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Chapter 9

Chapter 9. View Design and Integration. Outline. Motivation for view design and integration View design with forms View integration. Why View Design and Integration ?. Database complexity reflects organizational complexity Time-consuming and labor-intensive process

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Chapter 9

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  1. Chapter 9 View Design and Integration

  2. Outline • Motivation for view design and integration • View design with forms • View integration McGraw-Hill/Irwin

  3. Why View Design and Integration? • Database complexity reflects organizational complexity • Time-consuming and labor-intensive process • Collect requirements from different user groups • Involves coordination among designer team McGraw-Hill/Irwin

  4. Motivation for View Design and Integration As the “divide and conquer” strategy is used to manage complexity, View Design and Integration is an approach to managing complexity of the database design effort. McGraw-Hill/Irwin

  5. Overview of View Design and Integration McGraw-Hill/Irwin

  6. View Design with Forms • Important source of database requirements • Reverse the process described in the first part of the book • Derive an ERD that is consistent with the form • Five step procedure McGraw-Hill/Irwin

  7. Sample Customer Order Form McGraw-Hill/Irwin

  8. Form Analysis • Create an ERD to represent a form • ERD supports form and other anticipated processing • ERD should be consistent with the form • ERD is a view of the database McGraw-Hill/Irwin

  9. Form Analysis Steps McGraw-Hill/Irwin

  10. Step 1: Define Form Structure • Construct a hierarchy that depicts the form structure. • Most forms consist of a simple hierarchy where the main form is the parent and the subform is the child. • Complex forms can have parallel subforms and more levels in the hierarchy. McGraw-Hill/Irwin

  11. Hierarchical Form Structure McGraw-Hill/Irwin

  12. Step 2: Identify Entity Types • Split each node in the hierarchical structure into one or more entity types. • Make an entity type if the form field is a potential primary key and there are other associated fields in the form. McGraw-Hill/Irwin

  13. Entity Types for the Customer Order Form McGraw-Hill/Irwin

  14. Step 3: Attach Attributes • Attach attributes to the entity types identified in the previous step • Group together fields that are associated with the primary keys found in Step 2 • Form fields close together may belong in the same entity type McGraw-Hill/Irwin

  15. Attributes Added to the Entity Types McGraw-Hill/Irwin

  16. Step 4: Add Relationships • Relationships involving the form entity type • Form entity type contains the form's primary key • Relationships between the form entity type and other entity types derived from the parent node: usually 1-M. • Add a relationship to connect the form entity type to an entity type in the child node • Add relationships to connect entity types derived from the child node if not already connected McGraw-Hill/Irwin

  17. Entity Relationship Diagram McGraw-Hill/Irwin

  18. Step 5: Check Completeness and Consistency • Check the ERD for consistency and completeness with the form structure. • The ERD should contain minimum and maximum cardinalities for all relationships, a primary key for all entity types, and a name for all relationships. McGraw-Hill/Irwin

  19. Consistency Rules for Relationship Cardinalities • In at least one direction, the maximum cardinality should be one for relationships connecting entity types derived from the same node (parent or child). • In at least one direction, the maximum cardinality should be greater than one for relationships connecting entity types derived from nodes on different levels of the form hierarchy. McGraw-Hill/Irwin

  20. Analysis of M-Way Relationships using Forms • Choice between M-way and binary relationships can be difficult. • Data entry forms provide a context to understand M-way relationships. • An M-way relationship may be needed if a form shows a data entry pattern involving three entity types. McGraw-Hill/Irwin

  21. Sample Project Purchasing Form McGraw-Hill/Irwin

  22. ERD for the Project Purchase Form McGraw-Hill/Irwin

  23. Sample Purchasing Form McGraw-Hill/Irwin

  24. ERD for the Purchasing Form McGraw-Hill/Irwin

  25. View Integration • Combine individual views into a complete database design • Incremental and parallel integration approaches McGraw-Hill/Irwin

  26. Incremental Approach McGraw-Hill/Irwin

  27. Parallel Approach McGraw-Hill/Irwin

  28. Integration Strategy McGraw-Hill/Irwin

  29. Precedence Relationships • Form A precedes form B if form A must be complete before form B • Preceding forms typically provide data for subsequent forms • Place forms with precedence relationships in the same view subset McGraw-Hill/Irwin

  30. Precedence Example McGraw-Hill/Irwin

  31. Resolving Synonyms and Homonyms • Synonym: spelled differently but have the same meaning • Homonym: same sound and often the same spelling but different meaning • Forms provide a context to resolve • Major part of standardizing a vocabulary McGraw-Hill/Irwin

  32. View Integration Examples

  33. Sample Invoice Form McGraw-Hill/Irwin

  34. Incremental Integration Example • The following 5 slides demonstrate the Incremental Integration process by integrating the Invoice Form with the ERD for Customer Order Form. McGraw-Hill/Irwin

  35. Form Hierarchy McGraw-Hill/Irwin

  36. Identify entity types and attach attributes McGraw-Hill/Irwin

  37. List the form fields that match existing entity types • Order No matches the Order entity type. • Customer No, Customer Name, Address, City, State, and Zip match the Customer entity type. • Product No, Description, and Unit Price match the Product entity type. McGraw-Hill/Irwin

  38. Analyze homonyms • Revise the Customer entity type with two sets of address fields: billing address fields and shipping address fields. • Add shipping address fields to the Invoice entity type. • Create a new entity type (ShipAddress) with the shipping address fields. McGraw-Hill/Irwin

  39. Integrated ERD (incremental) McGraw-Hill/Irwin

  40. Parallel Integration Example • The difference between the parallel and incremental approaches is that integration occurs later in the parallel approach. • For the parallel approach, ERDs for forms must be constructed before merging. McGraw-Hill/Irwin

  41. ERD for the Invoice Form McGraw-Hill/Irwin

  42. Integrated ERD (Parallel) McGraw-Hill/Irwin

  43. Summary • View design and integration is an important skill for designing large databases. • Manage complexity of large development efforts. • The result of form analysis is an ERD that is a view of the database. • Two approaches for View Integration, incremental and parallel. McGraw-Hill/Irwin

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