Object-Oriented Model (or press Ctrl+Shift+O)
Documentation
For detailed documentation, see Data Modeling.