After all business requirements have been gathered for a proposed database, they must be modeled. Basically, data modeling act like a bridge between business needs and system requirements
Two types of data modeling are as follows:
- Logical Modeling
- Physical Modeling
It involves gathering information about business processes, entities, attributes for each entity and relationship among the entities. The deliverables of logical modeling include E-R(Entity – Relationship) diagrams, Business Process diagrams. This model is highly normalized.
It involves actual design of the database according to the requirements that were established during logical modeling. It deals with the conversion of logical or business model, into a relational data model.
It involves gathering the schema for tables, indexes, default and check constraints, and views for the application. This model include data types for each attribute and can be normalized or de-normalized.
Understanding the difference between logical and phyical modeling will help you build better organized and more effective database systems.