Database Architecture ClientServer Architecture Client module Run on
Database Architecture
Client/Server Architecture �Client module Run on a user workstation or personal computer Application programs and user interfaces ( Forms / GUIs) �Server module Data storage, access, search
Data models �Data abstraction Suppression of details of data organization and storage Different users perceive data at their preferred level of detail �Data model Used to describe the structure of a database � Data types, relationships and constraints � Basic operations for specifying retrievals and updates � Dynamic behavior Specify a set of valid user defined operations allowed on db objs COMPUTE_GPA on student object
Categories of data models �High level / Conceptual data model Provide concepts close to many users perceive data Use concepts such as entities, attributes and relationships Entity – represents a real world object / concept Attribute – some property that describes an entity Relationship – association among 2 / more entities � EMPLOYEE works in a DEPARTMENT �Representational / Implementation data model Relational data model , Network model, Hierarchical model Represent data using record structures – record based data models
ER diagram
Network model
�Low level / Physical data model Describe how data is stored on storage media – magnetic disks
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