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Worksheet Chapter 7 - Memo

Worksheets for practise with memos
Course

Introduction to Databases and Databases Management Systems:Part 1 (CSIQ2634)

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Academic year: 2021/2022
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University of the Free State

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UNIVERSITY OF THE FREE STATE

Department of Computer Science

and Informatics

CSIS

Worksheet (Chapter 7)

Question 1 1NF Step 1: Eliminate repeating groups: Supplier Supplier City Part Part Quantity Part Colour Sup1 Cape Town ABCB123 12 Grey Sup1 Cape Town JKU87 10 Yellow Sup1 Cape Town FDGE65 5 Blue Sup2 Johannesburg JKU87 3 Yellow Sup3 Cape Town ABCB123 4 Grey Sup3 Cape Town GHSD789 2 Grey

Step 2: Identify the primary key Supplier, Part Step 3: Identify all dependencies

Supplier SupplierCity Part PartQuantity PartColour

Table is now in 1NF 2NF Step 1: Write each key component on a separate line Supplier Part Supplier, Part

Step 2: Assign Corresponding Dependent Attributes Supplier(Supplier, SupplierCity) Part(Part, PartColour) SupplierPart(Supplier, Part, PartQuantity)

Table is in second normal form because it is in 1NF and includes no partial dependencies. 3NF Step 1: Identify Each New Determinant There are no determinants Step 2: Identify the Dependent Attributes There are no determinants with dependent attributes Step 3: Remove the Dependent Attributes from Transitive Dependencies There are no transitive dependencies Table is in 3NF because it is in 2NF and has no transitive dependencies

Refined ERD: Supplier PK SupplierName

SupplierPart PK SupplierName SupplierPartQuantity

PK Part_Id

Part PK Part_Id ColourId

Cit yId 1.. 1 suppli es > 1. .* 1. .*

1.. 1

supplied by >

C it yId

C it y PK Cit yId Cit yNa me

Colour PK ColourId ColourName

  1. .* 1.. 1

si tu ate d in >

  1. .* 1.. 1has >

Question 2 1NF Step 1: Eliminate repeating groups There are no repeating groups Step 2: Identify the primary key Emp_id, emp_dept Step 3: Assign dependencies Draw dependency diagrams, for simplicity I will just show the relational schemas with dependencies Emp_id, emp_dep ->emp_name, emp_city, dept_name, job_code, job_desc Partial dependencies: Emp_id->emp_name, emp_city Emp_dept->dept_name Transitive dependencies Job_code->job_desc Table is in 1NF 2NF Step 1: Write down each key component on a separate line Emp_id Emp_dept Emp_id, emp_dept Step 2: Assign Corresponding Dependent Attributes EMPLOYEE(Emp_id, emp_name, emp_city) DEPARTMENT(Emp_dept, dept_name) EMPLOYEEDEPARTMENT(Emp_id, emp_dept, job_code, job_desc)

Table is in 2NF because it is in 1NF and there are no partial dependencies 3NF

Step 1: Identify Each New Determinant Job_code Step 2: Identify the Dependent Attributes Job_code->job_desc Step 3: Remove the Dependent Attributes from Transitive Dependencies EMPLOYEE(Emp_id, emp_name, emp_city) DEPARTMENT(Emp_dept, dept_name) EMPLOYEEDEPARTMENT(Emp_id, emp_dept, job_code) JOB(job_code, job_desc) Table is in 3NF because it is in 2NF and has no transitive dependencies Question 3 Follow the normalisations steps and see if you end up with the following schemas: TEACHER(TEACHERID, TEACHERNAME, TEACHERSURNAME) SUBJECT(SUBJECTCODE, SUBJECTNAME, TEACHERID, VENUECODE) VENUE(VENUECODE, VENUENAME)

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Worksheet Chapter 7 - Memo

Course: Introduction to Databases and Databases Management Systems:Part 1 (CSIQ2634)

37 Documents
Students shared 37 documents in this course

University: University of the Free State

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UNIVERSITY OF THE FREE STATE
Department of Computer Science
and Informatics
CSIS2634
Worksheet (Chapter 7)
Question 1
1NF
Step 1: Eliminate repeating groups:
Supplier
Supplier City
Part
Part Quantity
Part Colour
Sup1
Cape Town
ABCB123
12
Grey
Sup1
Cape Town
JKU87
10
Yellow
Sup1
Cape Town
FDGE65
5
Blue
Sup2
Johannesburg
JKU87
3
Yellow
Sup3
Cape Town
ABCB123
4
Grey
Sup3
Cape Town
GHSD789
2
Grey
Step 2: Identify the primary key
Supplier, Part
Step 3: Identify all dependencies
Supplier
SupplierCity
Part
PartQuantity
PartColour
Table is now in 1NF
2NF
Step 1: Write each key component on a separate line
Supplier
Part
Supplier, Part

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