A logical data model is a detailed representation of data requirements, usually in support of a specific usage context, such as application requirements. Logical data models are still independent of any technology or specific implementation constraints. A logical data model often begins as an extension of a conceptual data model.

In a relational logical data model, the conceptual data model is extended by adding attributes. Attributes are assigned to entities by applying the technique of normalization, as shown in this figure. There is a very strong relationship between each attribute and the primary key of the entity in which it resides. For instance, School Name has a strong relationship to School Code. For example, each value of a School Code brings back at most one value of a School Name.