caubert / CSCI_3410 (public) (License: CC BY 4.0) (since 2018-05-16) (hash sha1)
Material for Database Class.
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List of commits:
Subject Hash Author Date (UTC)
Fixing some exercises. d5053a4b04b16b1817f2e8edb67f9ca7a6c48eb9 au 2018-12-21 01:24:09
Started to externalize the code, fixed the makefile, added a style for HTML files, fixed a lot of solution / problem / exercise environment, cleaned some fig code cfc0c26c5fb9ea64dfd101b9a1a70bc34dfa7082 au 2018-12-20 07:19:10
Re-organization of the structure and of the makefile. d352a7419a507c83374d78c8723d3aaebbaf1e0d au 2018-12-19 02:36:38
Pushing to merge. 92a45b2d1f200221602d730030f87f26e65e335d au 2018-12-19 01:13:42
Pushing to merge. d937aa46e12ee344113794dbb778eccb727819d3 au 2018-12-19 01:09:15
Fixing underline + solution environment. 4f207ab8ae51b1d87d0e83b7b813a91e30bf361f aubert@math.cnrs.fr 2018-12-18 20:03:10
Fixing underline + solution environment. 895823a4d392501285e613325078e9fce7bdd95b aubert@math.cnrs.fr 2018-12-18 20:02:55
Adding info. relative to website aee6744e0c80c31fdf3de459a3265db2211c8b9f aubert@math.cnrs.fr 2018-12-18 14:24:50
Finishing to externalize figures to external files. b7b49588bde465058c526454b938ac27b1447487 aubert@math.cnrs.fr 2018-12-17 20:01:54
Factorizing some aspect, separating fugires, re-wrote makefil, added treatment for html and odt outputs. 91d14fa349fe376408bcc48e4ada948777bda5a0 au 2018-12-17 02:57:14
Fixing project archeticture, tayloring README and moving typesetting section from lecture notes to README. c00c920db70a59ee8626134287aa47455fcb3e03 au 2018-12-16 19:51:52
Fine-tuning makefile 2ce6e9dea5235a97c02b97e548567ff4584c3153 au 2018-12-16 05:41:35
Fixing da441e5483d8153bff9b25f50230f584c4d67c5e au 2018-12-16 05:38:00
re-adding templates. bfe4f6aa774c7befef9eda07f31edb5c9907cedb au 2018-12-16 05:30:19
Restore er tex files. 771634fed59ac3a00fa3fa8ee292e98c4e35e3d6 au 2018-12-16 05:26:43
Changing vect. format from SVG to PDF. fa1276c21b6d139d52bd2c0405a9eb694e1a932d au 2018-12-16 05:25:50
Fixing minor typos 3fd56098f9022b48fadff8e3ea10fd7fcd49213a au 2018-12-16 04:05:47
Re-organization of the project. ccb3e4e35a17076f72b836720948ba7cfe86155b au 2018-12-16 03:16:19
Ending reporting notes on paper, added planned schedule, added meta-info and made tthe pdf TOC deeper. 96ffdff901b7e059471c34d7f7df6771ded38783 aubert@math.cnrs.fr 2018-05-30 15:46:13
Starting to work on ER def, adding some diagrams. 4a938b9a338846c988800a1cc4d0c5f9fcd31f8d aubert@math.cnrs.fr 2018-05-29 21:16:02
Commit d5053a4b04b16b1817f2e8edb67f9ca7a6c48eb9 - Fixing some exercises.
Author: au
Author date (UTC): 2018-12-21 01:24
Committer name: au
Committer date (UTC): 2018-12-21 01:24
Parent(s): cfc0c26c5fb9ea64dfd101b9a1a70bc34dfa7082
Signer:
Signing key:
Signing status: N
Tree: b8eff28d18e25564452044f655c5684e7f9b2b7e
File Lines added Lines deleted
notes/lectures_notes.md 108 75
File notes/lectures_notes.md changed (mode: 100644) (index 21b45fe..5b31f3e)
... ... U | T | U | U
1545 1545
1546 1546 || ||
1547 1547 :--: | :--: :--: | :--:
1548 **NOT** | ~
1548 **NOT** | \
1549 1549 T | F T | F
1550 1550 F | T F | T
1551 1551 U | U U | U
 
... ... At the logical (conceptual) and physical (implementation) levels.
3553 3553
3554 3554 Goals: Goals:
3555 3555
3556 a. Information preservation
3557 b. Minimum redundancy
3558 c. Make queries easy
3556 #. Information preservation (and avoid loss of information)
3557 #. Minimum redundancy
3558 #. Make queries easy (avoid redundant work, make `select` / `join` easy)
3559 3559
3560 3560 ### General rules ### General rules
3561 3561
 
... ... c. Make queries easy
3566 3566 #### No anomalies #### No anomalies
3567 3567
3568 3568 #. Insertion Anomalies #. Insertion Anomalies
3569
3570 Having to invent values or to put `NULL` to insert tuples, especially on a key attribute!
3569 : Having to invent values or to put `NULL` to insert tuples, especially on a key attribute!
3571 3570
3572 3571 #. Deletion Anomalies #. Deletion Anomalies
3573
3574 Loosing information inadvertently
3572 : Loosing information inadvertently
3575 3573
3576 3574 #. Modification Anomalies #. Modification Anomalies
3577
3578 Updated have to be consistent.
3575 : Updated have to be consistent.
3579 3576
3580 3577 (Bad!) Example: (Bad!) Example:
3581 3578
 
... ... Transform into "Emergency Contact in University" relation (bonus: allow multiple
3606 3603
3607 3604 Example with advisorOffice and Office: if we try to write a join to obtain the phone number of a student's advisor, we will obtain all the phone. (Not clear example, find a better one). Example with advisorOffice and Office: if we try to write a join to obtain the phone number of a student's advisor, we will obtain all the phone. (Not clear example, find a better one).
3608 3605
3609 ---
3610
3611 **Last time:**
3612
3613 Check: 1) Clear Semantics, 2) Absence of Anomalies, 3) Rarity of NULL, 4) Identical Attributes in Different Tables should have a FK / PK relation.
3614
3615 Goals: To avoid redundant work, loss of info., difficulties to select / join, redundancy.
3606 ### Example
3616 3607
3617 3608 ~~~ ~~~
3618 3609
 
... ... Corrected to:
3625 3616
3626 3617 ~~~ ~~~
3627 3618
3628 MARKER(Owner, Color, Brand)
3619 MARKER(Owner, Color, B͟r͟a͟n͟d͟)
3629 3620
3630 TEACHER(Office, Name, Phone)
3621 TEACHER(Office, N͟a͟m͟e͟, Phone)
3631 3622
3632 BRAND(Name, Email)
3623 BRAND(N͟a͟m͟e͟, Email)
3633 3624 ~~~ ~~~
3634 3625
3635 Brand, Name and Name being the ID.
3636 3626
3637 3627 ### Functional dependencies ### Functional dependencies
3638 3628
3639 Formal tool to assess how "good" a database is, a property of the relation schema.
3629 Functional dependencies (FD) is a formal tool used to assess how "good" a database is, a property of the relation schema.
3640 3630
3641 3631 #### Using semantics of attributes #### Using semantics of attributes
3642 3632
 
... ... Example of Use Case
3926 3916 ## Exercises {-} ## Exercises {-}
3927 3917
3928 3918 Exercise +.# Exercise +.#
3929 ~ What could be the decomposition of an attribute used to store an email address? When could that be useful?
3919
3920 : What could be the decomposition of an attribute used to store an email address? When could that be useful?
3930 3921
3931 3922 Exercise +.# Exercise +.#
3932 ~ Draw the ER diagram for a "COMPUTER" entity that has one multivalued attribute "Operating\_System", a composite attribute "Devices" (decomposed into "Keyboard" and "Mouse") and an "Id" key attribute.
3923
3924 : Draw the ER diagram for a "COMPUTER" entity that has one multivalued attribute "Operating\_System", a composite attribute "Devices" (decomposed into "Keyboard" and "Mouse") and an "Id" key attribute.
3933 3925
3934 3926 Exercise +.# Exercise +.#
3935 ~ Draw the ER diagram for a "CELLPHONE" entity that has a composite attribute "Plan" (decomposed into "Carrier" and "Price"), a "Mobile\_identification\_number" key attribute, and a multi-valued "App\_Installed" attribute.
3927
3928 : Draw the ER diagram for a "CELLPHONE" entity that has a composite attribute "Plan" (decomposed into "Carrier" and "Price"), a "Mobile\_identification\_number" key attribute, and a multi-valued "App\_Installed" attribute.
3936 3929
3937 3930 Exercise +.# Exercise +.#
3938 ~ Name one difference between a primary key in the relational model, and a key attribute in the ER model.
3931
3932 : Name one difference between a primary key in the relational model, and a key attribute in the ER model.
3939 3933
3940 3934 Exercise +.# Exercise +.#
3941 ~ What is the difference between an entity type and a weak entity type?
3935
3936 : What is the difference between an entity type and a weak entity type?
3942 3937
3943 3938 Exercise +.# Exercise +.#
3944 ~ What is the degree of a relationship type?
3939
3940 : What is the degree of a relationship type?
3945 3941
3946 3942 Exercise +.# Exercise +.#
3947 ~ What is a self-referencing, or recursive, relationship type? Give two examples.
3943
3944 : What is a self-referencing, or recursive, relationship type? Give two examples.
3948 3945
3949 3946 Exercise +.# Exercise +.#
3950 ~ What does it mean for a binary relationship type "Owner" between entity types "Person" and "Computer" to have a cardinality ration $M:N$?
3947
3948 : What does it mean for a binary relationship type "Owner" between entity types "Person" and "Computer" to have a cardinality ration $M:N$?
3951 3949
3952 3950 Exercise +.# Exercise +.#
3953 ~ What are the two possible structural constraints on a relationship type?
3951
3952 : What are the two possible structural constraints on a relationship type?
3954 3953
3955 3954 Exercise +.# Exercise +.#
3956 ~ Under what condition(s) can an attribute of a binary relationship type be migrated to become an attribute of one of the participating entity type?
3955
3956 : Under what condition(s) can an attribute of a binary relationship type be migrated to become an attribute of one of the participating entity type?
3957 3957
3958 3958 Exercise +.# Exercise +.#
3959 ~ What is a partial key?
3959
3960 : What is a partial key?
3960 3961
3961 3962 Exercise +.# Exercise +.#
3962 ~ For the following binary relationships, suggest cardinality ratios based on the common-sense meaning of the entity types.
3963 3963
3964 : For the following binary relationships, suggest cardinality ratios based on the common-sense meaning of the entity types.
3965
3966 <!-- Bug with table -->
3964 3967 Entity 1 | Cardinality Ratio | Entity 2 | Entity 1 | Cardinality Ratio | Entity 2 |
3965 3968 | --- | :---: | --- | | --- | :---: | --- |
3966 STUDENT | | MAJOR
3967 CAR | | TAG
3968 INSTRUCTOR | | LECTURE
3969 INSTRUCTOR | | OFFICE
3970 COMPUTER | | OPERATING\_SYSTEM
3969 STUDENT | \ | MAJOR
3970 CAR | \ | TAG
3971 INSTRUCTOR | \ | LECTURE
3972 INSTRUCTOR | \ | OFFICE
3973 COMPUTER | \ | OPERATING\_SYSTEM
3971 3974
3972 3975 Exercise +.# Exercise +.#
3973 ~ Give an example of a binary relationship type of cardinality $1:N$.
3976
3977 : Give an example of a binary relationship type of cardinality $1:N$.
3974 3978
3975 3979 Exercise +.# Exercise +.#
3976 ~ Give an example of a binary relationship type of cardinality $N:1$, and draw the corresponding diagram (you don't have to include details on the participating entity types).
3980
3981 : Give an example of a binary relationship type of cardinality $N:1$, and draw the corresponding diagram (you don't have to include details on the participating entity types).
3977 3982
3978 3983 Exercise +.# Exercise +.#
3979 ~ Draw an ER diagram with a single entity type, with two stored attributes and one derived attribute. In your answer, it should be clear that the value for the derived attribute will always be obtained from the value(s) for the other attribute(s).
3984
3985 : Draw an ER diagram with a single entity type, with two stored attributes and one derived attribute. In your answer, it should be clear that the value for the derived attribute will always be obtained from the value(s) for the other attribute(s).
3980 3986
3981 3987 Exercise +.# Exercise +.#
3982 ~ Draw an ER diagram expressing the total participation of an entity type "BURGER" in a binary relation "CONTAINS" between "BURGER" and "INGREDIENT".
3988
3989 : Draw an ER diagram expressing the total participation of an entity type "BURGER" in a binary relation "CONTAINS" between "BURGER" and "INGREDIENT".
3983 3990 What would be the ratio of such a relation? What would be the ratio of such a relation?
3984 3991
3985 3992 Exercise +.# Exercise +.#
3986 ~ Convert the following ER diagram into a relational model:
3993 ~
3994 Convert the following ER diagram into a relational model:
3987 3995
3988 ![](fig/er/Stays_At)
3989 \
3996 ![](fig/er/Stays_At)
3990 3997
3991 3998 Exercise +.# Exercise +.#
3992 ~ Why do weak entity type have a total participation constraint?
3999
4000 : Why do weak entity type have a total participation constraint?
3993 4001
3994 4002 Exercise +.# Exercise +.#
3995 ~ What is insertion anomaly? Give an example.
4003
4004 : What is insertion anomaly? Give an example.
3996 4005
3997 4006 Exercise +.# Exercise +.#
3998 ~ What is deletion anomaly? Is it a desirable feature?
4007
4008 : What is deletion anomaly? Is it a desirable feature?
3999 4009
4000 4010 Exercise +.# Exercise +.#
4001 ~ Why should we avoid attributes whose value will often be `NULL`? Can the usage of `NULL` be completely avoided?
4011
4012 : Why should we avoid attributes whose value will often be `NULL`? Can the usage of `NULL` be completely avoided?
4002 4013
4003 4014 Exercise +.# Exercise +.#
4004 ~ Consider the following relation:
4015 ~
4016
4017 Consider the following relation:
4005 4018
4006 4019 PROF(S͟S͟N͟, Name, Department, Bike\_brand) PROF(S͟S͟N͟, Name, Department, Bike\_brand)
4007 4020
 
... ... Exercise +.#
4009 4022 How should we store this information? How should we store this information?
4010 4023
4011 4024 Exercise +.# Exercise +.#
4012 ~ Consider the following relation:
4025 ~
4026 Consider the following relation:
4013 4027
4014 4028 STUDENT(S͟S͟N͟, Name, $…$, Sibling\_On\_Campus) STUDENT(S͟S͟N͟, Name, $…$, Sibling\_On\_Campus)
4015 4029
 
... ... Exercise +.#
4017 4031 How should we store this information? How should we store this information?
4018 4032
4019 4033 Exercise +.# Exercise +.#
4020 ~ Consider the following relational database schema:
4034 ~
4035 Consider the following relational database schema:
4021 4036
4022 4037 STUDENT(L͟o͟g͟i͟n͟, Name, $…$, Major, Major\_Head) STUDENT(L͟o͟g͟i͟n͟, Name, $…$, Major, Major\_Head)
4023 4038 DEPARTMENT(C͟o͟d͟e͟, Name, Major\_Head) DEPARTMENT(C͟o͟d͟e͟, Name, Major\_Head)
 
... ... Exercise +.#
4025 4040 Assuming that "Major" is a foreign key referencing "DEPARTMENT.Code", what is the problem with that schema? How could you address it? Assuming that "Major" is a foreign key referencing "DEPARTMENT.Code", what is the problem with that schema? How could you address it?
4026 4041
4027 4042 Exercise +.# Exercise +.#
4028 ~ Consider the relation $R(A , B, C, D, E, F)$ and the following functional dependencies:
4043 ~
4044 Consider the relation $R(A , B, C, D, E, F)$ and the following functional dependencies:
4029 4045
4030 4046 #. $F \to \{D, C\}, D \to \{B, E\}, \{B, E\} \to A$ #. $F \to \{D, C\}, D \to \{B, E\}, \{B, E\} \to A$
4031 4047 #. $\{A, B\} \to \{C, D\}, \{B, E\} \to F$ #. $\{A, B\} \to \{C, D\}, \{B, E\} \to F$
 
... ... Exercise +.#
4034 4050 For each set of functional dependency, give a key for $R$. We want a key, so it has to be minimal. For each set of functional dependency, give a key for $R$. We want a key, so it has to be minimal.
4035 4051
4036 4052 Exercise +.# Exercise +.#
4037 ~ Consider the relation $R(A, B, C, D, E, F)$ and the following functional dependencies:
4053 ~
4054 Consider the relation $R(A, B, C, D, E, F)$ and the following functional dependencies:
4038 4055 \[ A \to \{D, E\}, D \to \{B, F\}, \{B, E\} \to A, \{A,C\} \to \{B, D, F\}, A \to F\] \[ A \to \{D, E\}, D \to \{B, F\}, \{B, E\} \to A, \{A,C\} \to \{B, D, F\}, A \to F\]
4039 4056 Answer the following: Answer the following:
4040 4057
 
... ... Exercise +.#
4042 4059 #. How many transitive dependencies can you find? Give them and justify them. #. How many transitive dependencies can you find? Give them and justify them.
4043 4060
4044 4061 Exercise +.# Exercise +.#
4045 ~ Consider the relation $R(A, B, C, D)$ and answer the following:
4062 ~
4063 Consider the relation $R(A, B, C, D)$ and answer the following:
4046 4064
4047 4065 #. If $\{A, B\}$ is the only key, is $\{A, B\} \to \{C,D\}, \{B, C\} \to D$ a 2NF? List the nonprime attributes and justify. #. If $\{A, B\}$ is the only key, is $\{A, B\} \to \{C,D\}, \{B, C\} \to D$ a 2NF? List the nonprime attributes and justify.
4048 4066 #. If $\{A, B, C\}$ is the only key, is $A \to \{B, D\}, \{A, B, C\} \to D$ a 2NF? List the nonprime attributes and justify. #. If $\{A, B, C\}$ is the only key, is $A \to \{B, D\}, \{A, B, C\} \to D$ a 2NF? List the nonprime attributes and justify.
4049 4067
4050 4068 Exercise +.# Exercise +.#
4051 ~ Consider the relation $R(A, B, C, D, E, F)$ with candidate keys $\{A, B\}$ and $C$. Answer the following:
4069 ~
4070 Consider the relation $R(A, B, C, D, E, F)$ with candidate keys $\{A, B\}$ and $C$. Answer the following:
4052 4071
4053 4072 #. What are the prime attributes in $R$? #. What are the prime attributes in $R$?
4054 4073 #. Is $\{C,D\} \to E$ a fully functional dependency? #. Is $\{C,D\} \to E$ a fully functional dependency?
4055 4074 #. Write a set of functional dependencies containing at least one transitive depency, and justify your answer. #. Write a set of functional dependencies containing at least one transitive depency, and justify your answer.
4056 4075
4057 4076 Exercise +.# Exercise +.#
4058 ~ Consider the relation $R(A , B, C, D, E)$ and the following functional dependencies:
4077 ~
4078 Consider the relation $R(A , B, C, D, E)$ and the following functional dependencies:
4059 4079
4060 4080 #. $C \to D, \{C, B\} \to A, A \to \{B, C, D\}, B \to E$ #. $C \to D, \{C, B\} \to A, A \to \{B, C, D\}, B \to E$
4061 4081 #. $\ A \to \{C, D\}, C \to B, D \to E, \{E, C\} \to A$ #. $\ A \to \{C, D\}, C \to B, D \to E, \{E, C\} \to A$
 
... ... Exercise +.#
4064 4084 For each one, give one candidate key for $R$. For each one, give one candidate key for $R$.
4065 4085
4066 4086 Exercise +.# Exercise +.#
4067 ~ Consider the relation $R(A, B, C, D, E)$ and answer the following:
4087 ~
4088 Consider the relation $R(A, B, C, D, E)$ and answer the following:
4068 4089
4069 4090 #. If $\{A, B\}$ is the primary key, is $B \to E, C \to D$ a 2NF?% List the nonprime attributes and justify. #. If $\{A, B\}$ is the primary key, is $B \to E, C \to D$ a 2NF?% List the nonprime attributes and justify.
4070 4091 #. If $\{A\}$ is the primary key, is $B \to C, B \to D$ a 2NF?% List the nonprime attributes and justify. #. If $\{A\}$ is the primary key, is $B \to C, B \to D$ a 2NF?% List the nonprime attributes and justify.
4071 4092
4072 4093 Exercise +.# Exercise +.#
4073 ~ Consider the relation $R(A, B, C, D, E, F)$, and let $\{B, D\}$ be the primary key, and have additionnaly the functional dependencies $\{A, D\} \to E, C \to F$.
4094
4095 : Consider the relation $R(A, B, C, D, E, F)$, and let $\{B, D\}$ be the primary key, and have additionnaly the functional dependencies $\{A, D\} \to E, C \to F$.
4074 4096 This relation is not in 3NF, can you tell why? This relation is not in 3NF, can you tell why?
4075 4097
4076 4098 Exercise +.# Exercise +.#
4077 ~ Consider the relation $R(A, B, C, D)$ and answer the following:
4099 ~
4100 Consider the relation $R(A, B, C, D)$ and answer the following:
4078 4101
4079 4102 #. If $A$ is the only key, is $A \to \{B,C,D\}, \{A, B\} \to C, \{B, C\} \to D$ a 3NF? List the nonprime attributes and justify. #. If $A$ is the only key, is $A \to \{B,C,D\}, \{A, B\} \to C, \{B, C\} \to D$ a 3NF? List the nonprime attributes and justify.
4080 4103 #. If $B$ is the only key, is $B \to \{A, C, D\}, A \to \{C, D\}, \{A, C\} \to D$ a 3NF? List the nonprime attributes and justify. #. If $B$ is the only key, is $B \to \{A, C, D\}, A \to \{C, D\}, \{A, C\} \to D$ a 3NF? List the nonprime attributes and justify.
4081 4104
4082 4105 Exercise +.# Exercise +.#
4083 ~ Consider the relation $R(A, B, C, D, E)$ and the functional dependencies $ \{A, B\} \to C, B \to D, C \to E$. Answer the following:
4106 ~
4107 Consider the relation $R(A, B, C, D, E)$ and the functional dependencies $ \{A, B\} \to C, B \to D, C \to E$. Answer the following:
4084 4108
4085 4109 #. $A$ by itself is not a primary key, but what is the only key that contains $A$? #. $A$ by itself is not a primary key, but what is the only key that contains $A$?
4086 4110 #. List the non-prime attributes. #. List the non-prime attributes.
 
... ... Exercise +.#
4088 4112 #. One of the relation you obtained at the previous step is likely not to be in 3NF. Can you normalize it? If yes, how? #. One of the relation you obtained at the previous step is likely not to be in 3NF. Can you normalize it? If yes, how?
4089 4113
4090 4114 Exercise +.# Exercise +.#
4091 ~ What are the two different categories of U.M.L. diagram?
4115
4116 : What are the two different categories of U.M.L. diagram?
4092 4117
4093 4118 Exercise +.# Exercise +.#
4094 ~ Can a `C++` developer working on Linux and a `Java` developer working on MacOS use the same class diagram as a basis to write their programs?
4119
4120 : Can a `C++` developer working on Linux and a `Java` developer working on MacOS use the same class diagram as a basis to write their programs?
4095 4121 Justify your answer. Justify your answer.
4096 4122
4097 4123 Exercise +.# Exercise +.#
4098 ~ What kind of diagram should we use if we want to …
4124 ~
4125 What kind of diagram should we use if we want to …
4099 4126
4100 4127 #. describe the functional behavior of the system as seen by the user? #. describe the functional behavior of the system as seen by the user?
4101 4128 #. capture the flow of messages in a software? #. capture the flow of messages in a software?
4102 4129 #. represent the workflow of actions of an user? #. represent the workflow of actions of an user?
4103 4130
4104 4131 Exercise +.# Exercise +.#
4105 ~ Name two reasons why one would want to use a U.M.L. class diagram over an E.R. diagram to represent a conceptual schema.
4106 4132
4107 Exercise +.#
4108 ~ Consider the following diagram:
4133 : Name two reasons why one would want to use a U.M.L. class diagram over an E.R. diagram to represent a conceptual schema.
4109 4134
4110 ![](fig/uml/Flight)
4135 Exercise +.#
4136 ~
4137 Consider the following diagram:
4111 4138
4112 Give the number of attributes for both classes, and suggest two operations for the class that doesn't have any. Discuss the multiplicities: why did the designer picked those values?
4139 ![](fig/uml/Flight)
4140
4141 Give the number of attributes for both classes, and suggest two operations for the class that doesn't have any. Discuss the multiplicities: why did the designer picked those values?
4113 4142
4114 4143 Exercise +.# Exercise +.#
4115 ~ Briefly explain the difference between an aggregation and a composition association.
4144
4145 : Briefly explain the difference between an aggregation and a composition association.
4116 4146
4117 4147 Exercise +.# Exercise +.#
4118 ~ How is generalization (or inheritance) represented in a U.M.L. class diagram?
4148
4149 : How is generalization (or inheritance) represented in a U.M.L. class diagram?
4119 4150 Why is such a concept useful? Why is such a concept useful?
4120 4151
4121 4152 Exercise +.# Exercise +.#
4122 ~ Convert the following E.R. diagram into a U.M.L. class diagram:
4153 ~
4154
4155 Convert the following E.R. diagram into a U.M.L. class diagram:
4156
4157 ![](fig/er/Pilot)
4123 4158
4124 ![](fig/er/Pilot)
4125 \
4126 4159
4127 4160 ## Solution to Exercises {-} ## Solution to Exercises {-}
4128 4161
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git clone https://rocketgit.com/user/caubert/CSCI_3410

Clone this repository using ssh (do not forget to upload a key first):
git clone ssh://rocketgit@ssh.rocketgit.com/user/caubert/CSCI_3410

Clone this repository using git:
git clone git://git.rocketgit.com/user/caubert/CSCI_3410

You are allowed to anonymously push to this repository.
This means that your pushed commits will automatically be transformed into a merge request:
... clone the repository ...
... make some changes and some commits ...
git push origin main