SlideShare a Scribd company logo
1
© Prentice Hall, 2002
Chapter 4:Chapter 4:
The Enhanced E-R Model andThe Enhanced E-R Model and
Business RulesBusiness Rules
Modern Database Management
6th
Edition
Jeffrey A. Hoffer, Mary B. Prescott, Fred R.
McFadden
2Chapter 4
© Prentice Hall, 2002
Supertypes and SubtypesSupertypes and Subtypes
Subtype:Subtype: A subgrouping of the entities in an entity type
which has attributes that are distinct from those in other
subgroupings
Supertype:Supertype: An generic entity type that has a
relationship with one or more subtypes
Inheritance:Inheritance:
– Subtype entities inherit values of all attributes of the
supertype
– An instance of a subtype is also an instance of the
supertype
3Chapter 4
© Prentice Hall, 2002
Figure 4-1
Basic notation for
supertype/subtype
relationships
4Chapter 4
© Prentice Hall, 2002
Figure 4-2 -- Employee supertype with three subtypes
All employee subtypes
will have emp nbr, name,
address, and date-hired
Each employee subtype
will also have its own
attributes
5Chapter 4
© Prentice Hall, 2002
Relationships and SubtypesRelationships and Subtypes
Relationships at the supertype level indicate
that all subtypes will participate in the
relationship
The instances of a subtype may participate
in a relationship unique to that subtype. In
this situation, the relationship is shown at
the subtype level
6Chapter 4
© Prentice Hall, 2002
Figure 4-3 -- Supertype/subtype relationships in a hospital
Both outpatients and resident
patients are cared for by a
responsible physician
Only resident patients are
assigned to a bed
7Chapter 4
© Prentice Hall, 2002
Generalization andGeneralization and
SpecializationSpecialization
Generalization: The process of defining a
more general entity type from a set of more
specialized entity types. BOTTOM-UPBOTTOM-UP
Specialization: The process of defining
one or more subtypes of the supertype, and
forming supertype/subtype relationships.
TOP-DOWNTOP-DOWN
8Chapter 4
© Prentice Hall, 2002
Figure 4-4 – Example of generalization
(a) Three entity types: CAR, TRUCK, and MOTORCYCLE
All these types
of vehicles
have common
attributes
9Chapter 4
© Prentice Hall, 2002
Figure 4-4(b) – Generalization to VEHICLE supertype
So we put
the shared
attributes in
a supertype
Note: no subtype for motorcycle, since it has no unique attributes
10Chapter 4
© Prentice Hall, 2002
Figure 4-5 – Example of specialization
(a) Entity type PART
Only applies to
manufactured
parts
Applies only to purchased parts
11Chapter 4
© Prentice Hall, 2002
Figure 4-5(b) –
Specialization to MANUFACTURED PART and PURCHASED PART
Note: multivalued attribute was replaced by a relationship to another entity
Created 2 subtypes
12Chapter 4
© Prentice Hall, 2002
Constraints in Supertype/Constraints in Supertype/
Completeness ConstraintCompleteness Constraint
Completeness Constraints: Whether an
instance of a supertype must also be a
member of at least one subtype
– Total Specialization Rule: Yes (double line)
– Partial Specialization Rule: No (single line)
13Chapter 4
© Prentice Hall, 2002
Figure 4-6 – Examples of completeness constraints
(a) Total specialization rule
A patient must be either
an outpatient or a
resident patient
14Chapter 4
© Prentice Hall, 2002
Figure 4-6(b) – Partial specialization rule
A vehicle could be a
car, a truck, or neither
15Chapter 4
© Prentice Hall, 2002
Constraints in Supertype/Constraints in Supertype/
Disjointness constraintDisjointness constraint
Disjointness Constraints: Whether an
instance of a supertype may simultaneously
be a member of two (or more) subtypes.
– Disjoint Rule: An instance of the supertype can
be only ONE of the subtypes
– Overlap Rule: An instance of the supertype
could be more than one of the subtypes
16Chapter 4
© Prentice Hall, 2002
(a) Disjoint rule
Figure 4-7 – Examples of disjointness constraints
A patient can either be outpatient
or resident, but not both
17Chapter 4
© Prentice Hall, 2002
Figure 4-7(b) Overlap rule
A part may be
both purchased
and manufactured
18Chapter 4
© Prentice Hall, 2002
Constraints in Supertype/Constraints in Supertype/
Subtype DiscriminatorsSubtype Discriminators
Subtype Discriminator: An attribute of the
supertype whose values determine the target
subtype(s)
– Disjoint – a simple attribute with alternative values to
indicate the possible subtypes
– Overlapping – a composite attribute whose subparts
pertain to different subtypes. Each subpart contains a
boolean value to indicate whether or not the instance
belongs to the associated subtype
19Chapter 4
© Prentice Hall, 2002
Figure 4-8 – Introducing a subtype discriminator (disjoint rule)
A simple attribute with
different possible values
indicating the subtype
20Chapter 4
© Prentice Hall, 2002
Figure 4-9 – Subtype discriminator (overlap rule)
A composite attribute
with sub-attributes
indicating “yes” or “no”
to determine whether it
is of each subtype
21Chapter 4
© Prentice Hall, 2002
Figure 4-10 – Example of supertype/subtype hierarchy
22Chapter 4
© Prentice Hall, 2002
Entity ClustersEntity Clusters
EER diagrams are difficult to read when
there are too many entities and relationships
Solution: group entities and relationships
into entity clusters
Entity cluster: set of one or more entity
types and associated relationships grouped
into a single abstract entity type
23Chapter 4
© Prentice Hall, 2002
Figure 4-13(a) –
Possible entity clusters
for Pine Valley Furniture
Related
groups of
entities could
become
clusters
24Chapter 4
© Prentice Hall, 2002
Figure 4-13(b) – EER diagram of PVF entity clusters
More readable,
isn’t it?
25Chapter 4
© Prentice Hall, 2002
Business rulesBusiness rules
 Statements that define or constrain some aspect of the
business.
 Constraints can impact:
– Structure (definition, domain, relationship)
– Behavior (operational constraints)
 Classification of business rules:
– Derivation – rule derived from other knowledge
– Structural assertion – rule expressing static structure
– Action assertion – rule expressing constraints/control of
organizational actions
26Chapter 4
© Prentice Hall, 2002
Figure 4-15 –
EER depiction of
business rules
classification
Source: adapted from GUIDE Business Rules Project, 1997.
27Chapter 4
© Prentice Hall, 2002
Action Assertion ClassificationsAction Assertion Classifications
 Result
– Condition – IF/THEN rule
– Integrity constraint – must always be true
– Authorization – privilege statement
 Form
– Enabler – leads to creation of new object
– Timer – allows or disallows an action
– Executive – executes one or more actions
 Rigor
– Controlling – something must or must not happen
– Influencing – guideline for which a notification must
occur
28Chapter 4
© Prentice Hall, 2002
Stating an Action AssertionStating an Action Assertion
Anchor Object – an object on which actions
are limited
Action – creation, deletion, update, or read
Corresponding Objects – an object
influencing the ability to perform an action
on another business rule
Action assertion will identify corresponding objects thatAction assertion will identify corresponding objects that
constrain the ability to perform actions on anchor objectsconstrain the ability to perform actions on anchor objects
29Chapter 4
© Prentice Hall, 2002
Figure 4-16 – Data model segment for class scheduling
30Chapter 4
© Prentice Hall, 2002
Figure 4-17 – Business Rule 1: For a faculty member to be assigned
to teach a section of a course, the faculty member must be qualified to
teach the course for which that section is scheduled
Action assertion
Anchor object
Corresponding object
Corresponding object
In this case, the
action assertion
is a RRestriction
31Chapter 4
© Prentice Hall, 2002
Figure 4-18 –Business Rule 2: For a faculty member to be assigned to
teach a section of a course, the faculty member must not be assigned to
teach a total of more than three course sections
Action assertionAnchor object
Corresponding object
In this case, the
action assertion
is an
UUpper LIMLIMit

More Related Content

PPT
Er & eer to relational mapping
PPT
Object Oriented Analysis and Design
PPT
Lecture 04 normalization
PPTX
Entity Relationship Modelling
PPT
Modern database management jeffrey a. hoffer, mary b. prescott,
PPT
Requirements analysis
PPTX
Functional dependancy
PPT
Unit 1( modelling concepts & class modeling)
Er & eer to relational mapping
Object Oriented Analysis and Design
Lecture 04 normalization
Entity Relationship Modelling
Modern database management jeffrey a. hoffer, mary b. prescott,
Requirements analysis
Functional dependancy
Unit 1( modelling concepts & class modeling)

What's hot (20)

PPTX
Enhanced ER(database)
PPT
Databases: Normalisation
PPTX
Modeling- Object, Dynamic and Functional
PDF
Mapping ER and EER Model
PPTX
PDF
Enhanced Entity-Relationship (EER) Modeling
PPT
Architectural Design in Software Engineering SE10
PPT
Relational algebra operations
PDF
PPT
Lecture 1 data structures and algorithms
PDF
Normalization
PPT
Normlaization
PPTX
Erd practice exercises
PPTX
EER modeling
PPT
Normalization
PPT
PPT
The relational database model
PDF
Lex and Yacc.pdf
PPTX
Data models
PPTX
Object oriented modeling and design
Enhanced ER(database)
Databases: Normalisation
Modeling- Object, Dynamic and Functional
Mapping ER and EER Model
Enhanced Entity-Relationship (EER) Modeling
Architectural Design in Software Engineering SE10
Relational algebra operations
Lecture 1 data structures and algorithms
Normalization
Normlaization
Erd practice exercises
EER modeling
Normalization
The relational database model
Lex and Yacc.pdf
Data models
Object oriented modeling and design
Ad

Similar to The Database Environment Chapter 4 (20)

PPTX
Lecture-6(a-b).pptx
PPT
Ch 4 E E R Biz Rules
PPT
The Database Environment Chapter 14
PPT
Lecture-8(a-b).ppt xx intro to management
PPT
The Database Environment Chapter 3
PPT
ERD Model in database comsats university.ppt
PPT
Data mining lecture 4 taught at Stanford
PPT
Ch 5 O O Data Modeling
PPT
modern database manage hoffer_mdm_pp_ch03.ppt
PPT
Object Oriented Analysis and Design with UML2 part2
PPT
Ch 5 O O Data Modeling Class
PPT
PPT
21792 relational database managementsystem
PDF
CS8592 Object Oriented Analysis & Design - UNIT IV
PDF
AN ENVIRONMENT FOR NON-DUPLICATE TEST GENERATION FOR WEB BASED APPLICATION
PPTX
Sadcw 7e chapter04(1)
PPTX
Sadcw 7e chapter04_recorded
PPT
Practical dimensions
PPT
M03_1_StructuralDiagrams in unified modeling language
PPT
M03_1_Structur alDiagrams.ppt
Lecture-6(a-b).pptx
Ch 4 E E R Biz Rules
The Database Environment Chapter 14
Lecture-8(a-b).ppt xx intro to management
The Database Environment Chapter 3
ERD Model in database comsats university.ppt
Data mining lecture 4 taught at Stanford
Ch 5 O O Data Modeling
modern database manage hoffer_mdm_pp_ch03.ppt
Object Oriented Analysis and Design with UML2 part2
Ch 5 O O Data Modeling Class
21792 relational database managementsystem
CS8592 Object Oriented Analysis & Design - UNIT IV
AN ENVIRONMENT FOR NON-DUPLICATE TEST GENERATION FOR WEB BASED APPLICATION
Sadcw 7e chapter04(1)
Sadcw 7e chapter04_recorded
Practical dimensions
M03_1_StructuralDiagrams in unified modeling language
M03_1_Structur alDiagrams.ppt
Ad

More from Jeanie Arnoco (20)

PPT
The Database Environment Chapter 15
PPT
The Database Environment Chapter 13
PPT
The Database Environment Chapter 12
PPT
The Database Environment Chapter 11
PPT
The Database Environment Chapter 10
PPT
The Database Environment Chapter 9
PPT
The Database Environment Chapter 8
PPT
The Database Environment Chapter 7
PPT
The Database Environment Chapter 6
PPT
The Database Environment Chapter 5
PPT
The Database Environment Chapter 2
PPT
The Database Environment Chapter 1
PPT
Introduction to BOOTSTRAP
PPT
Introduction to programming using Visual Basic 6
PPTX
Hacking and Online Security
PPTX
(CAR)Cordillera Administrative Region
PPTX
Quick sort-Data Structure
PPTX
Quality Gurus Student
PPT
QUALITY STANDARDS
PPTX
Partnering for Competition: External Partnership
The Database Environment Chapter 15
The Database Environment Chapter 13
The Database Environment Chapter 12
The Database Environment Chapter 11
The Database Environment Chapter 10
The Database Environment Chapter 9
The Database Environment Chapter 8
The Database Environment Chapter 7
The Database Environment Chapter 6
The Database Environment Chapter 5
The Database Environment Chapter 2
The Database Environment Chapter 1
Introduction to BOOTSTRAP
Introduction to programming using Visual Basic 6
Hacking and Online Security
(CAR)Cordillera Administrative Region
Quick sort-Data Structure
Quality Gurus Student
QUALITY STANDARDS
Partnering for Competition: External Partnership

Recently uploaded (20)

PDF
01-Introduction-to-Information-Management.pdf
PDF
RMMM.pdf make it easy to upload and study
PDF
102 student loan defaulters named and shamed – Is someone you know on the list?
PDF
Sports Quiz easy sports quiz sports quiz
PDF
Physiotherapy_for_Respiratory_and_Cardiac_Problems WEBBER.pdf
PDF
Chapter 2 Heredity, Prenatal Development, and Birth.pdf
PPTX
school management -TNTEU- B.Ed., Semester II Unit 1.pptx
PDF
STATICS OF THE RIGID BODIES Hibbelers.pdf
PDF
Insiders guide to clinical Medicine.pdf
PDF
ANTIBIOTICS.pptx.pdf………………… xxxxxxxxxxxxx
PPTX
1st Inaugural Professorial Lecture held on 19th February 2020 (Governance and...
PPTX
Lesson notes of climatology university.
PDF
BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH 9 GLOBAL SUCCESS - CẢ NĂM - BÁM SÁT FORM Đ...
PPTX
Final Presentation General Medicine 03-08-2024.pptx
PDF
VCE English Exam - Section C Student Revision Booklet
PDF
Abdominal Access Techniques with Prof. Dr. R K Mishra
PDF
O7-L3 Supply Chain Operations - ICLT Program
PPTX
Pharma ospi slides which help in ospi learning
PDF
Classroom Observation Tools for Teachers
PPTX
PPH.pptx obstetrics and gynecology in nursing
01-Introduction-to-Information-Management.pdf
RMMM.pdf make it easy to upload and study
102 student loan defaulters named and shamed – Is someone you know on the list?
Sports Quiz easy sports quiz sports quiz
Physiotherapy_for_Respiratory_and_Cardiac_Problems WEBBER.pdf
Chapter 2 Heredity, Prenatal Development, and Birth.pdf
school management -TNTEU- B.Ed., Semester II Unit 1.pptx
STATICS OF THE RIGID BODIES Hibbelers.pdf
Insiders guide to clinical Medicine.pdf
ANTIBIOTICS.pptx.pdf………………… xxxxxxxxxxxxx
1st Inaugural Professorial Lecture held on 19th February 2020 (Governance and...
Lesson notes of climatology university.
BÀI TẬP BỔ TRỢ 4 KỸ NĂNG TIẾNG ANH 9 GLOBAL SUCCESS - CẢ NĂM - BÁM SÁT FORM Đ...
Final Presentation General Medicine 03-08-2024.pptx
VCE English Exam - Section C Student Revision Booklet
Abdominal Access Techniques with Prof. Dr. R K Mishra
O7-L3 Supply Chain Operations - ICLT Program
Pharma ospi slides which help in ospi learning
Classroom Observation Tools for Teachers
PPH.pptx obstetrics and gynecology in nursing

The Database Environment Chapter 4

  • 1. 1 © Prentice Hall, 2002 Chapter 4:Chapter 4: The Enhanced E-R Model andThe Enhanced E-R Model and Business RulesBusiness Rules Modern Database Management 6th Edition Jeffrey A. Hoffer, Mary B. Prescott, Fred R. McFadden
  • 2. 2Chapter 4 © Prentice Hall, 2002 Supertypes and SubtypesSupertypes and Subtypes Subtype:Subtype: A subgrouping of the entities in an entity type which has attributes that are distinct from those in other subgroupings Supertype:Supertype: An generic entity type that has a relationship with one or more subtypes Inheritance:Inheritance: – Subtype entities inherit values of all attributes of the supertype – An instance of a subtype is also an instance of the supertype
  • 3. 3Chapter 4 © Prentice Hall, 2002 Figure 4-1 Basic notation for supertype/subtype relationships
  • 4. 4Chapter 4 © Prentice Hall, 2002 Figure 4-2 -- Employee supertype with three subtypes All employee subtypes will have emp nbr, name, address, and date-hired Each employee subtype will also have its own attributes
  • 5. 5Chapter 4 © Prentice Hall, 2002 Relationships and SubtypesRelationships and Subtypes Relationships at the supertype level indicate that all subtypes will participate in the relationship The instances of a subtype may participate in a relationship unique to that subtype. In this situation, the relationship is shown at the subtype level
  • 6. 6Chapter 4 © Prentice Hall, 2002 Figure 4-3 -- Supertype/subtype relationships in a hospital Both outpatients and resident patients are cared for by a responsible physician Only resident patients are assigned to a bed
  • 7. 7Chapter 4 © Prentice Hall, 2002 Generalization andGeneralization and SpecializationSpecialization Generalization: The process of defining a more general entity type from a set of more specialized entity types. BOTTOM-UPBOTTOM-UP Specialization: The process of defining one or more subtypes of the supertype, and forming supertype/subtype relationships. TOP-DOWNTOP-DOWN
  • 8. 8Chapter 4 © Prentice Hall, 2002 Figure 4-4 – Example of generalization (a) Three entity types: CAR, TRUCK, and MOTORCYCLE All these types of vehicles have common attributes
  • 9. 9Chapter 4 © Prentice Hall, 2002 Figure 4-4(b) – Generalization to VEHICLE supertype So we put the shared attributes in a supertype Note: no subtype for motorcycle, since it has no unique attributes
  • 10. 10Chapter 4 © Prentice Hall, 2002 Figure 4-5 – Example of specialization (a) Entity type PART Only applies to manufactured parts Applies only to purchased parts
  • 11. 11Chapter 4 © Prentice Hall, 2002 Figure 4-5(b) – Specialization to MANUFACTURED PART and PURCHASED PART Note: multivalued attribute was replaced by a relationship to another entity Created 2 subtypes
  • 12. 12Chapter 4 © Prentice Hall, 2002 Constraints in Supertype/Constraints in Supertype/ Completeness ConstraintCompleteness Constraint Completeness Constraints: Whether an instance of a supertype must also be a member of at least one subtype – Total Specialization Rule: Yes (double line) – Partial Specialization Rule: No (single line)
  • 13. 13Chapter 4 © Prentice Hall, 2002 Figure 4-6 – Examples of completeness constraints (a) Total specialization rule A patient must be either an outpatient or a resident patient
  • 14. 14Chapter 4 © Prentice Hall, 2002 Figure 4-6(b) – Partial specialization rule A vehicle could be a car, a truck, or neither
  • 15. 15Chapter 4 © Prentice Hall, 2002 Constraints in Supertype/Constraints in Supertype/ Disjointness constraintDisjointness constraint Disjointness Constraints: Whether an instance of a supertype may simultaneously be a member of two (or more) subtypes. – Disjoint Rule: An instance of the supertype can be only ONE of the subtypes – Overlap Rule: An instance of the supertype could be more than one of the subtypes
  • 16. 16Chapter 4 © Prentice Hall, 2002 (a) Disjoint rule Figure 4-7 – Examples of disjointness constraints A patient can either be outpatient or resident, but not both
  • 17. 17Chapter 4 © Prentice Hall, 2002 Figure 4-7(b) Overlap rule A part may be both purchased and manufactured
  • 18. 18Chapter 4 © Prentice Hall, 2002 Constraints in Supertype/Constraints in Supertype/ Subtype DiscriminatorsSubtype Discriminators Subtype Discriminator: An attribute of the supertype whose values determine the target subtype(s) – Disjoint – a simple attribute with alternative values to indicate the possible subtypes – Overlapping – a composite attribute whose subparts pertain to different subtypes. Each subpart contains a boolean value to indicate whether or not the instance belongs to the associated subtype
  • 19. 19Chapter 4 © Prentice Hall, 2002 Figure 4-8 – Introducing a subtype discriminator (disjoint rule) A simple attribute with different possible values indicating the subtype
  • 20. 20Chapter 4 © Prentice Hall, 2002 Figure 4-9 – Subtype discriminator (overlap rule) A composite attribute with sub-attributes indicating “yes” or “no” to determine whether it is of each subtype
  • 21. 21Chapter 4 © Prentice Hall, 2002 Figure 4-10 – Example of supertype/subtype hierarchy
  • 22. 22Chapter 4 © Prentice Hall, 2002 Entity ClustersEntity Clusters EER diagrams are difficult to read when there are too many entities and relationships Solution: group entities and relationships into entity clusters Entity cluster: set of one or more entity types and associated relationships grouped into a single abstract entity type
  • 23. 23Chapter 4 © Prentice Hall, 2002 Figure 4-13(a) – Possible entity clusters for Pine Valley Furniture Related groups of entities could become clusters
  • 24. 24Chapter 4 © Prentice Hall, 2002 Figure 4-13(b) – EER diagram of PVF entity clusters More readable, isn’t it?
  • 25. 25Chapter 4 © Prentice Hall, 2002 Business rulesBusiness rules  Statements that define or constrain some aspect of the business.  Constraints can impact: – Structure (definition, domain, relationship) – Behavior (operational constraints)  Classification of business rules: – Derivation – rule derived from other knowledge – Structural assertion – rule expressing static structure – Action assertion – rule expressing constraints/control of organizational actions
  • 26. 26Chapter 4 © Prentice Hall, 2002 Figure 4-15 – EER depiction of business rules classification Source: adapted from GUIDE Business Rules Project, 1997.
  • 27. 27Chapter 4 © Prentice Hall, 2002 Action Assertion ClassificationsAction Assertion Classifications  Result – Condition – IF/THEN rule – Integrity constraint – must always be true – Authorization – privilege statement  Form – Enabler – leads to creation of new object – Timer – allows or disallows an action – Executive – executes one or more actions  Rigor – Controlling – something must or must not happen – Influencing – guideline for which a notification must occur
  • 28. 28Chapter 4 © Prentice Hall, 2002 Stating an Action AssertionStating an Action Assertion Anchor Object – an object on which actions are limited Action – creation, deletion, update, or read Corresponding Objects – an object influencing the ability to perform an action on another business rule Action assertion will identify corresponding objects thatAction assertion will identify corresponding objects that constrain the ability to perform actions on anchor objectsconstrain the ability to perform actions on anchor objects
  • 29. 29Chapter 4 © Prentice Hall, 2002 Figure 4-16 – Data model segment for class scheduling
  • 30. 30Chapter 4 © Prentice Hall, 2002 Figure 4-17 – Business Rule 1: For a faculty member to be assigned to teach a section of a course, the faculty member must be qualified to teach the course for which that section is scheduled Action assertion Anchor object Corresponding object Corresponding object In this case, the action assertion is a RRestriction
  • 31. 31Chapter 4 © Prentice Hall, 2002 Figure 4-18 –Business Rule 2: For a faculty member to be assigned to teach a section of a course, the faculty member must not be assigned to teach a total of more than three course sections Action assertionAnchor object Corresponding object In this case, the action assertion is an UUpper LIMLIMit