A logical data model or LDM is a graphical
representation of some of the business requirements and especially the concepts manipulated by the business member. LDM
is independent of the technology of implementation, and is mostly used as a communication vehicle for the business
analyst and to prepare the implementation of data models.
From the point of view of an object-oriented developer
data modeling is conceptually similar to class modeling. With data modeling you identify entity types whereas with
class modeling you identify classes. Data attributes are assigned to entity type just as you would assign
attributes and operations to classes. Traditional data modeling is different from class modeling because it focuses
solely on data – class models allow you to explore both the behavior and data aspects of your domain, with a data model
you can only explore data issues.
We use UML simple class diagram to represent
a Logical Data Model but by applying Agile's principle of multiple
models, it is possible to use other diagrams.
Logical Data Models are used to explore the domain concepts, and their
relationships, of the problem domain. This could be done for the scope of a single project or for the
entire enterprise. LDMs depict the logical entity types, typically referred to simply as entity types, the data
attributes describing those entities, and the relationships between the entities.
Defining a logical data model prepare for future reuse, and help to build common definition of terms. This is one of
major building block for enterprise data model.