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).
You can use a logical model as an intermediary step in the database design process between the conceptual and physical designs:
Start with a CDM containing entities, attributes, relationships, domains, data items and business rules. If need be, you may develop the CDM in several design steps starting from a high level model to a low level CDM
Generate an LDM. Create indexes and specify FK column names and other common features
Generate one or more PDMs, each targeted to a specific DBMS implementation
This design process allows you to keep everything consistent in a large development effort.
To create an LDM, see Creating a Data Model. For detailed information about logical diagrams, see Logical Diagrams.