Basic Data Modeling Concepts
Conceptual > Logical > Physical
What is an Enterprise Data Model?
An Enterprise Data Model (EDM) is comprised of pictures or diagrams that represent the critical components of your business such as your products, services, consumers and other key players.
Organizations that have several departments and multiple applications tend to lose their grasp on their systems and data when they don’t make use of an Enterprise Data Model. Consequently, projects and troubleshooting can to take longer and cost more than necessary.
EDMs are used to ensure that everyone up, down and throughout the organization has a consistent and correct understanding. Even if your shop still has silo-ed applications, the EDM can help keep them from diverging and producing contradicting output.
What is a Conceptual Model?
A conceptual model depicts your high level business components and their relationships to each other.
What is a Logical Data Model?
A logical model may be derived from the conceptual model. The logical model adds details including specific attributes of the business components. It also specifies details such as what type of data each attribute is (i.e. text, number, date) and which attribute(s) uniquely identify an object. Sometimes conceptual and logical models are consolidated into one.
What is a Physical Data Model?
The physical data model is derived from the logical data model. It is the database design. This is the first of the three models (conceptual, logical, physical) that adds details specific to the database management system that you’re using. It gives you the details of the logical data model in the way that the specific database represents them. For example, a text attribute may be represented as a varchar2 up to 50 characters long. The physical data model is used to generate the data definition language (DDL) that will be run to create the database tables.
What is an Entity Relationship Diagram?
The entity-relationship diagram (ERD) is the graphical representation in which data models are typically delivered.
What is a Dimensional Model?
Dimensional modeling is often associated with data warehouses, business intelligence, and analytical data. The design concept is based facts (numbers like dollars or quantities) surrounded by dimensions (characteristics about the facts like regions or categories). A dimensional model consolidates data around answering specific questions and is often employed to access specific information very quickly, faster than it could be accessed without the dimensional design.