1. University of Milano Bicocca, Italy Carlo Batini
Course in Data Base Design
Conceptual Design: qualities and methods

2. Introduction to strategies and qualities Motivating examples

3. Requirements “not toy example”
Students of a University attend courses, and pass them. Courses have a last name, a first name and a year of enrollment. Students have an ID, a Last Name and First Name. For Chinese Students we want to represent City of Birth and Region of Birth. For Foreign Students we want to represent the Country of Birth and the Continent of Birth. A Course passed by a Student has a grade and a date. Courses are taught by professors. Professors have a last name and a first name. They may be Associate Professors or Full professors, only for Full Professors we are interested to the City of Birth, with name and region. Every professor belongs to a Department. Departments have a Name and an address.

4. Example of complex step that cannot be performed“one shot”
Students of a University attend courses, and pass them. Courses have a last name, a first name and a year of enrollment. Students have an ID, a Last Name and First Name. For Chinese Students we want to represent City of Birth and Region of Birth. For Foreign Students we want to represent the Country of Birth and the Continent of Birth. A Course passed by a Student has a grade and a date. Courses are taught by professors. Professors have a last name and a first name. They may be Associate Professors or Full professors, only for Full Professors we are interested to the City of Birth, with name and region. Every professor belongs to a Department. Departments have a Name and an address.
Database Design
1. Student (Student Id, Last Name, First Name, Type)
2. Course (Course Id, Year of Enrollment)
3. Enrolled in (Student Id, Course Id)
4. Passed (Student Id, Course Id, Grade, Date)
5. Professor (Last Name, First Name, Type, Department Name)
6. Department (Name, Address)
7. Full Professor (Last Name, First Name, City of Birth)
8. City (Name, Region)
9. Foreign Student (Student Id, Country)
10. Chinese Student (Student Id, City of Birth)
11. Country (Name, Continent)

5. First strategy: two phases instead of one phase (divide et impera)

6. Phase 1 Phase 2 Phase 1 - Conceptual Design Phase 2 - Logical Design
Students of a University attend courses, and pass them. Courses have a last name, a first name and a year of enrollment. Students have an ID, a Last Name and First Name. For Chinese Students we want to represent City of Birth and Region of Birth. For Foreign Students we want to represent the Country of Birth and the Continent of Birth. A Course passed by a Student has a grade and a date. Courses are taught by professors. Professors have a last name and a first name. They may be Associate Professors or Full professors, only for Full Professors we are interested to the City of Birth, with name and region. Every professor belongs to a Department. Departments have a Name and an address.
First Name
Last Name
Born in
one
many ID
Teach
Name
Region
Associate
Professor
Full Professor
Belongs to
Address
Year of Enrollment
Passed
Enrolled in
Grade
Date
Chinese St.
Foreign St.
Born
Continent
Department
Country
Student
City
Course
First Name
Last Name
Born in
one
many ID
Teach
Name
Region
Associate
Professor
Full Professor
Belongs to
Address
Year of Enrollment
Passed
Enrolled in
Grade
Date
Chinese St.
Foreign St.
Born
Continent
Department
Country
Student
City
Course
Phase 1 - Conceptual Design
Phase 1
1. Student (Student Id, Last Name, First Name, Type)
2. Course (Course Id, Year of Enrollment)
3. Enrolled in (Student Id, Course Id)
4. Passed (Student Id, Course Id, Grade, Date)
5. Professor (Last Name, First Name, Type, Department Name)
6. Department (Name, Address)
7. Full Professor (Last Name, First Name, City of Birth)
8. City (Name, Region)
9. Foreign Student (Student Id, Country)
10. Chinese Student (Student Id, City of Birth)
11. Country (Name, Continent)
Phase 2 - Logical Design
Phase 2

7. Not so easy…. Phase 1 - Conceptual Design
Students of a University attend courses, and pass them. Courses have a last name, a first name and a year of enrollment. Students have an ID, a Last Name and First Name. For Chinese Students we want to represent City of Birth and Region of Birth. For Foreign Students we want to represent the Country of Birth and the Continent of Birth. A Course passed by a Student has a grade and a date. Courses are taught by professors. Professors have a last name and a first name. They may be Associate Professors or Full professors, only for Full Professors we are interested to the City of Birth, with name and region. Every professor belongs to a Department. Departments have a Name and an address.
Not so easy….
Phase 1 - Conceptual Design
First Name
Last Name
Born in
one
many ID
Teach
Name
Region
Associate
Professor
Full Professor
Belongs to
Address
Year of Enrollment
Passed
Enrolled in
Grade
Date
Chinese St.
Foreign St.
Born
Continent
Department
Country
Student
City
Course

8. Second strategy: proceed step by step (manage complexity)

9. Need for strategies in conceptual design
Teach
one
many
Associate
Professor
Full Professor
Related
Chinese St.
Foreign St.
Student
Course
Students of a University attend courses, and pass them. Courses have a last name, a first name and a year of enrollment. Students have an ID, a Last Name and First Name. For Chinese Students we want to represent City of Birth and Region of Birth. For Foreign Students we want to represent the Country of Birth and the Continent of Birth. A Course passed by a Student has a grade and a date. Courses are taught by professors. Professors have a last name and a first name. They may be Associate Professors or Full professors, only for Full Professors we are interested to the City of Birth, with name and region. Every professor belongs to a Department. Departments have a Name and an address.
Step 1
Step 2
First Name
Last Name
Born in
one
many ID
Teach
Name
Region
Associate
Professor
Full Professor
Belongs to
Address
Year of Enrollment
Passed
Enrolled in
Grade
Date
Chinese St.
Foreign St.
Born
Continent
Department
Country
Student
City
Course
Teach
one
many
Associate
Professor
Full Professor
Related
Chinese St.
Foreign St.
Student
Course

10. The issue of schema quality

11. Different schemas for the same requirements….
Students of a University attend courses, and pass them. Courses have a last name, a first name and a year of enrollment. Students have an ID, a Last Name and First Name. For Chinese Students we want to represent City of Birth and Region of Birth. For Foreign Students we want to represent the Country of Birth and the Continent of Birth. A Course passed by a Student has a grade and a date. Courses are taught by professors. Professors have a last name and a first name. They may be Associate Professors or Full professors, only for Full Professors we are interested to the City of Birth, with name and region. Every professor belongs to a Department. Departments have a Name and an address.
First Name
Last Name
Born in
one
many ID
Teach
Name
Region
Associate
Professor
Full Professor
Belongs to
Address
Year of Enrollment
Passed
Enrolled in
Grade
Date
Chinese St.
Foreign St.
Born
Continent
Department
Country
Student
City
Course
Schema 2
Student ID
Last Name
First Name
Country of Birth
Continent of Birth
City of Birth
Course Id
Course Name ……
…….
Student
Schema 1

12. The same in the relational model
Students of a University attend courses, and pass them. Courses have a last name, a first name and a year of enrollment. Students have an ID, a Last Name and First Name. For Chinese Students we want to represent City of Birth and Region of Birth. For Foreign Students we want to represent the Country of Birth and the Continent of Birth. A Course passed by a Student has a grade and a date. Courses are taught by professors. Professors have a last name and a first name. They may be Associate Professors or Full professors, only for Full Professors we are interested to the City of Birth, with name and region. Every professor belongs to a Department. Departments have a Name and an address.
1. Student (Student Id, Last Name, First Name, Type)
2. Course (Course Id, Year of Enrollment)
3. Enrolled in (Student Id, Course Id)
4. Passed (Student Id, Course Id, Grade, Date)
5. Professor (Last Name, First Name, Type, Department Name)
6. Department (Name, Address)
7. Full Professor (Last Name, First Name, City of Birth)
8. City (Name, Region)
9. Foreign Student (Student Id, Country)
10. Chinese Student (Student Id, City of Birth)
11. Country (Name, Continent)
Schema 2
1. Student (Student Id, Last Name, First Name, Type, Enrolled Course Id, Year of Enrollment, Passed course Id, Grade, Date, Professor Last Name, Professor First Name, Professor Type, Department Name, Department Address, Professor City of Birth, Region, Foreign Student Country of Birth, Foreign Student Continent, Chinese Student City of Birth, Chinese Student Region of Birth)
Schema 1

13. Motivating example: find “errors” in schemas
Students of a University attend courses, and pass them. Courses have a last name, a first name and a year of enrollment. Students have an ID, a Last Name and First Name. For Chinese Students we want to represent City of Birth and Region of Birth. For Foreign Students we want to represent the Country of Birth and the Continent of Birth. A Course passed by a Student has a grade and a date. Courses are taught by professors. Professors have a last name and a first name. They may be Associate Professors or Full professors, only for Full Professors we are interested to the City of Birth, with name and region. Every professor belongs to a Department. Departments have a Name and an address. ? ?
Schema 2
Schema 1
Last Name
Last Name ID
First Name
Name
Year of Enrollment ID
Name
Year of Enrollment
many
many
one
many
Student
Enrolled in
Course
Student
Enrolled in
Course
many
many
one
many
Passed
Passed
Teach
one
Teach
City of Birth
one
Country
Grade
Date
Foreign St.
Chinese St.
Grade
Date
Address
Name
many
First Name
many
Born
many
one
one
First Name
Born
many
one
Professor
many
one
Professor
many
Department
Belongs to
Located at
Department
Belongs to
Last Name
one
one
Last Name
Country
Name
Name
Scientific
Area
Full Professor
Associate
Professor
Name
Continent
Address
Name
Name
many
one
many
Region
City
Born in
Region
City
Born in
many

14. Contents Qualities of a conceptual schema
Strategies for conceptual design

15. Schema Quality Dimensions
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

16. Correctness with respect to the model
Concerns the correct use of the
categories of the model in representing
requirements.
Example – In the Entity Relationship
model we may represent the
logical link between persons and their
first names using the two entities Person
and FirstName and a relationship between
them. The schema is not correct wrt the
model since an entity should be used only
when the concept has a unique existence
in the real world and has an identifier.
Student
(1,n)
has
(1,1)
First Name
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

17. Correctness with respect to requirements
Concerns the correct representation of
the requirements in terms of the model
categories.
Example - In an organization each
department is headed by exactly one
manager and each manager may head
exactly one department.
If we represent Manager and Department
as entities, the Relationship between them
should be one-to-one; in this case, the
Schema is correct wrt requirements. If we
Use a one-to-many relationship, the
schema is incorrect.
Manager
(1,n)
heads
(1,1)
Department
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

18. Minimality/Redundancy
A schema is minimal if every
part of the requirements is
represented only once in the
schema.
In other words, it is
not possible to eliminate some
element from the schema
without compromising the
information content.
Student
1,n
Attends
1,n
Course
Assigned to
1,?
Teaches
1,n
Instructor
1,n
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

19. @C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008
Completeness
Measures the extent to which a
conceptual schema includes all the
conceptual elements necessary to
meet specified requirements.
It is possible that the designer has
not included certain characteristics
present in the requirements in the
schema, e.g., attributes related to
an entity Person; in this case, the
schema is incomplete.
Students have a code, a name, a place of birth.
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

20. @C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008
Completeness
Measures the extent to which a
conceptual schema includes all the
conceptual elements necessary to
meet specified requirements.
It is possible that the designer has
not included certain characteristics
present in the requirements in the
schema, e.g., attributes related to
an entity Person; in this case, the
schema is incomplete.
Students have a code, a name, a place of birth.
Student Id
Student
Student Name
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

21. @C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008
Pertinence
Measures how many
unnecessary conceptual
elements are included in the
conceptual schema.
In the case
of a schema that is not
pertinent, the designer has
Gone too far in modeling the
requirements, and has included
too many concepts.
Students have a code and a name.
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

22. Pertinence Measures how many unnecessary conceptual
Students have a code and a name.
Student Id
Student Name
Student
Place of Birth
Measures how many
unnecessary conceptual
elements are included in the
conceptual schema.
In the case
of a schema that is not
pertinent, the designer has
Gone too far in modeling the
requirements, and has included
too many concepts.

23. How to check and achieve Completeness and Pertinence

24. Exercise 4.1 - Completeness
Students have Student Id, Given Name, Surname, Date of Birth, City of Birth, Country of Birth. Courses have Course Id, Name, Year of Enrollment, Number of hours. Student pass Exams, with Grade and Date.
Name
Student
Student ID
City
Given Name
Country
born
many
one
Surname
many
Exam
Grade
many
Course
Course ID
Course Name
Year of Enrollment
Number of hours

25. Exercise 4.1 - Completeness
Students have Student Id, Given Name, Surname, Date of Birth, City of Birth, Country of Birth. Courses have Course Id, Name, Year of Enrollment, Number of hours. Student pass Exams, with Grade and Date.
Name
Student
Student ID
City
Country
born
Given Name
many
one
Surname
many
Exam
Grade
many
Course
Course ID
Course Name
Year of Enrollment
Number of hours

26. Exercise 4.1 - Completeness
Students have Student Id, Given Name, Surname, Date of Birth, City of Birth, Country of Birth. Courses have Course Id, Name, Year of Enrollment, Number of hours. Student pass Exams, with Grade and Date.
Name
Student
Student ID
City
Country
born
Given Name
many
one
Surname
many
Exam
Grade
many
Course
Course ID
Course Name
Year of Enrollment
Number of hours

27. Exercise 4.1 - Completeness
Students have Student Id, Given Name, Surname, Date of Birth, City of Birth, Country of Birth. Courses have Course Id, Name, Year of Enrollment, Number of hours. Student pass Exams, with Grade and Date.
Name
Student
Student ID
City
Country
born
Given Name
many
one
Surname
many
Exam
Grade
many
Course
Course ID
Course Name
Year of Enrollment
Number of hours

28. Exercise 4.1 - Completeness
Students have Student Id, Given Name, Surname, Date of Birth, City of Birth, Country of Birth. Courses have Course Id, Name, Year of Enrollment, Number of hours. Student pass Exams, with Grade and Date.
Name
Student
Student ID
City
Country
born
Given Name
many
one
Surname
many
Exam
Grade
The schema is lacking:
- Date of Birth of Students
- Date of Exams
many
Course
Course ID
Course Name
Year of Enrollment
Number of hours

29. Exercise 4.2 – Pertinence – Do yourself
Students have Student Id, Given Name, Surname, Date of Birth, City of Birth, Country of Birth. Courses have Course Id, Name, Year of Enrollment. Student pass Exams, with grade.
Name
Student
Student ID
City
Given Name
Country
born
many
one
Surname
many
Exam
Grade
many
Course
Course ID
Course Name
Year of Enrollment
Number of hours

30. Readability Intuitively, a schema is readable whenever it represents
the meaning of the reality represented by the schema in a
clear way for its intended use.
This simple, qualitative definition is not easy to translate in
a more formal way, since the evaluation expressed by the
word clearly conveys some elements of subjectivity.
In models, such as the Entity Relationship model, that
provide a graphical representation of the schema,
readability concerns both the diagram and the schema
itself.

31. Unreadable schema Employee Department Floor Purchase Vendor WarehouseOf
Order
Worker
Engineer
City
Born
Warehouse
Warranty
Type In
Employee
Vendor
Acquires
Works
Head
Floor
Located
Department
Produces
Item
Manages

32. Diagrammatic Readability as embedding in a grid
Floor
Located
Manages
Department
Head
Employee
Born
City
Works
Produces
Vendor
Worker
Engineer
Item In
Warranty
Type
Warehouse
Order
Purchase
Acquires Of

33. A Readable schema

34. Diagrammatic readability
With regard to the diagrammatic representation, readability can be expressed objectively by a number of aesthetic criteria that human beings adopt in drawing diagrams:
crossings between lines should be minimized,
graphic symbols should be embedded in a grid,
lines should be made of horizontal or vertical segments,
The number of bends in lines should be minimized,
the total area of the diagram should be minimized, and, finally,
Parents in generalization hierarchies should be positioned at a higher level in the diagram in respect to children.
The children entities in the generalization hierarchy should be symmetrical with respect to the parent entity.

35. Our example Embedded in a grid No crossings in lines
All lines are horizontal or vertical
Childs in generalizations symmetric w.r.t. parent
Parent upon childs
Purchase Of
Order
Worker
Engineer
City
Born
Warehouse
Warranty
Type In
Employee
Vendor
Acquires
Works
Head
Floor
Located
Department
Produces
Item
Manages
Floor
Located
Manages
Depart
ment
Head
Employee
Born
City
Works
Produces
Vendor
Worker
Engineer
Item In
Type
Warehouse
Warranty
Acquires
Order Of
Purchase

36. A Readable schema Department Employee Item Order Purchase WorkerOf
Worker
Engineer
City
Born
Warranty
Type
Employee
Vendor
Acquires
Works
Head
Floor
Located
Department
Produces
Item
Warehouse In
Manages

37. @C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008
Compactness
The second issue addressed by readability is the
compactness of schema representation.
Among the different conceptual schemas that equivalently
represent a certain reality, we prefer the one or the ones
that are more compact, because compactness favors
readability.
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

38. Transformation that preserves information content
and enhances compactness
Employee
Vendor
Worker
Engineer
Born
Born
City
Born
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

39. Transformation the preserves information content
and enhances compactness
Worker
Engineer
City
Born
Employee
Vendor
@C.Batini, F. Cabitza, G. Pasi, R. Schettini, 2008

40. Normalization in the ER model
Employee-Project
Employee Id
Surname
Given Name
Project Id
% of time of Employee
in Project
Project Name

41. Normalization Employee Project Employee Id Surname Given Name
Assigned to
(1,n)
Employee Id
Surname
Given Name
Project Id
% of time of Employee
in Project
Project Name

42. Unnormalized ER schema
Normalization
Normalized ER schema
Employee-Project
Employee #
Salary
Project #
Budget
Role
Employee
Project
Assigned to
1,n
Unnormalized ER schema

43. Strategies in Conceptual Design

44. Bottom up
Start from attributes, then choose entities, then relationships, finally is a and generalization hierarchies

45. Inside out
Start from the most important entity, and assign attributes. Then move to adjacent entities, relationships and is-a and generalization hierachies, until all the schema is represented.

46. Top down
Start from one entity, then refine the entity into a more articulated schema, then for each concept of the schema apply further refinements until all the schema is produced.

47. Top down Final refinement Requirements in natural language Initial
Second
refinement
Requirements in
natural language
Initial
schema

48. We compare three strategies
Bottom up
Inside Out
Top down

49. Bottom up Course Student Foreign St. Chinese St. Country
We are in China. Students are of two types, Foreign Students and Chinese Students. For both of them we want
to represent ID, First Name and Last Name. Furthermore, for Foreign Students we want to represent the
Country where they are born with Name and Continent. Students are related to courses, Courses have Name and
Year of Enrollment. Students are enrolled in courses; furthermore they pass Course with Grade and Date.
Name
Year of
Enrollment
Enrolled in
many ID
Last Name
First Name
Country
Chinese St.
Foreign St.
Course
Student
Passed
many
Grade
Date ID
Last Name
First Name ID
Last Name
First Name
Born
many
one
Name
Continent

50. Inside Out Student Course Foreign St. Chinese St. Country
We are in China. Students are of two types, Foreign Students and Chinese Students. For both of them we want
to represent ID, First Name and Last Name. Furthermore, for Foreign Students we want to represent the
Country where they are born with Name and Continent. Students are related to courses, Courses have Name and
Year of Enrollment. Students are enrolled in courses; furthermore they pass Course with Grade and Date.
Name
Year of
Enrollment
Enrolled in
many ID
Last Name
First Name
Student
Course
Passed
many
Grade
Date
Chinese St.
Foreign St.
Born
many
one
Country
Name
Continent

51. Top down Student Career Student Career Course Student Course Student
Name
Year of
Enrollment
Course
Student
Career
Passed
Enrolled in
many
Student
Course
Student ID
Last Name
First Name
Chinese St.
Foreign St.
Student
Student
Course
Related
Grade
Date
Passed
many
one
Country
Foreign St.
Born
Name
Continent
Country
Name
Year of
Enrollment
Course
Foreign St.
many
one
Country
Born
Chinese St.
Foreign St.
Student
Student
Career
Course
Related
Related
Passed
Enrolled in
many
Student ID
Last Name
First Name
Grade
Date
Passed
Name
Continent
Country

52. Strategies compared Strategies / Pros and cons Pros Cons Bottom up
Intuitive and «easy»
Forces restructurings
Oil stain
Compromise between bottom up and top down
Some restructuring
Top down
Need for an holistic view – difficult to achieve
No restructuring

53. Lesson Exercise 4.2

54. Exercise 4.2
Study the following data requirements for a hospital database and produce a conceptual schema using these strategies:
The bottom up strategy
The inside out strategy
The top-down strategy
The hospital database stores data about patients, their admission and discharge from hospital’s departments, and their treatments. For each patient, we know the name, address, sex, social security number, and insurance code. For each department, we know the department’s name, its location, the name of the doctor who heads it, the number of beds available, and the number of beds occupied. Each patient goes through multiple treatments during hospitalization; for each treatment, we store its name, duration, and the possible reactions to it the patient may have.

55. Inside out Strategy

56. Patient schema – Inside Out Strategy
Name
Address
Sex
SSN
Insurance
Code
Location
Name
Name of head
# of beds available
# of beds occupied
Patient
Department
Passed
many
Admission
date
Discharge
receive
many
Duration
Name
Reactions (1,n)
Treatment

57. Patient schema – Bottom up Strategy
The hospital database stores data about patients, their admission and discharge from hospital’s departments, and their treatments. For each patient, we know the name, address, sex, social security number, and insurance code. For each department, we know the department’s name, its location, the name of the doctor who heads it, the number of beds available, and the number of beds occupied. Each patient goes through multiple treatments during hospitalization; for each treatment, we store its name, duration, and the possible reactions to it the patient may have.
Name
Address
Sex
SSN
Insurance Code
Name
Location
Name of head
# of beds available
# of beds occupied
Admission date
Discharge date
Name
Reactions (1,n)
Duration

58. Bottom up Strategy

59. Patient schema – Bottom up Strategy - 1
Name
Address
Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Admission
date
Discharge
Duration
Name
Reactions (1,n)

60. Patient schema – Bottom up Strategy - 2
Name
Address
Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Patient
Department
Admission
date
Discharge
Duration
Name
Reactions (1,n)
Treatment

61. Patient schema – Bottom up Strategy - 3
Admitted
many
Patient
Department
Treatment
Name
Address
Sex
SSN
Insurance
Code
Location
Name of head
# of beds available
# of beds occupied
Reactions (1,n)
Duration
Admission
date
Discharge
Receives

62. Patient – Inside Out - 1
Patient
Name
Address
Sex
SSN
Insurance
Code

63. Patient – Inside Out - 2 Patient Department Admitted Name Address Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Patient
Department
many
many
Admitted
Admission
date
Discharge

64. Patient – Inside Out - 3 Patient Department Treatment Admitted
Name
Address
Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Patient
Department
many
many
Admitted
Admission
date
Discharge
many
Receives
Duration
many
Name
Reactions (1,n)
Treatment

65. Patient schema – Top down Strategy

66. Patient schema – Top down Strategy
Therapies

67. Patient schema – Top down Strategy
Patient and
Treatments
Department
Admitted
many

68. Patient schema – Top down Strategy
Name
Address
Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Patient and
Treatments
Department
Admitted
many

69. Patient schema – Top down Strategy
Name
Address
Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Patient and
Treatments
Department
Admitted
many
Admission
date
Discharge

70. Patient schema – Top down Strategy
Name
Address
Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Patient
Department
Admitted
many
Admission
date
Discharge
Receives
many
Treatment

71. Patient schema – Top down Strategy
Name
Address
Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Patient
Department
Admitted
many
Admission
date
Discharge
Receives
many
Name
Reactions (1,n)
Treatment

72. Patient schema – Top down Strategy
Name
Address
Sex
SSN
Insurance
Code
Name
Location
Name of head
# of beds available
# of beds occupied
Patient
Department
Admitted
many
Admission
date
Discharge
Receives
many
Duration
Name
Reactions (1,n)
Treatment