Chapter 4 : System Design - Coggle Diagram
Chapter 4 : System Design
4.1 Understand user interface design
Describes how users interact with a computer system
Evolution of the User Interface
Often, the user interface mainly consisted of process-control screens that allowed the user to send commands to the system.
Human-computer interaction (HCI) describes the relationship between computers and people who use them to perform their jobs
4.1.1.user interface design.
Principles of user-centered design
iii. Think Like a User
A systems analyst should understand user experience, knowledge, and skill levels.
iv. Use Models and Prototypes
From a user’s viewpoint, the interface is the most critical part of the system design because it is where he or she interacts with the system
ii. Maximize Graphical Effectiveness
Studies show that people learn better visually.
v. Focus on Usability
The user interface should include all tasks, commands, and communications between users and the information system.
i. Understand The Business
The interface designer must understand the underlying business functions and how the system supports individual, departmental, and enterprise goals.
vi. Invite Feedback
Even after the system is operational, it is important to monitor system usage and solicit user suggestions.
vii. Document Everything
You should document all screen designs for later use by programmers.
4.1.2 User Interface Design Guidelines
It is important to design a user interface that is easy to use, attractive, and efficient.
Good user interface design is based on a combination of:
how people work, learn, and interact with computers
how an interface can be made attractive and easy to use
operational structure required to carry out the design objectives
When you create a user interface, you should follow eight basic guidelines.
Enhance user productivity
Organize tasks, commands, and functions in groups that resemble actual business operations
Make it easy for users to obtain help or correct errors
Ensure that Help is always available
Create an interface that is easy to learn and use
Clearly label all controls, buttons, and icons
Minimize input data problems
-Create input masks.
-Display event-driven messages and reminders.
-Establish a list of predefined values that users can click to select.
-Build in rules that enforce data integrity.
Design a transparent interface
Facilitate the system design objectives, rather than calling attention to the interface
Provide feedback to users
Display messages at a logical place on the screen, and be consistent
Create an attractive layout and design
Use appropriate colors to highlight different areas of the screen
Use familiar terms and images
Remember that users are accustomed to a pattern of red=stop, yellow=caution, and green=go
4.1.4 Source Document
-collects input data
-triggers or authorizes an input action,
and provides a record of the original transaction
-paper-based, but also can be provided online
-developed during input design stage (that are easy to complete and use for data entry)
4.2 Input and Output Design
4.2.1 Input Design and Technology Issues
quality of the output = quality of the input
garbage in, garbage out (GIGO)
4.2.2 Objectives of Input Design
To ensure the quality, accuracy, and timeliness of
-Good input design requires attention to human factors as well as technology issues.
4.2.4 Data capture VS Data entry
Data capture - service in which data is captured via tick or check boxes and other items where areas are filled in with simple lines or shapes in order to get the right answer.
Data entry - manually entered text, copying exactly what the person who filled out the feedback form has written.
4.2.3 Guidelines For Data Entry Screen Design
Data Entry Screens (Guidelines)
1.Restrict user access to screen locations where data is entered
2.Provide a descriptive caption for every field, and show the user where to enter the data and the required or maximum field size
3.Display a sample format if a user must enter values in a field in a specific format - separator
4.Require an ending keystroke for every field
5.Do not require users to type leading zeroes for numeric fields
6.Do not require users to type trailing zeroes for numbers that include decimals
7.Display default values so operators can press the ENTER key to accept the suggested value
8.Use a default value when a field value will be constant for successive records or throughout the data entry session
9.Display a list of acceptable values for fields, and provide meaningful error messages
10.Provide a way to leave the data entry screen at any time without entering the current record
11.Provide users with an opportunity to confirm the accuracy of input data before entering it
12.Provide a means for users to move among fields on the form
13.Design the screen form layout to match the layout of the source document
14.Allow users to add, change, delete, and view records
15.Provide a method to allow users to search for specific information
4.2.5 Input & Data Entry Method
Input technology has changed dramatically in recent years.
In addition to traditional devices and methods, there has been a rapid expansion of new hardware and ways to capture and enter data into a system
a. Batch Input
data entry is performed on a specified time schedule [ daily, weekly, monthly, or longer ]
b. Online Input
batch input - used in specific situations
but most business activity requires online data entry
-availability of data
4.2.6 Input Mask & Validation Rules
type of data validation rules
used for mandatory data items
Data type check
tests to ensure that a data item fits the required data type
used when the data must be in some predetermined sequence
tests data items to verify that they fall between a specified minimum and maximum value.
identifies values that are questionable, but not necessarily wrong
used for data items that must have certain values
Another type of validity check:
referential integrity - value entered must refer to another value
example : verify that a new customer number does not match a number already stored in the customer master file
example : verifying that a customer number on an order matches a customer number in the customer file
performed on 2 or more fields to ensure that they are consistent or reasonable when considered together
totals used to verify batch input
might check data items such as record counts and numeric field totals
4.2.8 Output Technology
Although business information systems still provide most output as screen displays and printed matter, technology is having an enormous impact on how people communicate and obtain information.
Besides printed report, system also should consider various types of output technologies;
Internet based information delivery
Millions of firms use the Internet to reach new customers and markets around the world.
Specialized forms of output
An incredibly diverse marketplace requires many forms of specialized output and devices
4.2.9 Types Of Reports
a report must include the information that a user needs
from a user’s point of view:
-too little information = no value
-too much information = confusing and difficult to understand
produces one or more lines of output for each record processed
displays only those records that meet a specific condition or conditions
Upper-level managers often want to see total figures and do not need supporting details
4.2.10 Design Report Principles
must be attractive, professional, and easy to read.
Report headers and footers
-Every report should have a report header and a report footer.
-The report header, which appears at the beginning of the report, identifies the report, and contains the report title, date, and other necessary information.
Column heading alignment
EX1 - Column headings are left-justified over maximum field widths
EX2 - Column headings are right-justified over maximum field widths
EX3 - Column headings are centered over maximum field widths
EX4 - Column headings are left-justified over alphanumeric fields and right-justified over numeric fields.
You should space columns of information carefully.
A crowded report is hard to read, and large gaps between columns make it difficult for the eye to follow a line.
Fields should be displayed and grouped in a logical order.
Grouping detail lines
Often, it is meaningful to arrange detail lines in groups, based on a control field.
Report design is an art, not a science.
Look and feel are important to users, so reports should be uniform and consistent.
4.2.12 Input & Output Controls & Security
A company must do everything in its power to protect its data.
Output control & security
Output security protects privacy rights and shields the organization’s proprietary data from theft or unauthorized access.
Input control & security
Input control includes the necessary measures to ensure that input data is correct, complete, and secure.
4.1.3 User Interface Components
Screen Elements & Controls
-List box – scroll bar
-Drop-down list box
-Option button, or radio button