Download Conceptual Design versus Logical Design

Conceptual Design versus
Logical Design
Conceptual Data Design
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Prepared at beginning of project
High level view of how the client sees the data
Top down process
Not concerned with details
Normally prepared using brainstorming approach
Identification of Entities, Attributes and
Relationships represented using Entity
Relationship Diagram
• ERD is constantly modified as project progresses
and more is learnt about application’s data
Logical Data Design
• Detailed representation of application’s data
• Bottom-up process
• Purpose of logical data design is to represent
application data in the form of related 2dimensional relations which will correspond to
the tables created in a relational database
• Details obtained by analysing representative
samples of application’s user views or
prototyping user views
User View
• A user view is a view of the data presented by the
application to the user, i.e. a set of requirements
that are necessary to support the operations of a
particular user
• User views may include: input screen, output
screen, input form, detailed report, summary report
• User view should present sample data
• User view may be either a prototype or an actual
sample
• Should collect a representative sample of user
views from different areas in the application
• Technique of normalization is applied to each user
view to identify relations (i.e. tables)