need to create an entity-relationship diagram. Please follow from the work already done in new assignment x
Description of data requirements of the new system. You must provide:
a. An ER Diagram
b. A description of the entities and their attributes.
1.
Apply appropriate problem solving processes based on logical and critical thinking and systems modelling to produce the system’s scope, analyse system requirements and design potential information system solutions.
2.
Prepare a business case for a proposed business problem solution and produce a suitable system specification report.
Case Study – Personnel Self-Service System (PSS)
Background
Sales Corporation (SC) has approximately 3000 personnel. SC has experienced a 10 percent increase in personnel over the past two years, and long-range projections show that trend continuing for the next three years.
Ron Taylor, the Human Resources (HR) director, is thinking of putting in place a Personnel Self-Service System (PSS) that will provide the capability for personnel to maintain some personal information so that it is accurate and up to date. The PSS should also allow personnel to only view but not change other information.
Current practices now have each of the changes to personal information being processed by an extensive manual effort in which personnel fill out forms and HR personnel then input the data into the HR system. This manual effort often results in a time lag of a few days between the time personnel submit the forms and the update of the information in the HR system. This delay has caused several problems, including mail being sent to the wrong address. Another problem of the present system is the intranet-based personnel directory, which is out-of-date with incorrect information on personnel who have changed addresses or been transferred to another department.
The plan for the new system is to provide the capability for personnel to update data themselves in real time reducing if not eliminating the problems mentioned above. The intranet-based personnel directory will be always up-to-date.
Tom Gayle, a systems analyst from your consulting firm, has done some preliminary investigation (through interviews) with Ron Taylor (HR Director) and Joan Whitford, (HR Manager), and this is the information he has gathered so far:
Information gathered from interview with Ron Taylor
It appears that there are a lot of inefficiencies in the current system and its operating costs are excessive. The current system itself is a combination of manual and automated processes. The automated processes reside in the legacy system. Ron thinks it is too costly and risky to get rid of the current legacy system. They are currently concentrating on reengineering the current HR System to meet their needs.
Ron said that personnel go through an orientation program on their first day of work. During that program they are required to complete some personnel forms that include information such as addresses, phone numbers and emergency contact information. HR personnel then input the data into the legacy system.
The personnel directory, sort of a telephone book, consists of the job title, work telephone number and location, and department of personnel. Because SC is such a dynamic and growing organisation, Alicia, a HR personnel, spends quite a bit of her time maintaining the information. However, as SC is a large and growing organisation, the directory is usually out of date as at least one person is hired or transferred, moves departments, or is terminated daily. These events all require a change to the directory.
Currently only HR personnel can directly use the HR system. Ron would like to see that changed so that personnel can be responsible for maintaining some of their own personal information e.g. maintaining their own address or contact details. The data would be more current and it would reduce the labor support in HR. Currently, to process each change in personnel information costs about $15 in labor and computing costs and 1,500 changes were processed last year alone, which is quite substantial. Everyone in the institution uses a PC and Ron feels that personnel should also be able to access and change their information from the office and home via the Web.
Ron envisions a PSS that is easy to use, intuitive, with a graphical user interface. It should be accessible from every desktop in SC and from home via the Web. The interface should have a folder metaphor. For example, if one were a staff member entering the system, one would be presented with a series of folders or tabs. Each folder would consist of a certain type of information, such as personal information, leave application and training.
Information gathered from interviews with Joan Whitford
The following information was gathered by Tom in his interviews with Joan.
Besides allowing personnel to maintain some of their own personal information, Joan is thinking of allowing personnel to manage their leave, check leave balances and view previous leave taken. Personnel should also be able to apply for internal personnel training courses offered by SC, and to view the courses they have attended.
Personnel should be able to view their qualifications, current and previous job appointment details within SC. However all changes to a personnel member’s job or qualification still require paperwork that has to go through HR.
Joan wants the directory to show the contact, work location, department, organisational unit, and job title of personnel. It should be driven by some sort of search screen e.g. search by first or last name or combinations of them. This is confidential information that cannot be open to the public.
The information that the system requires is as follows:
a) Personnel ID and name, work location, department, home and work phone, address, job title (including its start and end date), organisational area, qualification title, qualification major, completion date, institution and country where qualification was obtained, and title, name, relationship, address and contact number of emergency contacts.
b) The internal training courses attended and the date attended
c) The type of leave taken, start date and end date, whether a medical certificate has been provided, and the option to put in a comment. If the personnel has a medical certificate, there must be a facility to upload the certificate.
Information about the internal training courses offered and their duration, list of qualifications, organisational areas and jobs is maintained by Human Resource personnel.
Assignment Requirements
Unfortunately, Tom has left the organisation and you, as a trainee systems analyst in the IT department, have been asked by your manager to finish the job. By analysing the information gathered from the interviews and using appropriate fact-finding techniques, prepare a Functional Requirements Report
The format for the report is detailed below.
1. Description of data requirements of the new system. You must provide:
a. An ER Diagram
b. The name, description and an example of the data stored in each of the attributes for each entity of interest to the system and relationship (where applicable). You can make some reasonable assumptions when describing the attributes. You must indicate which attribute is the identifier for each entity.
Note: Each report should have control breaks where applicable and the data should be sorted.
Appendix
4
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Chapter 4
Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
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2
Domain Modeling
Systems Analysis and Design in a Changing World 7th Ed
Satzinger, Jackson & Burd
Chapter 4
Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
3
Chapter 4 Outline
“Things” in the Problem Domain
The Entity-Relationship Diagram
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
4
Learning Objectives
Explain how the concept of “things” in the problem domain also define requirements
Read and interpret an entity-relationship diagram
Identify and analyze data entities needed in the system
Create an entity-relationship diagram
Student Learning Outcome
Use appropriate techniques and tools to construct models for existing and new systems.
Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
5
Overview
Chapter 3 provided an overview of identifying use cases to define functional requirements
This chapter focuses on another key concept for defining information/data requirements which is the concept of data entities.
Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
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Systems Analysis and Design in a Changing World, 6th Edition
7
Requirements Models in this unit
Model covered in this lecture
Models covered in previous lecture
Themes for Information-Elicitation Questions
and their associated models
Systems Analysis and Design in a Changing World, 7th Edition
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ERD
Use Case Models
8
The first questions that new systems analysts ask are, “What kind of information do I need to collect?” and “What is a requirement?” Basically, you want to obtain information that will enable you to build the logical model of the new business system (see Chapters 5 and 6 for information about modeling). As shown in Figure 4-6, the following three major themes should guide you as you pursue your investigation:
What Are the Business Processes?
In the first question—What do you do?—the focus is on understanding the business functions. In most cases, the users will provide answers in terms of the current system. As an analyst, you must carefully discern which of those functions are fundamental business functions, which will remain, and which may possibly be eliminated with an improved system.
How is the Business Process Performed?
The second question—How can it be done?—moves the discussion from the current system to the new system. The focus is on how the new system should support the function rather than on how it is performed under the existing system. Thus, the first two questions go hand-in-hand to discover the need and begin the definition of the system requirements in terms of the new system.
What Information is Required?
The final question—What information is needed?—defines specific information that the new system must provide. The answers to the second and third questions form the basis for the definition of the system requirements.
If you focus your investigation around these three themes, you will be able to ask intelligent, meaningful questions in your investigation. Later, as you learn about models, you will be able to formulate additional meaningful detailed questions to ask.
Systems Analysis and Design in a Changing World, 7th Edition
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Entity-Relationship Diagram (ERD)
An ERD
is one model that represents data of interest to the system
basically shows the same information as a domain model Class Diagram (a UML model)
is used widely in database design
has no standard notation
crows feet notation is used in this text
consists of:
entities
relationships (associations) and
attributes
Systems Analysis and Design in a Changing World
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Example of an ERD for a Customer Account System
Entity
Attribute
Relationship
Entities
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
1. Entity
“Thing” of interest that the system needs to store information about.
For example, a Student Management System needs to store data about a thing (entity) called student.
Represented by a rectangle in an ERD.
The name given to an entity MUST be SINGULAR and must be a NOUN e.g.
12
STUDENT
12
Entity Set & Entity Instance
An entity instance is each unique identifiable “thing” within an entity set.
For example, the STUDENT entity set below contains 2 unique identifiable student entity instances.
STUDENT entity set (with 2 instances)
Student ID Surname Firstname DOB Phone
123456789 Bloggs Joe 16/06/1981 93321245
123456790 Smith Jim 17/07/1975 94567556
STUDENT
ENTITY
StudentID
Surname
Firstname
DOB
Phone
Identifying Entities of interest to a system
Consider the following scenario for a bank’s account transaction processing system:
Kevin, a customer goes into the bank and makes a deposit. The bank teller at the counter records details of Kevin’s deposit.
What are the entities (things) of interest to the bank’s account transaction processing system in the scenario above? Which entities would the system need to keep information about?
Relationships
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
2. Relationship
Relationship – naturally occurring association between entities
Represented by a
line connecting the entities participating in the relationship and
a verb describing the relationship
CUSTOMER
ORDER
places
ITEM
contains
Read them separately each way e.g. the relationships between Customer and Order are:
Customer “places” Order (left to right) and
Order “is placed by” Customer (right to left).
17
Explaining relationships (associations) using entity instances
Order instance
Customer instance
Item instances
Representing business rules (cardinality)
We need to represent business rules i.e. the number of associations between entity instances participating in a relationship in an ERD
This is referred to as the cardinality of the relationship.
For example, what do you think are the business rules for the 2 relationships shown in the ERD below?
CUSTOMER
ORDER
places
ITEM
contains
Systems Analysis and Design in a Changing World, 7th Edition
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Representing business rules (cont’d)
During elicitation of requirements, the following 3 business rules were expressed by the user with regard to customers placing orders for items.
Fig 4-5
1.
2.
3.
Systems Analysis and Design in a Changing World, 7th Edition
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Representing business rules (cont’d)
The notation (crows feet) used to represent the cardinality of
relationships is shown below:
Representing business rules (cont’d)
The cardinality of the relationships have been added to the ERD based on the business rules expressed by the user
CUSTOMER
ORDER
places
ITEM
contains
What do you think should be the business rule and cardinality for this end of the relationship?
Business
Rule 2
Business
Rule 1
Business
Rule 3
Systems Analysis and Design in a Changing World, 7th Edition
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Business Rule 1:
A customer places zero or many orders
Explaining cardinality using
Customer, Order and Item (Product) instances
Business Rule 4:
An order contains one or more items
Customer places many orders
Customer places zero orders
Customer places one order
STUDENT
UNIT
Determining business rules between entities
enrols
You can determine the business rules between entities by asking 4 questions (in this example let’s examine the relationship Student enrols in Unit):
In how many units can a student enrol? Answer: many
Must a student enrol in a unit? Answer: mandatory
How many student enrolments can a unit have? Answer: many
Must a unit have a student enrolment? Answer: optional
EMPLOYEE
PROJECT
Describe the cardinality of the following
one-to-one relationship:
Example of an ERD with a
One-to-One (1:1) Relationship
manages
EMPLOYEE
PROJECT
Describe the cardinality of the following
one-to-many relationship:
Example of an ERD with a
One-to-Many (1:M) Relationship
manages
STUDENT
UNIT
Describe the cardinality of the following
many-to-many relationship:
Example of an ERD with a
Many-to-Many (M:N) Relationship
enrols in
Example of Multiple Relationships
DEPT
*deptname
deptlocation
EMP
*empno
empfname
emplname
is assigned
is managed by
Describe the cardinality of the following relationships:
Hoffer J. A., George J. F., & Valacich S. Modern Systems Analysis and Design
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Degree of Relationships (Associations)
Binary
a relationship between entity instances from 2 entity sets e.g. a product line contains many products
Unary Association (recursive)
a relationship between entity instances within the same entity set e.g.
A person is married to another person or an employee manages many employees
Binary relationships are relationships between two different types of things, such as a customer and an order.
Unary (recursive) relationships are relationships between two things of the same type, such as one person being married to another person.
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Hoffer J. A., George J. F., & Valacich S. Modern Systems Analysis and Design
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Degree of Relationships (Cont’d)
Ternary Association (three)
a simultaneous relationship among instances from 3 entity sets e.g. vendors ships parts to warehouses
N-ary Association (between n)
Ternary relationships are relationships between three different types of things. (An n-ary relationship means a relationship between n, any number, of different types of things.)
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Attributes
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
3. Attribute
A specific piece of information stored about an entity or a relationship
An attribute describes an entity or a relationship
Naming attributes:
must be unique within an entity or a relationship
must be a noun
must be singular
should be meaningful
Important: An entity should only contain attributes that describe that entity i.e. it should not contain attributes that describe other entities.
Attributes
customer_id
first_name
last_name
phone_no
CUSTOMER
Most information systems store and use specific pieces of information about each thing. One piece of information about a thing is called an attribute.
For example, a customer has a name, address, phone number, and so on.
Sometimes the identifier or key might be a compound attribute
Systems Analysis and Design in a Changing World, 7th Edition
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Attributes and Values
Three customer instances
Attributes store data values
Example of an attribute describing a Relationship
Systems Analysis and Design in a Changing World, 7th Edition
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Figure 4-15
grade
enrols
contains
33
Many-to-many relationships have “crow’s feet” on both ends of the relationship line. Sometimes this means there is more information that needs to be stored about the relationship. For example, a course section enrolls many students, and a student is enrolled in many course sections.
An associative entity called Course enrollment should replace the many-to-many relationship to allow the system to store the grade for each section that is taken by the student. See Figure 5-28 on page 178.
Type of Attribute Classifications
Simple versus Compound (Composite)
e.g. name is a compound attribute made up of simple attributes like first and last (family) name.
Single-valued versus Multi-valued
e.g. sex has a single value i.e. M or F but contact number could have multiple values e.g. home phone number, mobile number etc.
Stored versus Derived Attributes
e.g. Date of birth is a stored attribute while age is a derived attribute
Hoffer J. A., George J. F., & Valacich S. Modern Systems Analysis and Design
5
A compound attribute is an attribute that contains a collection of related attributes. For example, a Customer full name compound attribute might represent a customer’s first, middle, and last names.
Identifier
Every entity set must have an attribute or set of attributes that uniquely identifies each entity instance
e.g. the attribute cust_number uniquely identifies each customer instance for the entity CUSTOMER.
This attribute or set of attributes is called an identifier.
In this text, the characters “PK” is used to denote an identifier (placed in front of the identifier)
Each customer has a specific value for the attribute that is important for the system to remember. An attribute that uniquely identifies a specific thing is called an identifier or key. For example, an identifier for a customer is a customer number, for a vehicle it is a vehicle ID, and for a product it is a product ID. Sometimes these identifiers already exist (social security number, vehicle ID number) but sometimes they need to be created and assigned by the system (invoice number, transaction number).
Not all identifiers are ID numbers. For example, a name of a university could be an identifier.
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An ERD for a Customer Account System (with attributes)
Identifier (PK)
Guidelines for Choosing an Identifier
Candidate Identifier – any attribute or set of attributes that could be used as an identifier i.e. they satisfy the requirements for being an identifier, e.g. studentid or email address can uniquely a student
When choosing the identifier for an entity, choose one that:
will always have a value
will not change its value over time
will not lose its uniqueness
is short.
Each customer has a specific value for the attribute that is important for the system to remember. An attribute that uniquely identifies a specific thing is called an identifier or key. For example, an identifier for a customer is a customer number, for a vehicle it is a vehicle ID, and for a product it is a product ID. Sometimes these identifiers already exist (social security number, vehicle ID number) but sometimes they need to be created and assigned by the system (invoice number, transaction number).
Not all identifiers are ID numbers. For example, a name of a university could be an identifier.
Developing an ERD
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
Process for Developing an ERD
Step 1a: Identify entities
Step 1b: Identify attributes for the entities
Some sources of information to identify entities and attributes include:
event tables
trigger for external events – input data (attributes)
response – output data (attributes)
use case descriptions
current reports or forms
information from existing systems and current procedures
Systems Analysis and Design in a Changing World, 7th Edition
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RMO Event Table (trigger and response)
Systems Analysis and Design in a Changing World, 5th Edition
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Systems Analysis and Design in a Changing World, 7th Edition
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Use Case Description
Entities
Sample Order Form for RMO
Systems Analysis and Design in a Changing World, 7th Edition
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Payment attributes
Order item attributes
Customer attributes
Shipment attributes
42
Better to have a completed rather than a blank form because:
Can see how form is actually used and understand the data
Can determine type and size of data being recorded
Need to determine which data is not always required
Can see relationships between data on form
Process for Developing an ERD (cont’d)
Step 2a: Identify relationships between the entities e.g.
Customer makes an Order
Order contains Items
Step 2b Identify cardinalities (business rules) of the relationships e.g.
Customer must make one or more Orders
Order must contain one or more items
Step 3: Identify any attributes for the relationships
Note: The process is an iterative and incremental process e.g. after step 3, one might identify attributes that describe entities that were not identified in step 1. One would then go back to step 1 and start again.
Systems Analysis and Design in a Changing World, 7th Edition
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43
ERD Exercise
Every school in a university has a large number of units in its courses. After a student is admitted into a course, the student enrols in one or more units in a semester. A student might not be enrolled in any units in a particular semester (e.g. having a holiday, leave of absence or suspended).
ENROLMENT REPORT
Student ID: 143589 Name: John Smith
School Name: Management
Course Code: BOC Course Name: Bachelor of Commerce
Year Admitted: 2014
Year: 2014 Semester: 1
Unit ID Unit Name
11739 Development Methods
310410 Systems Analysis 251
44
Step 1a – Identify entities
Every school in a university has a large number of units in its courses. After a student is admitted into a course, the student enrols in one or more units in a semester. A student might not be enrolled in any units in a particular semester (e.g. having a holiday, leave of absence or suspended).
ENROLMENT REPORT
Student ID: 143589 Name: John Smith
School Name: Management
Course Code: BOC Course Name: Bachelor of Commerce
Year Admitted: 2014
Year: 2014 Semester: 1
Unit ID Unit Name
11739 Development Methods
310410 Systems Analysis 251
45
Step 1a – Identify entities (cont’d)
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
SCHOOL
COURSE
STUDENT
UNIT
Step 1b – Identify attributes for entities
Every school in a university has a large number of units in its courses. After a student is admitted into a course, the student enrols in one or more units in a semester. A student might not be enrolled in any units in a particular semester (e.g. having a holiday, leave of absence or suspended).
ENROLMENT REPORT
Student ID: 143589 Name: John Smith
School Name: Management
Course Code: BOC Course Name: Bachelor of Commerce
Year Admitted: 2014
Year: 2014 Semester: 1
Unit ID Unit Name
11739 Development Methods
310410 Systems Analysis 251
47
Step 1b – Identify attributes for entities (cont’d)
48
Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
SCHOOL
SchoolCode (I)
SchoolName
COURSE
CourseCode (I)
CourseName
STUDENT
StudentNo (I)
StudentlName
UNIT
UnitID (I)
UnitName
Step 2a – Identify relationships
Every school in a university has a large number of units in its courses. After a student is admitted into a course, the student enrols in one or more units in a semester. A student might not be enrolled in any units in a particular semester (e.g. having a holiday, leave of absence or suspended).
ENROLMENT REPORT
Student ID: 143589 Name: John Smith
School: Management
Course Code: BOC Course Name: Bachelor of Commerce
Year Admitted: 2014
Year: 2014 Semester: 1
Unit ID Unit Name
11739 Development Methods
310410 Systems Analysis 251
49
Step 2a: Identify relationships (cont’d)
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
SCHOOL
SchoolCode (I)
SchoolName
COURSE
CourseCode (I)
CourseName
STUDENT
StudentNo (I)
StudentlName
UNIT
UnitID (I)
UnitName
admits
enrols
offers
consists
Step 2b – Identify cardinalities
Every school in a university has a large number of units in its courses. After a student is admitted into a course, the student enrols in one or more units in a semester. A student might not be enrolled in any units in a particular semester (e.g. having a holiday, leave of absence or suspended).
ENROLMENT REPORT
Student ID: 143589 Name: John Smith
School: Management
Course Code: BOC Course Name: Bachelor of Commerce
Year Admitted: 2014
Year: 2014 Semester: 1
Unit ID Unit Name
11739 Development Methods
310410 Systems Analysis 251
51
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
SCHOOL
SchoolCode (I)
SchoolName
COURSE
CourseCode (I)
CourseName
STUDENT
StudentNo (I)
StudentlName
UNIT
UnitID (I)
UnitName
admits
enrols
offers
consists
Step 2b – Identify cardinalities (cont’d)
Step 3 – Identify attributes for relationships
Every school in a university has a large number of units in its courses. After a student is admitted into a course, the student enrols in one or more units in a semester. A student might not be enrolled in any units in a particular semester (e.g. having a holiday, leave of absence or suspended).
ENROLMENT REPORT
Student ID: 143589 Name: John Smith
School: Management
Course Code: BOC Course Name: Bachelor of Commerce
Year Admitted: 2014
Year: 2014 Semester: 1
Unit ID Unit Name
11739 Development Methods
310410 Systems Analysis 251
53
Step 3 – Identify attributes for relationships (cont’d)
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
SCHOOL
SchoolCode (I)
SchoolName
COURSE
CourseCode (I)
CourseName
STUDENT
StudentNo (I)
StudentlName
UNIT
UnitID (I)
UnitName
Year
Semester
Year
Admitted
admits
enrols
offers
consists
ERD
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
SCHOOL
SchoolCode (I)
SchoolName
COURSE
CourseCode (I)
CourseName
STUDENT
StudentNo (I)
StudentlName
UNIT
UnitID (I)
UnitName
Year
Semester
Year
admits
enrols
offers
contains
Supertypes and Subtypes
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
More Complex Concepts
Generalisation: The concept that some entities are subtypes of other, more general entities i.e. supertypes.
A supertype is a generic entity type that is subdivided into subtypes
e.g. the “Motor Vehicle” in the next slide is considered a supertype that is subdivided into 3 subtypes (Truck, Car and Tractor).
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57
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More Complex Concepts (cont’d)
More Complex Concepts (cont’d)
A subtype shares common attributes or relationships with other subtypes but also has its own distinct attributes
For example, an organisation has 3 types (subtypes) of employees:
1. Casual Employees: EmpNo, Name and Hourly Rate
2. Salaried Employees EmpNo, Name and Annual Salary
3. Contract Consultants: EmpNo, Name, Contract No and Daily Rate
The employee subtypes above
Share common attributes i.e. EmpNo and Name and
Have their own distinct attributes (in italics).
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59
The scenario in the previous slide can be modelled using 3 approaches:
Approach 1: Define one entity EMPLOYEE that stores all the attributes
Approach 2: Define 3 separate entities: CASUAL EMP, SALARIED EMP and CONSULTANT
Approach 3: Define a supertype EMPLOYEE (that stores the common attributes) with subtypes CASUAL EMP, SALARIED EMP and CONSULTANT which store the attributes unique to that subtype.
Modelling supertype and subtypes
EMPLOYEE
EmpNo
Name
Hourly rate
Annual Salary
ContractNo
DailyRate
Approach 1
Define one entity EMPLOYEE that stores the attributes for all types of employees
Approach 1 (cont’d)
EmpNo Name Hourly rate Annual Salary ContractNo
DailyRate
01 Smith 70
02 Jones 80000
03 Tan 0897889 900
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Systems Analysis and Design in a Changing World, 7th Edition – Chapter 4 ©2016. Cengage Learning. All rights reserved.
Note: There will no values (nulls) stored in the attributes Hourly Rate, Annual Salary, ContractNo and DailyRate, as these are unique attributes that will only have values depending on the type of employee i.e. casual, salaried or contract.
CASUAL_EMP
EmpNo
Name
Hourly rate
SALARIED_EMP
EmpNo
Name
Annual Salary
CONSULTANT
EmpNo
Name
ContractNo
DailyRate
Approach 2
Note: This approach is not making use of the common attributes (EmpNo and Name) for each of the entities.
Define 3 separate entities: CASUAL EMP, SALARIED EMP and CONSULTANT
EMPLOYEE
EmpNo
Name
CASUAL
EMP
Hourly rate
SALARIED
EMP
Annual Salary
CONSULTANT
Contract
DailyRate
Approach 3 – Using super and subtypes
Note:
This approach makes use of the common attributes (EmpNo and Name) applicable to all types of employees (which was the issue in approach 2)
All attributes of the supertype become attributes of its subtypes i.e. the subtypes CASUAL EMP, SALARIED EMP and CONSULTANT inherit the attributes EmpNo and Name from the supertype EMPLOYEE.
This approach also avoids the situation of no values (nulls) being stored in the attributes Hourly Rate, Annual Salary, ContractNo and DailyRate (which was the issue in approach 1).
Systems Analysis and Design in a Changing World, 7th Edition
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Summary
This chapter focuses on modelling data requirements as a part of systems analysis
“Things” are identified and modelled, called data entities
Data entities have attributes and associations
Associations are naturally occurring relationships among entities, and have minimum and maximum cardinality
Entity-relationship diagrams (ERDs) show the information about data entities and their associations
References
Hoffer J. A., George J. F., & Valacich S. Modern Systems Analysis and Design, Pearson Prentice Hall.
Systems Analysis and Design in a Changing World, 6th Edition
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Additional Exercises
Additional exercises on Use Cases can be found in the appropriate chapters in the following textbooks in the library:
1. Bentley, L.D. and Whitten, J. L. (2007). Systems Analysis and Design for the Global Enterprise, 7th Ed., McGraw-Hill/Irwin, McGraw-Hill Companies.
2. Hoffer J. A, Valacich S., George J. F. (2013). Modern Systems Analysis and Design, 7th Ed., Pearson Prentice Hall.
3. Shelly, G.B., Cashman, T.J., & Rosenblatt, H.J. 2012. Systems Analysis and Design, 9th ed., Thomson Course Technology.
4. Kendall, K.E. and Kendall, J.E., (2013), Systems Analysis and Design, 9th ed., Pearson Prentice Hall.
5. Dennis, A., Wixom, B. H. & Roth, R.M. (2014). Systems Analysis and Design, 6th ed., John Wiley & Sons Inc.
1. Needs and/or Problem description, and proposed solution (system capabilities) of new system
Systems Analysis and Design in a Changing World, 6th Edition
2
Example of a Problem Description
Chapter 9
2
Systems Analysis and Design in a Changing World, 6th Edition
3
Example of System capabilities
Chapter 9
3
2. Description of functionality of the new system.
Example of a Use Case Glossary
Use case number Use case name Brief Description Actors
1 Create new order When a customer calls to order, the order clerk verifies the customer information, creates a new order, adds items to the order, creates the order transaction and finalises the order Order clerk
Note: You must number your use cases
More examples – Brief use case description
Systems Analysis and Design in a Changing World, 7th edition – Chapter 5 ©2016. Cengage Learning. All rights reserved.
6
3. Description of data requirements of the new system.
ERD and Attribute Description
Example of an ERD
Systems Analysis and Design in a Changing World, 7th Edition – Chapter 8 ©2016. Cengage Learning. All rights reserved.
Example of an Attribute Description for one entity or relationship (where applicable)
Attribute Name Description Example of Data
cust_number (I) Customer’s Identification Number 15462316
name Name of customer Acme
mobilephone Customer’s mobile phone number 0413786788
homephone Customer’s home phone number 96578455
email_address Customer’s email address acme@acme.com.au
Name of Entity or Relationship: CUSTOMER
Integration of Analysis and Design models
All the models created in this assignment (Use Cases, ERD, User interface screen design and Output Report design) must:
be consistent and
integrate together to provide a complete picture of the requirements and specification.
Systems Analysis and Design in a Changing World, 7th edition
©2016. Cengage Learning. All rights reserved.
10
Table
of Contents
Problem/Needs Description 1
Proposed Solution 1
Description of System (Use Cases) 1
ER Diagrams
1
Description of Entities
1
No table of figures entries found.
David De Villiers (15110266) |
Raghav
Choudhary
(18961645) | Scott Stewart (18783373)
3
1. Problem/Needs Description
Sales Corporation (SC) is fast growing company which has approximately 3000 personnel and has grown by 10% in the last two years, Sales Corporation foresee this trend continuing for the next three years. Currently, Sales Corporation have an extensive manual system which is used to change personal information for personnel via the HR department who require staff to fill out forms and then submit to HR who update the information via the HR system. This manual system causes many issues within the business, this is due to the time it takes to update the system (which is usually a few days) as once the information has been updated it may be already out of date, this causes may issues when mail is sent it incorrect address’s. Due to the size and continuing growth of Sales Corporation Ron Taylor (HR Director) and Joan Whitford (HR Manager) would like to implement a web based system whereby personnel can update their own personal information, thus reducing/eliminating the business issues currently experienced by Sales Corporation and the HR Department.
2. Proposed Solution/System Capabilities
The below outlines the new systems capabilities and proposed solutions which will help mitigate the current HR issues at Sales Corporation.
· Allow Sales Corporation personnel to access HR system via website.
· Display: Personnel ID number, name, work location, department, job title (Start and
End
dates for positions held at Sales Corporation).
· Allow Sales Corporation personnel to update personal information I.E: Address, phone number, emergency contact information (Relationship, name, address, phone number).
· Display organizational area, qualification title, qualification major (completion date, institution and country of obtained qualification) Note: Changes to this will still require some paperwork to go to HR.
· Allow Sales Corporation personnel to manage personal leave, apply for leave, check leave balance
· Display previous leave taken (start & end date of leave), type of leave taken (personal leave, sick leave, jury leave etc.)
· Allow Sales Corporation personnel to upload medical certificates, option to provide comments.
· Allow Sales Corporation personnel to apply for internal training courses
· Display previous training courses attended/completed.
· Display current position and previous positions held within Sales Corporation.
3. Description of System (Use Cases)
Use Case Number
Use Case Name
Description
Actors
1.
Create new employee ID
On the first day of work a new employee would input all their personal information via a form and would have a personnel ID generated.
New SC personnel/HR Staff
2.
Input new Employee information
HR would then input new personnel information into system (I.E: Name, address, phone number, emergency contact information, work location, department, organizational unit, qualification title, qualification major, completion date, institution and country where qualification was obtained.
HR Staff
3.
Email link to employee
The PPS system would email the new SC personnel with a link to the website along with their I.D number which would be there username along with a temporary password. They would sign into the Self-Service system and create a new password.
HR staff/New personnel
4.
Personnel login in system
Personnel would login in and check leave balance, apply for leave, view previous leave taken, view qualifications, current and previous positions.
SC Personnel
5.
Apply for internal personnel training courses.
SC Personnel can login into the PPS to view and apply for internal training courses which are offered by Sales Corporation.
SC Personnel
6.
Display staff directory
SC staff would be able to view a personnel directory which displays qualifications, work location, department, organizational unit and job title.
SC Personnel
ER Diagrams
Description of Entities
References
0
Appendix
Assignment Plan
Assignment Progress Reports
INTRODUCTORY SAD – ASSIGNMENT 2020 SEMESTER 1
GROUP WORK ALLOCATION PLAN
Student Names: David De Villiers 15110266
Raghav Choudhary 1896164
5
Group Leader: Scott Stewart 18783373
Section
Will be done by
Planned
Start
Date
Planned
End
Date
Marks
Need/Problem description
Proposed solution (system
capabilities/functionality)
David De Villiers 09/04/2020 15/04/2020 5
5
Major use cases and their descriptions.
You must provide a use-case glossary (that
shows the name of each use case, a brief
description of the use case and the actors
for the use case).
David De Villiers 15/04/2020 30/04/2020
54
Description of data requirements of the
new system. You must provide:
a. An ER Diagram
b. A description of the entities
and their attributes.
Raghav
Choudhary
15/04/2020 15/05/2020
33
27
Design of input screen(s) and flow of
activities for 3 use cases
Scott Stewart 20/04/2020 04/05/2020 36
Design of output reports for 3 use cases
Scott Stewart 04/05/2020 18/05/2020 30
Compilation and presentation quality of
report
Scott Stewart &
Raghav
Choudhary
27/05/2020 30/05/2020 10
Signed group plan and progress reports
TOTAL
200
Note: The group members (and not the tutor) are responsible for ensuring that members
contribute equally to the assignment
Signature of group members: Date: 03/04/2020
David De Villiers Raghav Choudhary Scott Stewart
Tutor’s signature:
INTRODUCTORY SAD – ASSIGNMENT 2020 SEMESTER 1
GROUP WORK ALLOCATION PLAN
Student Names: David De Villiers 15110266
Raghav Choudhary 18961645
Group Leader: Scott Stewart 18783373
Section
Will be done by
Planned
Start
Date
Planned
End
Date
Marks
Need/Problem description
Proposed solution (system
capabilities/functionality)
David De Villiers 09/04/2020 15/04/2020 5
5
Major use cases and their descriptions.
You must provide a use-case glossary (that
shows the name of each use case, a brief
description of the use case and the actors
for the use case).
David De Villiers 15/04/2020 30/04/2020
54
Description of data requirements of the
new system. You must provide:
a. An ER Diagram
b. A description of the entities
and their attributes.
Raghav
Choudhary
15/04/2020 15/05/2020
33
27
Design of input screen(s) and flow of
activities for 3 use cases
Scott Stewart 20/04/2020 04/05/2020 36
Design of output reports for 3 use cases
Scott Stewart 04/05/2020 18/05/2020 30
Compilation and presentation quality of
report
Scott Stewart &
Raghav
Choudhary
27/05/2020 30/05/2020 10
Signed group plan and progress reports
TOTAL
200
Note: The group members (and not the tutor) are responsible for ensuring that members
contribute equally to the assignment
Signature of group members: Date: 03/04/2020
David De Villiers Raghav Choudhary Scott Stewart
Tutor’s signature: