Computer Science Assignment - Level 0 data flow Diagram and Create a Data Structure

Question 1 - . Consider the following (simplified) desired functionality for a system to check out books from a library.

The patron presents the library book which has an inventory barcode sticker. Also, they provide their library card Whichalso has a barcode. The desk clerk scans the card to see if the patron has any overdue Items or fines due. If the accumulated fines are above a certain level, the patron cannot check out a book unless they pay their fines and return the overdue books.

If the patron pays the fines for the overdue book, they can have its checkout period extended unless there is a "hold" onthe book. A hold means that another patron has requested the book to be held for them when it is retumed.

Once the ability to check out books is established, the desk clerk scans the barcode on the book and generates a checkout record for the patron.

A regular activity report is given to management so they can evaluate the service the library is providing to the community ..

A context diagram for the system is shown below.

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Delinquency Record

Book Info a

Management

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, "...•. ._-----------~ " Checkout Record "'"

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Hold C~rtftrmation

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Checkout Patron ,_p-ayrnent-o:; Patron Jnfo~

Library Checkout

System

Hold Patron

~ O",w a level 0 data flow dlag",m 1m this system. 6-,.. <L r ~;u f ;}"-'- US;: Vi5 iv) Question 2 - For the Context Diagram above, develop a data structure for each of the data flows, similar to that found on Figure 8.14 in your textbook.

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FIGURE 8.14

USING THE DATA DICTIONARY

The ideal data dictiona'ry is automated, interactive, online, and evolutionary. As the systems ana- lyst learns about the organization's systems, data items are added to the data dictionary. On the

other hand, the data dictionary is not an end in itself and must nev<?rbecome so. To avoid becom- ing sidetracked with the building of a complete data dictionary, the systems analyst should view it as an activity that parallels systems analysis and design.

To have maximum power, the data dictionary should be tied into a number of systems pro- grams so that when an item is updated or deleted from the data dictionary, it is automatically up- dated or deleted from the database. The data dictionary becomes simply a historical curiosity if it is not kept current.

The data dictionary may be used to create screens, reports, and forms. For example, exam- ine the data structure for the World's Trend ORDER PICKING SLIP in Figure 8.14. Because the

necessary elements and their lengths have been defined, the process of creating physical docu- ments consists of arranging the elements in a pleasing and functional way using design guidelines and common sense. Repeating groups become columns, and structural records are grouped to- gether on the screen, report, or form. The report layout for the World's Trend ORDER PICKING

SLIP is shown in Figure 8.1 S. Notice that FIRST NAME and LAST NAME are gr<?uped together

Data structure for an order picking slip at World's Trend Catalog Division.

Order Picking Slip =0 Order Number +

Order Date +

Customer Number +

Customer Name + .

Customer Address +

Customer Telephone +.

/Order Item Selectionl + Number of Items

Order Item Selection =0

Customer Name = 'I

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Address =0

Telephone =0

Item Number +

Item Description +

Size Description +

Color Description +

Warehouse Section +

Shelf Number +

Quantity Ordered +

Quantity Picked

First Name +

(Middle Initial) + last Name

Street +

(Apartment) + City +

State +

Zip +

(lip Expansion) + (Country)

Area Code +

local Number