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Lecture Business system development - Lecture 32: Course revision (Last lecture)

This chapter presents the following content: Logical database design, physical database design, deliverables and outcomes, normalization, transforming E-R diagrams into relations, the process of designing forms and reports,. | Business System Development CSC581 Lecture 32 Course Revision (Last lecture) 2 Logical Database Design Based upon the conceptual data model Four key steps Develop a logical data model for each known user interface for the application using normalization principles. Combine normalized data requirements from all user interfaces into one consolidated logical database model (view integration). Translate the conceptual E-R data model for the application into normalized data requirements. Compare the consolidated logical database design with the translated E-R model and produce one final logical database model for the application. Physical Database Design Based upon results of logical database design Key decisions Choosing storage format for each attribute from the logical database model Grouping attributes from the logical database model into physical records Arranging related records in secondary memory (hard disks and magnetic tapes) so that records can be stored, retrieved and updated | Business System Development CSC581 Lecture 32 Course Revision (Last lecture) 2 Logical Database Design Based upon the conceptual data model Four key steps Develop a logical data model for each known user interface for the application using normalization principles. Combine normalized data requirements from all user interfaces into one consolidated logical database model (view integration). Translate the conceptual E-R data model for the application into normalized data requirements. Compare the consolidated logical database design with the translated E-R model and produce one final logical database model for the application. Physical Database Design Based upon results of logical database design Key decisions Choosing storage format for each attribute from the logical database model Grouping attributes from the logical database model into physical records Arranging related records in secondary memory (hard disks and magnetic tapes) so that records can be stored, retrieved and updated rapidly Selecting media and structures for storing data to make access more efficient Deliverables and Outcomes Logical database design must account for every data element on a system input or output normalized relations are the primary deliverable Physical database design converting relations into database tables 6 Well-Structured Relation No redundancy, and data pertains to a single entity, an employee A Poorly Structured Relation Redundancies, because data pertains to a two entities, employees and the courses they take Normalization The process of converting complex data structures into simple, stable data structures First Normal From (1NF) Unique rows No multivalued attributes All relations are in 1NF 9 Normalization (cont.) Second Normal Form (2NF) Each nonprimary key attribute is identified by the whole key (called full functional dependency). Third Normal Form (3NF) Nonprimary key attributes do not depend on each other (i.e. no transitive dependencies). The result of .