TCS - Milestone 3 Data Modeling and Analysis

					System development for TCS - Milestone 3: Data Modeling                                    Page 3-1




MILESTONE 3 – DATA MODELING AND ANALYSIS


 Synopsis
The requirements analysis phase answers the question, ―What does the user need and want from a
new system?‖ The requirements analysis phase is critical to the success of any new information
system! In this milestone we need to identify what information systems requirements need to be
defined from the system users’ perspectives and draw graphical, logical models to document the
data requirements for a new and improved system.
Data modeling is a technique for organizing and documenting a system’s data. Data modeling is
sometimes called database modeling because a data model is usually implemented as a database.
Data is viewed as a resource to be shared by as many processes as possible. As a result, data must be
organized in a way that is flexible and adaptable to unanticipated business requirements – and that is
the purpose of data modeling.
In this milestone you will first discover those entities in the system that are or might be described by
data. Then we will define each entity we identify in respect to the business. Then we will construct a
Context Data Model that graphically depicts each of the entities and their relationships with each
other. Next, we will refine the context data model to include primary and foreign keys. The resulting
model is called a Key-Based Data Model. Finally, we refine the key-based data model to include any
hierarchies and attributes, and this model is referred to as the Fully Attributed Data Model.

 Objectives
After completing this milestone, you should be able to

 Understand and perform the techniques for entity discovery.
 Define each entity with respect to the business and complete an entity definition matrix.
 Perform the necessary data modeling techniques to organize and document the data
  requirements for the proposed system.
 Construct the Context, Key-Based, and Fully Attributed data models.

Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed
System development for TCS - Milestone 3: Data Modeling                                 Page 3-2

 Prerequisites
Before starting this milestone the following topics should be covered:
    1. Data modeling — Chapter 7.
    2. Milestone 2 solution.

 Assignment
Now that we have studied the current system and analyzed some of its problems and opportunities,
plus gained approval to proceed, we can now start to identify the business data requirements and
graphically model them. In this assignment we will use our results of the previous Milestone,
samples of forms we have collected, and a copy of a transcript of an interview with Al Borland’s
staff. The results of this activity will identify the business data requirements for the proposed
system.

 Activities
1. Complete an Entity Definition Matrix. Analyze each of the forms referenced by the user
   interview and make assumptions where necessary. (Note: while it is appropriate to make
   assumptions, you should document those assumptions and include them in your submission to
   your instructor.)
2. Prepare a Context Data Model.
3. Prepare a Key-Based Data Model.
4. Prepare a Fully Attributed Data Model including any generalization hierarchies. Add the data
   attributes for each entity.
Your instructor will specify deliverable format and software to be used. Deliverables should be
neatly packaged in a binder, separated with a tab divider labeled ―Milestone 3.‖

References:

         Milestone 1 Solution
                Provided by your instructor.

         Milestone 2 Solution
                Provided by your instructor.

         Transcripts of Interviews with Tool Crib staff and Accompanying Sample Forms and
         Report
                Exhibit 1.1
                Exhibit 2.1
                Exhibits 3.1–3.4

         Templates
              See the online learning center website for the textbook.


Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed
System development for TCS - Milestone 3: Data Modeling                   Page 3-3

Deliverables:

         Entity Definition Matrix:                        Due: __/__/__
                                                          Time:_______

         Context Data Model:                              Due: __/__/__
                                                          Time:_______

         Key-Based Data Model:                            Due: __/__/__
                                                          Time:_______

         Fully Attributed Data Model:                     Due: __/__/__
                                                          Time:_______




Milestone’s Point Value:                                  _______




Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed
SADM 5/ed - CASE STUDY 2 TCS - Milestone 3: Data Modeling                                      Page: 3-4

The following is a copy of the transcripts of an interview between <your name> and Wilson
Hindman. The goal of this interview was to obtain sample forms used for processing tool check-ins
and check-outs and to be able to ask questions about them in order to discover data entities of the
business system.

Exhibit 3.1

Scene:     You have arranged to drop by the Tool                tool check-ins and check-outs that an
           Crib to pick up samples of forms used                employee did in the morning. Then, if
           to process tool check-ins and check-                 the same employee returned later in
           outs. Wilson Hindman was willing to                  the afternoon or at the end of the day
           collect them and answer any questions                to check in or out some tools, we
           that you might have.                                 would use a new form.
Wilson: Hi there <your name>! I assume you             You:     Just curious. Why wouldn’t you just
        are here to pick up the forms.                          pull the form when they come back in
                                                                and update it?
You:       Yes. Is this a good time? You said
           shortly after lunch.                        Wilson: Time! It takes time to look up the
                                                               form. We do file these, but sometimes
Wilson: Sure. Here are the forms. (see Exhibits                they don’t get filed right away. We
        3.2 – 3.4).                                            want to get the employees taken care
           Got any questions?                                  of as quickly as possible. So it is easier
                                                               to simply fill out a new one for each
You:       Let’s see . . . it appears that you use
                                                               visit.
           the same form to record a check-in and
           a check-out. Is this a form intended to     You:     What is this ―employee ID‖? Does the
           show a history for that employee?                    Physical Plant assign that?
Wilson: No, not at all. Each time an employee          Wilson: That is the Eudrup employee ID. We
        comes to the Tool Crib counter to                      simply use the university’s assigned
        conduct business with us, we pull one                  employee ID. I assume you noticed
        of these forms out and record all the                  that all our employees are wearing an
        check-in and check-out activity that                   employee ID badge that has their ID
        they wish to perform during that visit.                and photo. We started that two years
        It is not intended to be reused each                   ago. It makes things go more quickly.
        time they come back. I’m not sure why                  We don’t have to wait for them to pull
        we couldn’t use it that way, we just                   out their wallets and look up their ID.
        don’t.                                                 We can just read it.
You:       I see. So the ―date‖ refers to that day’s   You:     You mean they could not remember
           record of check-in and check-outs for                their social security number.
           the employee.                               Wilson: But you do realize that the Eudrup
Wilson: No, it is simply the date that they are                employee ID is not a person’s social
        conducting the tool check in or check                  security number.
        out. I know it is a little confusing. Let      You:     Ahhh, that is right. It’s a good thing
        me give you an example. We would                        too. Some people take issue with their
        use one of these forms to record all the

Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed
System Development for TCS - Milestone 3: Data Modeling                                       Page: 3-5

           right to privacy. You wouldn’t want                 just a simple vocabulary we use
           people to walk around with badges                   around here. Let me give you another
           displaying their social security                    example and this might clear things up
           number.                                             for you.
Wilson: That’s right. Anyhow, I suppose the                    Let’s say that an employee wants to
        rest of the form is self-explanatory                   check out a screwdriver. A
        isn’t it?                                              screwdriver is referred to as a small
                                                               tool. It is relatively inexpensive. Also,
You:       Do you have to record the ―tool ID‖
                                                               it is virtually impossible to track. A
           and the ―description‖?
                                                               particular screwdriver does not have a
Wilson: If it is a large tool we record the serial             serial number on it! But since it is
        number of the tool. Those are the tools                relatively inexpensive and virtually
        that we want to specifically track and                 impossible to track, we don’t even
        know who has that particular tool.                     attempt to do so. We simply want to
You:       Wait. I thought you wanted to track all             keep track of the fact that the
           tools. I am a little confused.                      employee checked out a screwdriver.
                                                               We don’t care which screwdriver. We
Wilson: We do. But see, there are certain tools                only care that we get the screwdriver
        that we want to track. For example,                    back.
        let’s say we have a particular air
        compressor and its serial number is           You:     Okay. I think I understand. Let’s see if
        123456789. That is an expensive item.                  I have this correct. You essentially are
        We want to track it. We want to know                   differentiating between tools. There
        that John Doe has checked out that                     are two types of tools, large tools and
        particular air compressor. We want to                  small tools. Large tools tend to be
        know where that particular air                         expensive and can and should be
        compressor is at all times.                            tracked. Small tools tend to be less
                                                               expensive and cannot be tracked.
You:       Okay, I understand that example. And
           you referred to it as a large tool.        Wilson: That is correct. So, for the large tools
                                                              we must enter the serial number for
Wilson: That is just a term we use to                         the tool. But, for the small tools we
        distinguish between tools that we                     enter a description of the tools.
        specifically want to track and other
        tools that we don’t necessarily want to       You:     I assume that the ―quantity in‖ and the
        track. Large tools are expensive and                   ―quantity out‖ for a large tool is
        small tools tend to be inexpensive.                    always one?
        Management feels that the large dollar        Wilson: That’s correct . . . in fact sometimes
        tools, or ―large tools‖ are killing us.               we don’t even enter a quantity, since it
        They really want us to keep track of                  can’t possibly be more than one.
        them. The small dollar tools, or small
                                                      You:     This zone leader form looks self-
        tools as we call them, are treated
                                                               explanatory (see Exhibit 3.3). And the
        differently.
                                                               employee registration looks pretty
           I realize this may be a little confusing            understandable. Except . . . what is
           to you. In reality, size of the tool has            the ―Foreman yes, no‖ portion of the
           nothing to do with our tracking. It’s               form?

Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed
System Development for TCS - Milestone 3: Data Modeling                                Page: 3-6

Wilson: We have to allow foremen to check                classification isn’t even entered on the
        out tools as well as their employees.            form.
        So we have to keep a record on them       You:   Okay. Thanks you for the forms and
        as well. Technically, foremen can                answering some my questions. Have a
        check out any tool, regardless of their          good day.
        classification. In fact, their




Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed
Systenm Development for TCS - Milestone 3: Data Modeling                      Page: 3-7

Exhibit 3.2




   Eudrup Tool Crib
   Eudrup University
   3303 Keady Blvd.
                                                         Check-Out/In
   Indianapolis, IN ZIP 47906
   317.494.3333 Fax 317.496.1212



EMPLOYEE ID:
                                                                 DATE:
NAME:




    TOOL ID                     Description   QTY OUT   QTY IN    Damage Description
    (serial #)                                                       (optional)




_____________________________________________________________________ __




Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed
Systenm Development for TCS - Milestone 3: Data Modeling          Page: 3-8

Exhibit 3.3



                                        EUDRUP TOOL CRIB
                                          ZONE LEADER

                                                   ZONE:
                                            *
                                                See map of zone


Foreman Name:              ________________________

Office:                    _____________________

Office Phone:              ______________

Special Notes:




Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed
Systenm Development for TCS - Milestone 3: Data Modeling                     Page: 3-9

Exhibit 3.4




                                      EUDRUP TOOL CRIB
                                    EMPLOYEE REGISTRATION




Employee ID:               _______________             Classification:



Customer Name:              ________________________   Zone:

Home Phone:                ______________              Foreman? • Yes • No

Emergency Phone:           ______________

Home Address:              _______________________

                           _______________________

                           _______________________



Special Notes:




Prepared by {Dr.M.A.Kashem} for
Systems Analysis & Design Methods 5ed

				
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