Explain different types of Conceptual Model? ( Logical Data Model, Physical Data Model)

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 Logical Data Model

A logical data model defines the information in as much structure as possible, without observing how it will be physically achieved in the database. The primary objective of logical data modeling is to document the business data structures, processes, rules, and relationships by a single view - the logical data model.

Features of a logical data model

  • It involves all entities and relationships among them.
  • All attributes for each entity are specified.
  • The primary key for each entity is stated.
  • Referential Integrity is specified (FK Relation).


The phase for designing the logical data model which is as follows:

  • Specify primary keys for all entities.
  •  List the relationships between different entities.
  • List all attributes for each entity.
  • Normalization.
  • No data types are listed

                                      Example of Logical data model




Physical Data Model
  • The physical data model describes how the model will be presented in the database. A physical database model demonstrates all table structures, column names, data types, constraints, primary key, foreign key, and relationships between tables. 
  • The purpose of physical data modeling is the mapping of the logical data model to the physical structures of the RDBMS system hosting the data warehouse. 
  • This contains defining physical RDBMS structures, such as tables and data types to use when storing the information. 
  • It may also include the definition of new data structures for enhancing query performance.

Characteristics of a physical data model
  • Specification of all tables and columns.
  • Foreign keys are used to recognize relationships between tables.

The steps for physical data model design are as follows:
  • Convert entities to tables.
  • Convert relationships to foreign keys.
  • Convert attributes to columns.


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