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(1)(a) State(or underline) the appropriate attribute name(s) to identify the correct primary key for this relation, RaceEntryAndResult(RaceNumber, AthleteNumber, TimeSet). (b)Relations in a database should usually be fully normalised. Define what it means for a database to be fully normalised. (i) Produce an Entity-Relationship diagram showing the degree of the three relationships that exist between the entities.

(1)(a) State(or underline) the appropriate attribute name(s) to identify the correct primary key for this relation, RaceEntryAndResult(RaceNumber, AthleteNumber, TimeSet). (b)Relations in a database should usually be fully normalised. Define what it means for a database to be fully normalised. (i) Produce an Entity-Relationship diagram showing the degree of the three relationships that exist between the entities.

Computer Networking: A Top-Down Approach (7th Edition)
Computer Networking: A Top-Down Approach (7th Edition)
7th Edition
ISBN:9780133594140
Author:James Kurose, Keith Ross
Publisher:James Kurose, Keith Ross
Chapter1: Computer Networks And The Internet
Section: Chapter Questions
Problem R1RQ: What is the difference between a host and an end system? List several different types of end...
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(1)(a) State(or underline) the appropriate attribute name(s) to identify the correct primary key for this relation, RaceEntryAndResult(RaceNumber, AthleteNumber, TimeSet). (b)Relations in a database should usually be fully normalised. Define what it means for a database to be fully nomalised. (ii) Produce an Entity-Relationship diagram showing the degree of the three relationships that exist between the entities. (iii)(a) Athlete number 72 is to be entered into race number 9. Write the SQL commands that are required to make this entry. (b) Define Referential Integrity, and state one advantage of it. (c) The database system is to be extended for use in an inter-school athletics league. Users at any school in the country will be able to access the system to input the results of races. For this reason, two users might try to access or update the system at the same time. Explain the conditions under which simultaneous access to a database could cause a problem, and how this could be dealt with.
Transcribed Image Text:(1)(a) State(or underline) the appropriate attribute name(s) to identify the correct primary key for this relation, RaceEntryAndResult(RaceNumber, AthleteNumber, TimeSet). (b)Relations in a database should usually be fully normalised. Define what it means for a database to be fully nomalised. (ii) Produce an Entity-Relationship diagram showing the degree of the three relationships that exist between the entities. (iii)(a) Athlete number 72 is to be entered into race number 9. Write the SQL commands that are required to make this entry. (b) Define Referential Integrity, and state one advantage of it. (c) The database system is to be extended for use in an inter-school athletics league. Users at any school in the country will be able to access the system to input the results of races. For this reason, two users might try to access or update the system at the same time. Explain the conditions under which simultaneous access to a database could cause a problem, and how this could be dealt with.
7.A school stores information about its sports day in a relational database. The details of the track events are stored using the three relations presented below. Athlete (AthleteNumber, Forename, Surname, Class, Gender, DateOfBirth) Race (RaceNumber, Gender, Distance, Type, StartTime) RaceEntryAndRest:lt (RaceNun ber, AthieteNumber, TimeSet) Each athlete who takes part in a race is given a unique AthleteNumber. Athletes can run in more than one race. If they do, they keep the same AthleteNumber for the entire day. Many races are run throughout the day. An example race would be the boys 80m, high jump, the third race of the day, which starts at 13:30. The entry in the Race table for this race is shown in table below. RaceNumber 3. Gender Вoys Distance Туре 100m StartTime 13:30 08 Table 1 When an athlete is entered into a race, a record of the entry is created in the RaceEntryAndResult tuble. Initially, the TimeSet is recorded as 00:00.00 (meaning 0 minutes, 0 seconds, 0 hundredths of a second) to indicate that the race has not yet been run. After the race has been run, if the athlete successfully completes it, then their TimeSet value is updated to record the time that they achieved in minutes, seconds and hundreds of seconds. The TimeSet value remains at 00:00.00 for athletes who fail to complete the race. The primary keys in the Athlete and Race relations have been identified by underlining them. The correct primary key for the RaceEntryAndResult relation has not been identified.
Transcribed Image Text:7.A school stores information about its sports day in a relational database. The details of the track events are stored using the three relations presented below. Athlete (AthleteNumber, Forename, Surname, Class, Gender, DateOfBirth) Race (RaceNumber, Gender, Distance, Type, StartTime) RaceEntryAndRest:lt (RaceNun ber, AthieteNumber, TimeSet) Each athlete who takes part in a race is given a unique AthleteNumber. Athletes can run in more than one race. If they do, they keep the same AthleteNumber for the entire day. Many races are run throughout the day. An example race would be the boys 80m, high jump, the third race of the day, which starts at 13:30. The entry in the Race table for this race is shown in table below. RaceNumber 3. Gender Вoys Distance Туре 100m StartTime 13:30 08 Table 1 When an athlete is entered into a race, a record of the entry is created in the RaceEntryAndResult tuble. Initially, the TimeSet is recorded as 00:00.00 (meaning 0 minutes, 0 seconds, 0 hundredths of a second) to indicate that the race has not yet been run. After the race has been run, if the athlete successfully completes it, then their TimeSet value is updated to record the time that they achieved in minutes, seconds and hundreds of seconds. The TimeSet value remains at 00:00.00 for athletes who fail to complete the race. The primary keys in the Athlete and Race relations have been identified by underlining them. The correct primary key for the RaceEntryAndResult relation has not been identified.
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