Database Processing: David M. Kroenke’s Chapter Five: Fundamentals, Design, and Implementation Chapter Five: Data Modeling with the Entity-Relationship Model Part Two DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

Strong Entity Patterns: 1:1 Strong Entity Relationships DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

Strong Entity Patterns: 1:1 Strong Entity Relationships ---- Non-identifying relationship, 0:0, 1:1 (min, max) DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

Strong Entity Patterns: 1:N Strong Entity Relationships Although this appears to be clearly 1:N, You can’t be sure that a department is in a single company because this form doesn’t show the relationship. ASK the user. OK, the user thinks … ask the student. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

Strong Entity Patterns: 1:N Strong Entity Relationships DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

Strong Entity Patterns: N:M Strong Entity Relationships Again this seems to be a 1:N relationship but … DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

Strong Entity Patterns: N:M Strong Entity Relationships … here we see a report from the other perspective. Here the form and report together let us know that there is an N:M relationship. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

Strong Entity Patterns: N:M Strong Entity Relationships Part should have a 0 above the crow’s foot. Note is provided due to ERWins deficiency Company-Department is a Strong Entity relationship, where as Company-Part is an ID-dependent relationship. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Association Pattern Note the Price column, which has been added. Includes Parts Includes companies Quotation is ID-dependent on both PART and COMPANY! It is not just a simple relation because it includes price! DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Association Pattern This is equivalent to saying that a Part must have a “PRICE”, but a company may not sell it. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Multivaled Attribute Pattern Classical multivalue dependency DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Multivaled Attribute Pattern Company:Phone 1:0, 1:N DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Multivaled Attribute Pattern N-Multivalued attributes breeds multiple ID-Dependent Entities DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Multivaled Attribute Pattern DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Archtype/Instance Pattern The archtype/instance pattern occurs when the ID-dependent child entity is the physical manisfestation (instance) of an abstract or logical parent: PAINTING : PRINT CLASS : SECTION YACHT_DESIGN : YACHT HOUSE_MODEL: HOUSE DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Archtype/Instance Pattern Note that these are true ID-dependent relationships - the identifier of the parent appears as part of the composite identifier of the ID-dependent child. DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

ID-Dependent Relationships: The Archtype/Instance Pattern Note the use of weak, but not ID-dependent children. Just because the ID:ClassName isn’t stated doesn’t mean there isn’t a way to determine it from the data. ClassDays, Time, Professor, SectionNumber are sufficient to identify the class! DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall

David M. Kroenke’s Database Processing Fundamentals, Design, and Implementation (10th Edition) End of Presentation: Chapter Five Part Two DAVID M. KROENKE’S DATABASE PROCESSING, 10th Edition © 2006 Pearson Prentice Hall