Chapter 9 View Design and Integration

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Outline Motivation for view design and integration View design with forms View integration

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Overview of View Design and Integration

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Sample Customer Order Form

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Form Analysis Steps

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Hierarchical Form Structure

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Entity Types for the Customer Order Form

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Attributes Added to the Entity Types

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Entity Relationship Diagram

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Consistency Rules for Relationship Cardinalities 1.In at least one direction, the maximum cardinality should be one for relationships connecting entity types derived from the same node (parent or child). 2.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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Sample Project Purchasing Form

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin ERD for the Project Purchase Form

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Sample Purchasing Form

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin ERD for the Purchasing Form

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin View Integration Combine individual views into a complete database design Incremental and parallel integration approaches

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Incremental Approach

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Parallel Approach

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Integration Strategy

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Precedence Example

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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

View Integration Examples

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Sample Invoice Form

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Incremental Integration Example The following 5 slides demonstrate the Incremental Integration process by integrating the Invoice Form with the ERD for Customer Order Form.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Form Hierarchy

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Identify entity types and attach attributes

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Integrated ERD (incremental)

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin ERD for the Invoice Form

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin Integrated ERD (Parallel)

© 2001 The McGraw-Hill Companies, Inc. All rights reserved. McGraw-Hill/Irwin 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.