data Modelling adn Entitity Relation Diagrams are pictorial representaion of all the selected tables ( with their columns , some copnstarints , constraints , ) relationship with other tables and type of relation ship ata glance .
Data Model Diagram is similar to this . it tells about the workflow of any user created application or procedure .
this is used by designers while designing any application . there is a seperate tool to prepare server model diagram , ER Diagrams , Functional Hierarchy Diagrams , Data Model Diagram