tailieunhanh - Lecture Business system development - Lecture 15: Designing databases

In this lecture, we will: Define key database design terms, explain the role of database design in the IS development process, transform E-R or class diagrams into normalized relations, merge normalized relations from separate user views into a consolidated set of well-structured relations. | Business System Development CSC581 Lecture 15 Designing Databases 2 Summary of the previous lecture In previous lecture, we : Defined four types of business rules. Compared the capabilities of class diagrams vs. E-R diagrams. Related data modeling to process and logic modeling. Outlines We today’s lecture we will: Define key database design terms. Explain the role of database design in the IS development process. Transform E-R or class diagrams into normalized relations. Merge normalized relations from separate user views into a consolidated set of well-structured relations. Choose storage formats for fields. Translate well-structured relations into database tables. Explain when to use different types of file organizations. Describe the purpose and appropriate use of indexes. 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 | Business System Development CSC581 Lecture 15 Designing Databases 2 Summary of the previous lecture In previous lecture, we : Defined four types of business rules. Compared the capabilities of class diagrams vs. E-R diagrams. Related data modeling to process and logic modeling. Outlines We today’s lecture we will: Define key database design terms. Explain the role of database design in the IS development process. Transform E-R or class diagrams into normalized relations. Merge normalized relations from separate user views into a consolidated set of well-structured relations. Choose storage formats for fields. Translate well-structured relations into database tables. Explain when to use different types of file organizations. Describe the purpose and appropriate use of indexes. 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 .