1. University of Milano Bicocca Carlo Batini Course on Data Base Design
Part 5 – Logical Design

2. © Carlo Batini, 2015
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4. Low level conceptual map

5. Logical design as a black box
Conceptual schema
Queries
Transactions
Application load
Logical design
Logical model
Logical schema

6. Logical design in the relational model
Conceptual schema
Logical design
Relational schema
Query load
Relational model

7. Notation simplification

8. Diagrammatic notation for ER diagrams adopted so far
Student Id B
Course
Student
Name
Exam
(1,n)
Foreing
Chinese
Surname
Grade
Date
Course Id
Country

9. Simplified notation adopted in this chapter
Student Id
Surname
Identifier of Entity B
Course
Student
Course Id
Name
Exam
(1,n)
Foreing
Chinese
Grade
Date
Country
Attribute of Entity
Attributes of Relationship

10. Translation of entities and relationships into relational tables

11. How to translate generalizations?
Student Id
Surname B
Student
Foreing
Chinese
Country ?

12. Optimization design issues - Computer structure: CPU and memories
Student Id
Surname B
Student
Course
Course Id
Name
Exam
(1,n)
Grade
Student (Student Id, Surname)
Exam (Student Id, Course Id, Grade)
Course (Course Id, Name)
Central
Processing
Unit
Main
memory
Secondary Memory
Channels
10-8/10-9
seconds
10-2

13. An example of partitioning
Employee Id
Place of Birth
Date of Birth
Level
Salary
Taxes B
Employee
Employee Id
Level
Salary
Taxes B
Empl1
Empl2
Place of Birth
Date of Birth
splitted
(1,n)

14. Transformation for achieving efficiency
Student Id
Surname B
Student
Course
Course Id
Name
Exam
(1,n)
Grade
Student Id
Course Id
Surname
Grade B
Student
Course

15. An entity with two groups of attributes accessed separately by queries

16. The three steps of logical design
Conceptual schema in the ER model
Simplification
and optimization
Simplified and optimized conceptual schema in the ER model
Translation
Relational schema

17. An ER schema with redundancies
Student Id
Surname
# of Exams passed
(1,n)
(1,n)
Course Id
Name
Student B
Course
Exam
Grade
Date

18. An entity with two identifiers and the two possible choices as primary keys
Student Id
Social Security Number
Given Name
Last Name B
Student
Student (Student Id, Social Security Number,
Given Name, Last Name)

19. Simplification and optimization in Atzeni’s book and in this Part 5
Four steps
Course
Student Id
Surname
# of Exams passed B
Student
Course Id
Name
Exam
(1,n)
Grade
Date
1. Redundancy analysis
2. Removing generalizations
Simplification step
Optimization step
Merging
Partitioning
3. Partitoning and/or merging
of entities/relationships
4. In case of multiple identifiers,
choice of identifier to be translated
into the primary key

20. Restructuring of Generalizations example
IdA A1 A2 B A C C1 B1 D
A-D
(1,n) E
C-E B1

21. Relevant cases of generalization restructuringsB A C
ABC
Case 1
Case 2
Case 3

22. First case of restructuring
IdA A1 A2 B A C C1 B1 D
A-D
(1,n) E
C-E

23. First case of restructuring

24. Corresponding assignment of properties to new constructs in case 1
IdA A1 A2 B A C C1 B1 D
A-D
(1,n) E
C-E
Type
(0,n)
ABC B1

25. Case 2

26. Corresponding assignment of properties to new constructs in case 2
IdA A1 A2 B A C C1 B1 D
A-D
(1,n) E
C-E
(0,1)
(1,1)
A-B
A-C B1

27. Restructuring of Generalizations third case
IdA A1 A2
IdA A1 A2 B1 D
A-D
(1,n)
(1,n)
(1,n) B A B
A-D D D
A-D
(1,n)
(1,n)
(1,n)
IdA A1 A2 C1 C B C
C-E E B1 C1
C-E
(1,n) E B1

28. Third case of restructuring

29. The schema of the motivating example after the simplification step
Course
Course Id
Name
Exam
(1,n)
Grade
Date
Student Id
Surname B
Student
Foreing
Chinese
Country
Type

30. Entity partitioning B Course B Student Student- Exam-Course Student Id
Surname
Type
Country
(1,n)
(1,n)
Course Id
Name
Student B
Course
Exam
Grade
Date
Student Id
Surname
Course Id
Name
Type
Country
Grade
Date
Student-
Exam-Course B

31. The three cases of entity (and related relationship) merging
KE1
KE2 E3 E4 B
E12 E1
many E2
one or

32. Result of merging in the motivating example

33. Transaltion of Entity B Student
Student ID
Given Name
Surname
Place of Birth B
Student
Student (Student Id, Given Name, Surname, Place of Birth)

34. Applying the translation in the motivating example
Student Id
Surname
Course Id
Name
Type
Country
Grade
Date
Student-
Exam-Course B
Student-Exam-Course (Student Id, Course Id, Surname, Name, Type, Country, Grade, Date)

35. Example considered in the translation of many to many binary relationship

36. Translation of many to many relationships
Student Id
Given Name
Surname
Place of Birth B
Student
Course
Exam
(1,n)
Grade
Date
Course Id
Name
# of Hours
Student (Student Id, Given Name, Surname, Place of Birth)
Exam (Student Id, Course Id, Grade, Date)
Course (Course Id, Name, # of hours)

37. Translation of many to many relationships
Student Id
Given Name
Surname
Place of Birth B
Student
Course
Exam
(1,n)
Grade
Date
Course Id
Name
# of Hours
Student (Student Id, Given Name, Surname, Place of Birth)
Exam (Student Id, Course Id, Grade, Date)
Course (Course Id, Name, # of hours)

38. Do not forget referential integrity constraints…
Student Id
Given Name
Surname
Place of Birth B
Student
Course
Exam
(1,n)
Grade
Date
Course Id
Name
# of Hours
Student (Student Id, Given Name, Surname, Place of Birth)
Exam (Student Id, Course Id, Grade, Date)
Course (Course Id, Name, # of hours)

39. Translation of ternary relationships
IdA A1 A2 B A
A-B-C
(1,n) C
IdB B1
IdC C1 C2 C3
ABC1
ABC2
A (IdA, A1, A2)
B (IdB, B1, B2)
A-B-C (IdA, IdB, IdC, ABC1, ABC2)
C (IdC, ABC1, ABC2)

40. Example of many to many recursive relationship
Person Id
Given Name
Surname
Person B
(1,n)
(1,n)
Person A
Person B
Relative
Type of parental Relationship
Person (Person Id, Given Name, Surname)
Relative (Person IdA, Person IdB, Type of parental relationship)

41. Translation of one to many relationships
Student Id
Given Name
Surname
Place of Birth B
Student
Country
Born
(1,1)
(1,n)
Country Id
Name
Continent
Student (Student Id, Given Name, Surname, Place of Birth, Country)
Country (Country Id, Name, Continent)

42. Translation of entity with external identifier
Student Id B
Student
University
St-Un
(1,1)
(1,n)
Surname
Name
City
Student (Student Id, University, Surname)
University (Name, City)

43. (1,1) to (1,1) Relationships A B Solution 1 A (KA, A1, KB)
B (KB, B1, B2)
Solution 2
A (KA, A1)
B (KB, B1, B2, KA) A KA A1
A-B B
(1,1) KB B1 B2

44. Translation of (0,1) to (1,1) Relationships
Solution 1
A (KA, A1)
B (KB, B1, B2, KA) A KA A1
A-B B
(0,1)
(1,1) KB B1 B2
Solution 2
A (KA, A1, KB)
B (KB, B1, B2)

45. The two cases of translation in the case (0,1) to (1,1) and corresponding instancesB KA A1 KB
ka1
a11
null
ka2
a12
kb1
ka3
a13
ka4
a14
kb2
ka5
a15
kb3
ka6
a16
kb4 KB B1 B2
kb1
b11
b21
kb2
b12
b22
kb3
b13
b23
kb4
b14
b24
Solution 1
A (KA, A1, KB)
B (KB, B1, B2) A KA A1
A-B B
(0,1)
(1,1) KB B1 B2 A B KA A1
ka1
a11
ka2
a12
ka3
a13
ka4
a14
ka5
a15
ka6
a16 KB B1 B2 KA
kb1
b11
b21
ka2
kb2
b12
b22
ka4
kb3
b13
b23
ka5
kb4
b14
b24
ka6
Solution 2
A (KA, A1)
B (KB, B1, B2, KA)

46. The three solutions for the (0,1) and (0,1) caseKA A1
A-B B
(0,1) KB B1 B2
Solution1
A (KA, A1)
B (KB, B1, B2, KA)
Solution 2
A (KA, A1, KB)
Solution 3
B (KB, B1, B2)
A-B (KA, KB)

47. Exercise 5.1

48. Exercise 5.1: Output of simplification and optimization
RBG
(0,1) KB B1
(1,n)
(1,1) KA A1 B B
RAB A
(0,1)
(1,n) G KG G1
RAGL
(1,n) H
(1,n) C1 C2 D1 D2 E E1 E2 L KL L1 C D
RCD
(0,n)
(0,n)

49. Exercise 5.1: Output of simplification and optimizationB A C D KB B1 D1 D2 E1 E2 KA A1
RBG
RAB
RAGL L G E
RCD KG G1 KL L1
(0,n) H
(1,1)
(0,1)
(1,n)

50. Exercise 5.1: Output of simplification and optimizationB A
BCDE KB B1 C1 C2 D1 D2 E1 E2
TYPE KA A1
RBG
RAB
RAGL L G KL L1
(0,n) H
(1,1)
(0,1)
(1,n)
RCD

51. Exercise 5.1: Steps of translationB A
BCDE KB B1 C1 C2 D1 D2 E1 E2
TYPE KA A1
RBG
RAB
RAGL L G KG G1 KL L1
(0,n) H
(1,1)
(0,1)
(1,n)
RCD
Legenda
many to many relationships
one to many relationships
one to one relationships
entities

52. Exercise 5.1: Output of transation
RBCDE (KB, B1, C1, C2, D1, D2, E1, E2, TYPE) RA (KA, A1) RG (KG, G1) RL (KL, L1) RCD (KBC, KBD) RBG (KB, KG) RAGL (KA, KG, KL, H)

53. Exercise 5.1: Adding referential integrity constraints
RBCDE (KB, B1, C1, C2, D1, D2, E1, E2, TYPE) RA (KA, A1) RG (KG, G1) RL (KL, L1) RCD (KBC, KBD) RBG (KB, KG) RAGL (KA, KG, KL, H)

54. Exercise 5.1: Adding referential integrity constraints
RBCDE (KB, B1, C1, C2, D1, D2, E1, E2, TYPE) RA (KA, A1, KB) RG (KG, G1) RL (KL, L1) RCD (KBC, KBD) RBG (KB, KG) RAGL (KA, KG, KL, H)

55. Exercise 5.2

56. Exercise 5.2 A B D C E F G B1 KA A1 E1 EF1 KD D1 RAB (0,1) REF (1,n)KG G1 G2 G3 G4 G5
RFG F1

57. Exercise 5.2: Output of simplificationB
DEF KA A1 B1 KD D1 E1 F1
RBD
(0,1)
(0,n)
REF
EF1 C1 C
RCD E F G KG G1 G2 G3 G4 G5
(1,n)
RFG

58. Exercise 5.2: Output of optimizationB
DEF KA A1 B1 KD D1 E1 F1
RBD
(0,1)
(0,n)
REF
EF1 C1 C G1
KG1
G11
G21
RFG1
(1,n)
RCD E G2
RFG2
KG2 G3 G4 G5 F
G12
(1,1)

59. Exercise 5.1: Output of transation
B (KA, A1, B1, KD) C (KA, A1, B1, KD) DEF (KD, D1, E1, F1, KG1, KG2) G1 ( KG1, G11, G21, KG2) G2 (KG2, G3, G4, G5) REF (KD1, KD2, EF1)

60. Exercise 5.2: Adding referential integrity constraints
B (KA, A1, B1, KD)
C (KA, A1, B1, KD)
DEF (KD, D1, E1, F1, KG1,KG2)
G1 ( KG1, G1, G2, KG2)
G2 (KG2, G3, G4, G5)
REF (KD1, KD2, EF1)

61. University Database Example

62. Exercise 5.3 Course Student Foreign St. Chinese St. Department CountryID
Last Name
First Name
Name
Year of Enrollment
Passed
Enrolled in
Course
(1,n)
(0,n)
Student
Grade
Date
(1,1)
Teach
Foreign St.
Chinese St.
Professor
First
Name
Last
(1,n)
Born
Country
Name
Continent
(1,n)
(1,1)
Born
(1,n)
(1,1)
Department
(1,1)
(1,n)
Belongs to
Associate
Professor
Full Professor
Name
Address
Name
Region
City
Born in
(1,1)
(1,n)

63. Exercise 5.3 - Output of Simplification and Optimization
First
Name
Last
City
Born in
(1,1) ID
Teach
Region
Full Professor
Department
many
Address
Year of Enrollment
Passed
Enrolled in
Course
(1,n)
(0,n)
Grade
Date
Born
Country
Continent
Student
(0,1)
Works in
Associate
Professor
Type

64. Exercise 5.3 - Output of Simplification and Optimization
Student
Student
Foreign St.
Chinese St.
Professor
Full Professor
Associate
Professor
Full Professor
Associate
Professor

65. Exercise 5.3 - Output of Translation
Student (Student Id, Last Name, First Name, Type, City, Country)
Course (Course Id, Year of Enrollment)
Enrolled in (Student Id, Course Id)
Passed (Student Id, Course Id, Grade, Date)
Full Professor (Last Name, First Name, Department Name, City)
Associate Professor (Last Name, First Name, Department Name)
Department (Name, Address)
City (Name, Region)
Foreign Student (Student Id, Country)
Chinese Student (Student Id, City of Birth)
Country (Name, Continent)

66. Exercise 5.3 - Adding referential integrity constraints
Student (Student Id, Last Name, First Name, Type, City, Country)
Course (Course Id, Year of Enrollment)
Enrolled in (Student Id, Course Id)
Passed (Student Id, Course Id, Grade, Date)
Full Professor (Last Name, First Name, Department Name, City)
Department (Name, Address)
Associate Professor (Last Name, First Name, Department Name)
City (Name, Region)
Foreign Student (Student Id, Country)
Chinese Student (Student Id, City of Birth)
Country (Name, Continent)

67. Concepts introduced in Part 5
Part 5 - Logical Design
Phase of Logical Design
Simplification and Optimization
Translation
Simplification Phase
Removing Generalizations
Optimization Phase
Partitoning of Entities/Relationships
Merging of Entities/Relationships
Translation Step
(Translation of an) Entity
Many to Many Relationship
One to Many Relationship
Ternary Relationship
Recursive Relationship
(1,1) to (1,1) Relationship
(0,1) to (1,1) Relationship
(0,1) to (0,1) Relationship

68. Resti

69. Normalization B City B City Country Student Student Student Id
born
(1,1)
(1,n)
Last Name
City
Name
Country
Continent
Student Id B
Student
born
(1,1)
Last Name
City
(1,n)
Name in
Country
Continent

70. Motivating Example B Course B Student Student Foreing Chinese Foreing
Course Id
Name
Exam
(1,n)
Grade
Date
Student Id
Surname B
Student
Foreing
Chinese
Country
Student Id
Surname B
Student
Foreing
Chinese
Country

71. Corresponding assignment of properties to new constructs in case 3

72. Restructuring generalizations in the motivating example

73. Translation of ER modeling constructs
Student Id
Surname B
Student
Course
Course Id
Name
Exam
(1,n)
Grade
Student Id
Surname
Student Id
Course Id
Grade
Course Id
Name
Student Id
Surname B
Student
Foreing
Chinese
Country ?

74. Choice among multiple identifiers
Employee Id
Place of Birth
Date of Birth
Level
Salary
Taxes B
Employee

75. Simplification and optimization step
Four steps
Course
Student Id
Surname
# of Exams passed B
Student
Course Id
Name
Exam
(1,n)
Grade
Date
1. Redundancy analysis
2. Removing generalizations
Simplification step
Optimization step
Merging
Partitioning
3. Partitioning and/or merging
of entities/relationships
4. In case of multiple identifiers,
choice of identifier to be translated
into the primary key

76. Simplification and optimization step
Course
Student Id
Surname
# of Exams passed B
Student
Course Id
Name
Exam
(1,n)
Grade
Date
1. Redundancy analysis
2. Removing generalizations
Simplification step
3. Partitioning or merging
of entities
4. In case of multiple identifiers,
choice of identifier to be translated
into the primary key
Optimization step
Merging
Partitioning

77. Removing generalizations
Student Id
Surname
Student B ?
Chinese
Student
Foreing
Student
Country

78. Simplification

79. Optimization – entity partitioning
Employee Id
Level
Salary
Taxes B
Empl1
Empl2
Place of Birth
Date of Birth
Same as
(1,n)
Employee

80. (0,1) to (1,1) Relationships A B A B A B Solution 1 A (KA, A1)KB B1 B2 A B
Solution 1
A (KA, A1)
B (KB, B1, B2, KA) KA A1
ka1
a11
ka2
a12
ka3
a13
ka4
a14 KB B1 B2 KA
kb1
b11
b21
ka1
kb2
b12
b22
ka2
kb3
b13
b23
ka3
kb4
b14
b24
ka4 A B A KA A1
A-B B
(0,1)
(1,1) KB B1 B2
Solution 2
A (KA, A1, KB)
B (KB, B1, B2) KA A1 KB
ka1
a11
null
ka2
a12
kb1
ka3
a13
ka4
a14
kb2 KB B1 B2
kb1
b11
b21
kb2
b12
b22
kb3
b13
b23
kb4
b14
b24