chapter 4 the semantic object model david m. kroenke database processing © 2000 prentice hall
TRANSCRIPT
Chapter 4The Semantic Object Model
David M. Kroenke
Database Processing
© 2000 Prentice Hall
Chapter 4
© 2000 Prentice Hall
Semantic Objects
“a named collection of attributes that sufficiently describes a distinct entity”
• Student• Customer• Employee
Page 74
Attributes“define the characteristics of
semantic objects”
Page 75Figure 4-2a © 2000 Prentice Hall
Attribute Cardinality“indicates the minimum or maximum number
of instances of the attribute that must exist in order for the object to be valid”
Page 76Figure 4-2b © 2000 Prentice Hall
Object Instances“the occurrence of a particular
semantic object”
Page 77Figure 4-3 © 2000 Prentice Hall
Chapter 4
© 2000 Prentice Hall
Object Identifier
“one or more object attributes that the users employ to identify object instances”
Example: CustomerID for Customer
Page 78
Chapter 4
© 2000 Prentice Hall
Domain
“a description of an attribute’s possible values”
Page 78
Semantic Object View“the portion of an object that is
visible to a particular application; view”
Page 79Figure 4-4 © 2000 Prentice Hall
Chapter 4
© 2000 Prentice Hall
Highline UniversityAdministration Database
• Objects:– College– Department– Professor– Student
Page 80
Semantic Object Diagrams
Page 85Figure 4-13 (1) © 2000 Prentice Hall
Semantic Object Diagrams
Page 85Figure 4-13 (2) © 2000 Prentice Hall
Semantic Object Diagrams
Page 85Figure 4-13 (3) © 2000 Prentice Hall
Semantic Object Diagrams
Page 85Figure 4-13 (4) © 2000 Prentice Hall
Semantic Object Specifications
Page 86Figure 4-14 (1) © 2000 Prentice Hall
Semantic Object Specifications
Page 86Figure 4-14 (2) © 2000 Prentice Hall
Semantic Object Specifications
Page 86Figure 4-14 (3) © 2000 Prentice Hall
Semantic Object Specifications
Page 86Figure 4-14 (4) © 2000 Prentice Hall
Chapter 4
© 2000 Prentice Hall
Domain Types
• Formula• Group• Simple• Semantic Object
Page 87
Domain Specifications
Page 87Figure 4-14b © 2000 Prentice Hall
Simple Objects“contain only single-value, nonobject
attributes”
Page 89Figure 4-15 © 2000 Prentice Hall
Composite Objects“contain one or more multi-value,
nonobject attributes”
Page 89Figure 4-16 © 2000 Prentice Hall
Composite Object with Nested Groups
Page 89Figure 4-18 © 2000 Prentice Hall
Hybrid Objects
“combinations of objects of two types”
Page 89Figure 4-22 © 2000 Prentice Hall
Association Objects“relate two (or more) objects and
store data that are peculiar to that relationship”
Page 99Figure 4-26b © 2000 Prentice Hall
Association Object Example
Page 100Figure 4-27b © 2000 Prentice Hall
Subtype Object
Page 101Figure 4-28 © 2000 Prentice Hall
Archetype/Version Object
Page 104Figure 4-31 © 2000 Prentice Hall
Semantic vs. E-R Model
Page 105Figure 4-33 © 2000 Prentice Hall
Semantic vs. E-R Model
Page 105Figure 4-34 © 2000 Prentice Hall