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Database Design

eXercise #4


Further Constraints

  1. Referring to the following predicates:
    key patterns 1
    Indicate those DEFINITELY UNSPLITTABLE, PROBABLY UNSPLITTABLE and DEFINITELY SPLITTABLE.

  2. Referring to the following predicates:
    key patterns 2
    Re-draw those predicates that are incorrectly formed.

  3. The following is an exerpt from a University results system - perform CSDP steps 1-5 on this data - be careful to identify derived information, and supply rules for derivation if possible on your schema.
    Subject	Year  Enrollment  Rating  NrStudents  %     Lecturer
    _______________________________________________________________
    CS121   1982  200         7       5           2.5   F.Bloggs
                              6      10           5
                              5      75          37.5
                              4      80          40
                              3      10           5
                              2       5           2.5
    
    CS123   1982  150         7       4           2.67  O.Paarts
                              6       8           5.33
                              5      60          40
                              4      70          46.67
                              1       6           4
    
    CS121   1983  250         7  .....
                              6  .....
                              5  .....
                              4  .....  <-- note that not all
                              3  .....      ratings are allocated
    CS007  etc.                             each year!
    


  4. This question involves the design of an information system for evaluating the cost of sending an air-mail parcel by Intemational Parcel Post.

    The table shown below is taken from Australia Post's booklet Postal Charges Easy Guide".

    International Parcel POST Charge per article
    Weight Category Zone 1 Zone 2 Zone 3 Zone 4 Zone 5
    Up to 1kg A 11.00 13.00 15.00 17.50 19.50
    1kg-2kg B 16.00 20.00 24.00 29.00 33.00
    2kg-3kg C 21.00 27.00 33.00 40.50 46.50
    3kg-4kg D 26.00 34.00 42.00 52.00 60.00
    4kg-5kg E 31.00 41.00 51.00 63.50 73.50
    5kg-6kg F 36.00 48.00 60.00 75.00 87.00
    6kg-7kg G 41.00 55.00 69.00 86.50 100.50
    7kg-8kg H 46.00 62.00 78.00 98.00 114.00
    8kg-9kg I 51.00 69.00 87.00 109.50 127.50
    9kg-1Okg J 56.00 76.00 96.00 121.00 141.00
    Each additional kg up to 20kg 5.00 7.00 9.00 11.50 13.50
    Maximum weight depends on country of destination

    While the more observant of you will already have noticed a definite pattem to the numbers in, this table, we will actually store these data because Australia Post may not always follow this rule in future.

    Note that, given a parcel's weight, we can determine the category to which it belongs because each category has a definite maximum and minimum weight. Further, given a parcel of a particular weight and a country of destination, we must be able to derive the appropriate postal charge.

    Countries to which a parcel may be sent are grouped into zones, e.g., the USA is in Zone 4 while the Solomon Islands are in Zone 1. No country can be in more than a single zone.

    Perform CSDP Steps 1-5 for this application. State any additional assumptions you have made in your solution. Where a fact type is derivable, provide a rule or computation scheme next to the schema.

  5. A fictitous company is organized into departments. Each department has a name, a number and an employee who manages that department. We keep track of the start date when that employee begins managing that department. A department may have several locations.

    A department controls a number of projects each of which has a number, name and single location.

    For each employee, we store their name, tax file number, address, salary, gender and date of birth. An employee is assigned to one department but may work on several projects within that department and may also work on projects not managed by their department. We keep track of the number of hours per week that an employee works on each project. We also keep track of the direct supervisor of each employee.

    We also keep track of the dependants of each employee for insurance purposes, with the name, gender, birth date and relation to the employee recorded for each dependant.

    Model this system, complete to STEP 5, being careful to annotate any assumptions you needed to make.

  6. A University keeps track of each student's name, student number, tax file number, current address, current phone number, permanent address and phone number, birth date, gender, year (1st, 2nd, ..., graduate), Major department, Minor Department (if any), and degree program (B.A, B.I.T, ..., Ph.D.). Some people accessing the system need to refer to the City, state, postcode and student's permanent address and to the student's first and last names. Both student number and tax file number uniquely identify the student.

    Each department is described by name, department code, office number, office phone number, and faculty. Both name and code have unique values for each department.

    Each course has a course name, short and verbose description, code number, contact hour count per semester, level and offering department. The code is unique for each course.

    Each course may be divided up into sections, each section has an instructor, semester, year and course and section number. The section number distinguishes different sections of the same course that are taught during the same semester/year; its values are 1, 2, 3... up to the number of sections taught inthat course.

    A grade reports has a student, section and grade.

    Model this system, complete to STEP 5, being careful to annotate any assumptions you needed to make.

  7. Referring to the following Conceptual Schema,
    Airport Conceptual Schema
    Place constraints on the schema to reflect your understanding of the 'real' world.

Solutions

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