Systems Analysis and Design 11th Edition Chapter 8 User Interface Design PDF
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This document is a chapter from a textbook on systems analysis and design, focusing on user interface design. The chapter includes several topics, such as human-computer interaction, design rules, and input/output technology issues.
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Chapter 8 User Interface Design Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 1 duplicated, or posted to a publicly accessible website, in whole or in part. Explain the concept of user interface design and human-computer interaction, including...
Chapter 8 User Interface Design Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 1 duplicated, or posted to a publicly accessible website, in whole or in part. Explain the concept of user interface design and human-computer interaction, including basic principles of user-centered design Explain how experienced interface designers perform their tasks Describe rules for successful interface design Discuss input and output technology issues Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 2 duplicated, or posted to a publicly accessible website, in whole or in part. Design effective source documents and forms Explain printed output guidelines Describe output and input controls and security Explain modular design and prototyping techniques Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 3 duplicated, or posted to a publicly accessible website, in whole or in part. Goal of systems design - To build a system that is effective, reliable, and maintainable ◦ A system is: Effective if it supports business requirements and meets user needs Reliable if it handles input errors, processing errors, hardware failures, or human mistakes Maintainable if it is flexible, scalable, and easily modified Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 4 duplicated, or posted to a publicly accessible website, in whole or in part. Will It Succeed? ◦ Suggestions for successful design Think like a user Carefully examine any point where users provide input or receive output Anticipate future needs and provide flexibility Anticipate possible expansion Offer several alternatives Manage data effectively System should enter and verify data as soon as possible Input data must be close to its source A secure system must include audit trails Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 5 duplicated, or posted to a publicly accessible website, in whole or in part. Users can design their own output ◦ System designers are more aware of user needs and desires Centralized IT departments no longer produce reams of printed reports ◦ Customer-designed output is the current trend The user interface has evolved ◦ Most user information needs can be met with screen-generated data ◦ Continues to evolve with the use of mobile and wearable devices Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 6 duplicated, or posted to a publicly accessible website, in whole or in part. Describes how users interact with a computer system ◦ Comprises features that affect two-way communications between the user and the computer Central to usability ◦ In a user-centered system, the distinction blurs between input, output, and the interface itself FIGURE 8-2 Apple has long been a leader in creating elegant user interfaces for its products. Source: Apple Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 7 duplicated, or posted to a publicly accessible website, in whole or in part. Human-Computer Interaction (HCI) ◦ Describes the relationship between computers and people who use them to perform their jobs ◦ Early user interfaces – Complex commands and graphical user interface (GUI) ◦ Transparent user interface: Does not distract the user ◦ Objective - To create a user-friendly design that is easy to learn and use Figure 8-3 HCI is essential to employee productivity, whether the work is done in a traditional office setting or on a construction site like the one shown in this figure. Goodluz/Shutterstock.com Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 8 duplicated, or posted to a publicly accessible website, in whole or in part. Understand the Business ◦ The interface designer must understand: The underlying business functions How the system supports individual, departmental, and enterprise goals Maximize Graphical Effectiveness ◦ A well-designed interface enables rapid learning Think Like a User ◦ The designer must see the system from a user’s perspective Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 9 duplicated, or posted to a publicly accessible website, in whole or in part. Use Models and Prototypes ◦ Designers can present initial screen designs to users in the form of a storyboard Users should test the design and provide feedback Focus on Usability ◦ Include main options in the opening screen ◦ Offer a reasonable number of choices that a user easily can comprehend FIGURE 8-5 The opening screen displays the main options for a student registration system. A user can click an option to see lower-level actions and menu choices. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 10 duplicated, or posted to a publicly accessible website, in whole or in part. Invite Feedback ◦ Monitor system usage and solicit user suggestions ◦ Determine if system features are being used as intended by observing and surveying users Document Everything ◦ Document all screen designs for later use by programmers ◦ User-approved sketches and storyboards can be used to document the user interface Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 11 duplicated, or posted to a publicly accessible website, in whole or in part. Create an Interface That Is Easy to Learn and Use ◦ Focus on system design objectives ◦ Create a design that is easy to understand and remember ◦ Provide commands, actions, and system responses that are consistent and predictable ◦ Allow users to correct errors easily ◦ Clearly label all controls, buttons, and icons Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 12 duplicated, or posted to a publicly accessible website, in whole or in part. Create an Interface That Is Easy to Learn and Use (Cont.) ◦ Select familiar images that users can understand Provide on-screen instructions that are logical, concise, and clear ◦ Show all commands in a list of menu items Dim any commands that are not available to the user ◦ Make it easy to navigate or return to any level in the menu structure Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 13 duplicated, or posted to a publicly accessible website, in whole or in part. Enhance User Productivity ◦ Organize tasks, commands, and functions in groups that resemble actual business operations ◦ Create alphabetical menu lists or place the selections used frequently at the top of the menu list ◦ Provide shortcuts for experienced users ◦ Use default values if the majority of values in a field are the same ◦ Use a duplicate value function, but allow users to turn this feature on or off as they prefer Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 14 duplicated, or posted to a publicly accessible website, in whole or in part. Enhance User Productivity (Cont.) ◦ Provide a fast-find feature ◦ If available, consider a natural language feature that allows users to type commands or requests in normal text phrases Provide Users with Help and Feedback ◦ Ensure that help is always available on demand ◦ Provide user-selected help and context- sensitive help ◦ Provide a direct route for users to return to the point from where help was requested ◦ Include contact information Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 15 duplicated, or posted to a publicly accessible website, in whole or in part. Provide Users with Help and Feedback (Cont.) ◦ Require user confirmation before data deletion ◦ Provide an “Undo” key ◦ When a user-entered command contains an error, highlight the erroneous part ◦ Use hypertext links to assist users ◦ Display messages at a logical place on the screen ◦ Alert users to lengthy processing times or delays ◦ Allow messages to remain on the screen long enough for users to read them ◦ Let the user know whether the task or operation was successful or not Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 16 duplicated, or posted to a publicly accessible website, in whole or in part. Figure 8-7 This menu hierarchy shows tasks, commands, and functions organized into logical groups and sequences. The structure resembles a functional decomposition diagram (FDD), which is a model of business functions and processes. Figure 8-8 The main Help screen for a student registration system. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 17 duplicated, or posted to a publicly accessible website, in whole or in part. Provide Users with Help and Feedback (Cont.) ◦ Provide a text explanation for an icon or image on a control button ◦ Use messages that are specific, understandable, and professional Create an Attractive Layout and Design ◦ Use appropriate colors to highlight different areas of the screen ◦ Use special effects sparingly ◦ Use hyperlinks that allow users to navigate to related topics ◦ Group related objects and information Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 18 duplicated, or posted to a publicly accessible website, in whole or in part. Create an Attractive Layout and Design (Cont.) ◦ Display titles, messages, and instructions in a consistent manner ◦ Ensure that commands and similar mouse actions will have the same effect ◦ Require the user to confirm the entry by pressing Enter or Tab ◦ Remember that users are accustomed to a pattern of red = stop, yellow = caution, and green = go ◦ Provide a keystroke alternative for each menu command ◦ Avoid complex terms and technical jargon Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 19 duplicated, or posted to a publicly accessible website, in whole or in part. Enhance the Interface ◦ Opening screen is important as it introduces the application The starting point can be a switchboard with well- placed command buttons for navigation ◦ Use a command button to initiate an action ◦ Try to create customized menu bars and toolbars ◦ Add a shortcut feature that lets a user select a menu command ◦ If variable input data is needed, provide a dialog box that explains what is required Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 20 duplicated, or posted to a publicly accessible website, in whole or in part. Enhance the Interface (Cont.) ◦ A toggle button makes it easy to show on or off status ◦ Use list boxes that display the available choices ◦ Use an option button, or a radio button, to control user choices ◦ If check boxes are used to select one or more choices from a group, show the choices with a checkmark or an X ◦ When dates must be entered, use a calendar control Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 21 duplicated, or posted to a publicly accessible website, in whole or in part. FIGURE 8-10 A data entry screen for the student registration system. This screen uses several design features that are described in the text. When a user clicks the Find Student command button, a dialog box is displayed with instructions. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 22 duplicated, or posted to a publicly accessible website, in whole or in part. Focus on Data Entry Screens ◦ Use the form filling method whenever possible ◦ Restrict user access to screen locations where data is entered ◦ Provide a way to leave the data entry screen at any time without entering the current record ◦ Provide a descriptive caption for every field ◦ Provide a means for users to move among fields on the form in a standard order or in any order they choose ◦ Allow users to add, change, delete, and view records Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 23 duplicated, or posted to a publicly accessible website, in whole or in part. Focus on Data Entry Screens (Cont.) ◦ Design the screen form layout to match the layout of the source document ◦ Display a sample format like MMDDYY and use an input mask ◦ Require an ending stroke for every field ◦ Do not require users to type leading zeros for numeric fields or trailing zeros for decimals ◦ Display default values ◦ Provide users with an opportunity to confirm the accuracy of input data before displaying it Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 24 duplicated, or posted to a publicly accessible website, in whole or in part. FIGURE 8-12 Microsoft Access provides various input masks for dates, phone numbers, and postal codes, among others. In addition, it is easy to create a custom mask using the characters shown here. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 25 duplicated, or posted to a publicly accessible website, in whole or in part. Focus on Data Entry Screens (Cont.) ◦ Use a default value when a field value will be constant for successive records or throughout the data entry session Use Validation Rules ◦ Sequence check: Used when the data must be in some predetermined sequence ◦ Existence check: Applies to mandatory data items ◦ Data type check: Tests to ensure that a data item fits the required data type ◦ Range check: Used to verify that data items fall between a specified minimum and maximum value Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 26 duplicated, or posted to a publicly accessible website, in whole or in part. Use Validation Rules (Cont.) ◦ Reasonableness check: Identifies values that are questionable, but not necessarily wrong ◦ Validity check: Used for data items that must have certain values ◦ Combination check: Performed on two or more fields to ensure that they are consistent or reasonable when considered together ◦ Batch controls: Totals used to verify batch input Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 27 duplicated, or posted to a publicly accessible website, in whole or in part. FIGURE 8-13 Microsoft Access provides validation rules can improve data quality by requiring the input to meet specific requirements or conditions. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 28 duplicated, or posted to a publicly accessible website, in whole or in part. Reduce Input Volume ◦ Input necessary data only ◦ Do not input data that the user can retrieve from system files or calculate from other data ◦ Do not input constant data ◦ Use codes as they are shorter than the data they represent Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 29 duplicated, or posted to a publicly accessible website, in whole or in part. Garbage in, garbage out (GIGO): Quality of the output depends on the quality of the input Source document: Collects input data, triggers an input action, and provides a record of the original transaction A good form layout makes the form easy to complete and provides enough space ◦ Information should flow on a form from left to right and top to bottom Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 30 duplicated, or posted to a publicly accessible website, in whole or in part. Order and placement of printed fields should be logical Totals should be identified clearly FIGURE 8-14 Source document zones. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 31 duplicated, or posted to a publicly accessible website, in whole or in part. Questions to be considered before designing printed output ◦ Why is this being delivered as printed output? ◦ Who wants the information, why is it needed, and how will it be used? ◦ What specific information will be included? ◦ Will the printed output be designed for a specific device? ◦ Do security or confidentiality issues exist? Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 32 duplicated, or posted to a publicly accessible website, in whole or in part. Overview of Report Design ◦ Organizations strive to reduce the flow of paper and printed reports Users find it handy to view screen output, then print the information they need ◦ Printed output is used in turnaround documents ◦ Reports must be easy to read and well organized Database programs such as Microsoft Access include a variety of report design tools to create reports quickly and easily Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 33 duplicated, or posted to a publicly accessible website, in whole or in part. Types of Reports ◦ Detail reports: Produce one or more lines of output for each record processed Can be quite lengthy ◦ Exception reports: Display only those records that meet specific conditions Useful when the user wants specific information ◦ Summary reports: Reports that provide comprehensive data Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 34 duplicated, or posted to a publicly accessible website, in whole or in part. User Involvement ◦ Users must approve all report designs in advance A mock-up, or prototype, can be prepared for the users to review Report Design Principles ◦ Every report should have a report header and footer Report header: Identifies the report, and contains the report title, date, and other necessary information Report footer: Contains end-of-report information Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 35 duplicated, or posted to a publicly accessible website, in whole or in part. Report Design Principles (Cont.) ◦ Page headers and footers Page header: Includes the column headings that identify the data Page footer: Displays the report title and the page number ◦ Repeating fields Users’ opinion helps provide clarity ◦ Consistent design Look and feel are important to users, so reports should be uniform and consistent Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 36 duplicated, or posted to a publicly accessible website, in whole or in part. FIGURE 8-15 The Employee Hours report is a detail report with control breaks, subtotals, and grand totals. Notice that a report header identifies the report, a page header contains column headings, a group footer contains subtotals for each store, a report footer contains grand totals, and a page footer identifies the page number. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 37 duplicated, or posted to a publicly accessible website, in whole or in part. Output Technology ◦ In addition to screen output and printed matter, output can be delivered in many ways ◦ Actual forms, reports, and documents have to be created to be accessible from workstations, notebooks, tablets, smartphones, and other devices ◦ Internet-based information delivery Allows users to download a universe of files and documents to support their information needs Companies use a live or prerecorded webcast to reach prospective customers and investors Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 38 duplicated, or posted to a publicly accessible website, in whole or in part. Output Technology (Cont.) ◦ Email - An essential means of internal and external business communication ◦ Blogs: Web based logs Useful for posting news, reviewing current events, and promoting products ◦ Instant messaging - Useful for team members in a collaborative situation ◦ Wireless devices - Data can be transmitted using the Internet across a wide array of devices Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 39 duplicated, or posted to a publicly accessible website, in whole or in part. Output Technology (Cont.) ◦ Digital audio, images and video Can be captured and stored in digital format Can be attached to an email message or inserted as a clip in a Microsoft Word document ◦ Podcasts Used as sales and marketing tools, and to communicate with the employees ◦ Automated fax or faxback systems Allow a customer to request a fax using e-mail, via the company Web site, or by telephone Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 40 duplicated, or posted to a publicly accessible website, in whole or in part. Output Technology (Cont.) ◦ Computer output to microfilm (COM) Used by large firms to scan and store images of original documents to provide high-quality records management and archiving ◦ Computer output to digital media Used when many paper documents must be scanned and stored in digital format for quick retrieval Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 41 duplicated, or posted to a publicly accessible website, in whole or in part. Output Technology (Cont.) ◦ Specialized forms of output Portable, Web-connected devices that can run multiple apps Retail point-of-sale terminals that handle credit card transactions Automatic teller machines (ATMs) that can process bank transactions Special-purpose printers Plotters that can produce high-quality images Electronic detection of data embedded in credit cards, bank cards, and employee identification cards Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 42 duplicated, or posted to a publicly accessible website, in whole or in part. FIGURE 8-17 Input devices can be very traditional, or based on the latest technology. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 43 duplicated, or posted to a publicly accessible website, in whole or in part. Input Technology ◦ Batch input: Data entry is performed on a specified time schedule, such as daily, weekly, monthly, or longer ◦ Online data entry Enables immediate validation and availability of data Source data automation combines online data entry and automated data capture using input devices such as RFID tags, magnetic data strips, or smartphones Fast and accurate, and minimizes human involvement in the translation process Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 44 duplicated, or posted to a publicly accessible website, in whole or in part. Input Technology (Cont.) Examples of source data automation Point-of-sale (POS) terminals equipped with bar code scanners and magnetic swipe scanners Automatic teller machines (ATMs) read data strips on bank cards Factory employees use magnetic ID cards to clock on and off specific jobs Hospitals imprint bar codes on patient identification bracelets and use portable scanners when gathering data on patient treatment and medication Retail stores use portable bar code scanners and libraries use handheld scanners Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 45 duplicated, or posted to a publicly accessible website, in whole or in part. Input Technology (Cont.) ◦ Trade offs Manual data entry is slower and more expensive than batch input Performed at the time the transaction occurs Often done when computer demand is at its highest Decision to use batch or online input depends on business requirements Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 46 duplicated, or posted to a publicly accessible website, in whole or in part. Output Security and Control ◦ Companies use output control methods to maintain output integrity and security ◦ Output security protects privacy rights Shields the organization’s proprietary data from theft or unauthorized access ◦ Security solutions Diskless workstation: Network terminal that supports a full-featured user interface but limits the printing or copying of data Port protector: Controls access to and from workstation interfaces Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 47 duplicated, or posted to a publicly accessible website, in whole or in part. Input Security and Control ◦ Input control ensures that the input data is correct, complete, and secure Information should be traceable back to the input data that produced it Procedures must be put in place for handling source documents to ensure that data is not lost before it enters the system ◦ Data security policies and procedures protect data from loss or damage Companies should have a records retention policy that meets all legal requirements and business needs Audit trail files and reports should be stored and saved Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 48 duplicated, or posted to a publicly accessible website, in whole or in part. Modular Design ◦ Individual components, called modules, connect to a higher-level program or process Designed to perform a single function ◦ In a structured design, each module represents a specific process Shown on a data flow diagram (DFD) and documented in a process description Prototyping ◦ Involves a repetitive sequence of analysis, design, modeling, and testing Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 49 duplicated, or posted to a publicly accessible website, in whole or in part. Prototyping (Cont.) ◦ System prototyping Produces a full-featured, working model of the information system ◦ Design or throwaway prototyping Used to verify user requirements and is discarded FIGURE 8-21 The end product of system prototyping is a working model of the information system, ready for implementation. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 50 duplicated, or posted to a publicly accessible website, in whole or in part. Prototyping (Cont.) ◦ Benefits Users and systems developers can avoid misunderstandings System developers can create accurate specifications for the finished system based on the prototype Managers can evaluate a working model more effectively than a paper specification Helps in developing testing and training procedures Reduces the risk and potential financial exposure that occur when a finished system fails to support business needs Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 51 duplicated, or posted to a publicly accessible website, in whole or in part. Prototyping (Cont.) ◦ Potential problems Rapid pace of development can create quality problems which may not be discovered until the finished system is operational System requirements, such as reliability and maintainability, cannot be tested adequately using a prototype In complex systems, the prototype can become unwieldy and difficult to manage Clients may want to adopt the prototype with few to no changes, leading to increased maintenance costs later in the SDLC Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 52 duplicated, or posted to a publicly accessible website, in whole or in part. Purpose of systems design ◦ To create a physical model of the system that satisfies the design requirements that were defined during the systems analysis phase User interface design must be based on the perspective of the user Types of printed reports ◦ Detail, exception, and summary reports Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 53 duplicated, or posted to a publicly accessible website, in whole or in part. Various zones in a document ◦ Heading zone, control zone, instruction zone, body zone, totals zone, and authorization zone Input methods include data capture and data entry Security and control plays an important role in designing Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or 54 duplicated, or posted to a publicly accessible website, in whole or in part. Chapter 9 – Data Design Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. Explain file-oriented systems and how they differ from database management systems Explain data design terminology, including entities, fields, common fields, records, files, tables, and key fields Describe data relationships, draw an entity- relationship diagram, define cardinality, and use cardinality notation Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 2 Explain the concept of normalization Explain the importance of codes and describe various coding schemes Explain data warehousing and data mining Differentiate between logical and physical storage and records Explain data control measures Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 3 Data Structures ◦ Framework for organizing, storing, and managing data ◦ Comprises of files or tables that interact in various ways Each file or table contains data about people, places, things, or events Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 4 Mario and Danica - A Data Design Example ◦ Mario’s auto shop uses file-oriented systems MECHANIC SYSTEM uses the MECHANIC file to store data about shop employees JOB SYSTEM uses the JOB file to store data about work performed at the shop ◦ Danica’s auto shop uses a relational model SHOP OPERATIONS SYSTEM - Tables are linked by a common field named Mechanic No field Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 5 Mario’s Auto Shop Danica’s Auto Shop FIGURE 9-4 Danica’s SHOP OPERATIONS SYSTEM uses a database design, which avoids duplication. The data can be viewed as if it were one large table, regardless of where the data is stored physically. FIGURE 9-2 Mario’s shop uses two separate systems, so certain data must be entered twice. This redundancy is inefficient and can produce data errors. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 6 Is File Processing Still Important? ◦ Used by some companies to handle large volumes of structured data on a regular basis Cost-effective in certain situations FIGURE 9-4 A credit card company that posts thousands of daily transactions might consider a file processing option. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 7 The Database Environment ◦ Database management system (DBMS): Collection of tools, features, and interfaces that enables users to add, update, manage, access, and analyze data ◦ DBMS advantages Scalability - System can be expanded, modified, or downsized Economy of scale Database design allows better utilization of hardware Figure 9-5 In this example, a sales database can support four separate business systems. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 8 Enterprise-wide application A database administrator (DBA) assesses overall requirements and maintains the database Stronger standards Standards for data names, formats, and documentation are followed uniformly throughout the organization Better security Only legitimate users can access the database Different users have different levels of access Data independence Systems that interact with a DBMS are relatively independent of how physical data is maintained Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 9 Interfaces for Users, Database Administrators, and Related Systems ◦ Users Work with predefined queries and switchboard commands Use query languages to access stored data ◦ Database administrators Responsible for DBMS management and support FIGURE 9-6 In addition to interfaces ◦ Related information systems or users, database administrators, and related information systems, a DBMS provides support to DBMS also has a data manipulation related information systems language, a schema and subschemas, and a physical data repository. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 10 Data Manipulation Language (DML) ◦ Controls database operations Schema ◦ Descriptions of all fields, tables, and relationships Subschema: Portions of the database that a particular system or user needs or is allowed to access Physical Data Repository ◦ Contains the schema and subschemas ◦ Can be centralized or distributed at several locations ◦ Uses open database connectivity (ODBC)-compliant software that enables communication among the systems and DBMSs Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 11 Connecting to the Web ◦ Databases are created and managed by using languages and commands that have nothing to do with HTML Objective - To connect the database to the Web and enable data to be viewed and updated Middleware is used integrate different applications and allow them to exchange data Data Security ◦ Web-based data must be secure, yet easily accessible to authorized users Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 12 FIGURE 9-8 A Web-based design characteristics include global access, ease of use, multiple platforms, cost effectiveness, security issues, and adaptability issues. In a Web-based design, the Internet serves as the front end, or interface, for the database management system. Access to the database requires only a Web browser and an Internet connection. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 13 FIGURE 9-9 When a client workstation requests a Web page (1), the Web server uses middleware to generate a data query to the database server (2). The database server responds (3), and middleware translates the retrieved data into an HTML page that can be sent by the Web server and displayed by the user’s browser (4). Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 14 Definitions ◦ Entity - Person, place, thing, or event for which data is collected and maintained ◦ Table or file: Contains a set of related records that store data about a specific entity ◦ Field (attribute) - Single characteristic or fact about an entity Common field: Attribute that appears in more than one entity ◦ Tuple (record): Set of related fields that describes one instance, or occurrence, of an entity Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 15 Key Fields ◦ Primary key: Field or combination of fields that uniquely and minimally identifies a particular member of an entity Called a combination key ◦ Candidate key: Any field that could serve as a primary key ◦ Foreign key: Field in one table that must match a primary key value in another table for a relationship between the two tables to exist ◦ Secondary key: Field or combination of fields that can be used to access or retrieve records Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16 Referential Integrity ◦ Set of rules that avoids data inconsistency and quality problems FIGURE 9-11 Microsoft Access allows a user to specify that referential integrity rules will be enforced in a relational database design. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 17 Drawing an ERD ◦ List the entities that were identified during the systems analysis phase Consider the nature of the relationships that link them FIGURE 9-12 In an entity-relationship diagram, entities are labeled with singular nouns and relationships are labeled with verbs. The relationship is interpreted as a simple English sentence. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 18 Types of Relationships ◦ One-to-one relationship: Exists when exactly one of the second entity occurs for each instance of the first entity Abbreviated 1:1 FIGURE 9-13 Examples of one-to-one (1:1) relationships. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 19 ◦ One-to-many relationship: Exists when one occurrence of the first entity can relate to many instances of the second entity Each instance of the second entity can associate with only one instance of the first entity Abbreviated 1:M FIGURE 9-14 Examples of one-to-many (1:M) relationships. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 20 ◦ Many-to-many relationship Exists when one instance of the first entity can relate to many instances of the second entity, and vice versa Abbreviated M:N FIGURE 9-15 Examples of many-to-many (M:N) relationships. Notice that the event or transaction that links the two entities is an associative entity with its own set of attributes and characteristics Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 21 FIGURE 9-16 An entity-relationship diagram for SALES REP, CUSTOMER, ORDER, PRODUCT, and WAREHOUSE. Notice that the ORDER and PRODUCT entities are joined by an associative entity named ORDER LINE. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 22 Cardinality ◦ Describes the numeric relationship between two entities ◦ Shows how instances of one entity relate to instances of another entity ◦ Crow’s foot notation indicates various possibilities using circles, FIGURE 9-17 Crow’s foot notation is a common bars, and symbols method of indicating cardinality. The four examples show how you can use various symbols to describe the relationships between entities. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 23 FIGURE 9-18 In the first example of cardinality notation, one and only one CUSTOMER can place anywhere from zero to many of the ORDER entity. In the second example, one and only one ORDER can include one ITEM ORDERED or many. In the third example, one and only one EMPLOYEE can have one SPOUSE or none. In the fourth example, one EMPLOYEE, or many employees, or none, can be assigned to one PROJECT, or many projects, or none. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 24 FIGURE 9-19 An ERD for a library system drawn with Visible Analyst. Notice that crow’s foot notation has been used and relationships are described in both directions. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 25 Normalization: Process of creating table designs by assigning specific fields or attributes to each table in the database Table design: Specifies fields ◦ Identifies the primary key in a particular table or file Stages in a normalization process ◦ Unnormalized design ◦ First normal form ◦ Second normal form ◦ Third normal form Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 26 Standard Notation Format ◦ Used to show a table’s structure, fields, and primary key ◦ The primary key field(s) is underlined NAME (FIELD 1, FIELD 2, FIELD 3) ◦ Recognition of repeating group fields is important Repeating group: Set of one or more fields that can occur any number of times in a single record Each occurrence would possess different values Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 27 FIGURE 9-20 In the ORDER table design, two orders have repeating groups that contain several products. ORDER is the primary key for the ORDER table, and PRODUCT NUMBER serves as a primary key for the repeating group. Because it contains repeating groups, the ORDER table is unnormalized. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 28 First Normal Form (1NF) ◦ Does not contain a repeating group ◦ Converting an unnormalized design to 1NF requires expansion of the table’s primary key to include the primary key of the repeating group Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 29 FIGURE 9-21 The ORDER table as it appears in 1NF. The repeating groups have been eliminated. Notice that the repeating group for order 86223 has become three separate records, and the repeating group for order 86390 has become two separate records. The 1NF primary key is a combination of ORDER and PRODUCT NUMBER, which uniquely identifies each record. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 30 Second Normal Form (2NF) ◦ Examples of functional dependence Field A is functionally dependent on Field B if the value of Field A depends on Field B A table design is in 2NF if: It is in 1NF All fields not part of the primary key are functionally dependent on the entire primary key Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 31 FIGURE 9-22 ORDER, PRODUCT, and ORDER LINE tables in 2NF. All fields are functionally dependent on the primary key. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 32 Third Normal Form (3NF) ◦ A design is in 3NF if it is in 2NF and if no nonkey field is dependent on another nonkey field ◦ Avoids redundancy and data integrity problems that still can exist in 2NF designs Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 33 FIGURE 9-23 When the PRODUCT table is transformed from 2NF to 3F, the result is two separate tables: PRODUCT and SUPPLIER. Note that in 3NF, all fields depend on the key, the whole key, and nothing but the key! Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 34 Crossroads College FIGURE 9-25 An initial entity-relationship diagram for ADVISOR, STUDENT, and COURSE. FIGURE 9-26 The STUDENT table is unnormalized because it contains a repeating group that represents the courses each student has taken. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 35 FIGURE 9-27 The STUDENT table in 1NF. Notice that the primary key has been expanded to include STUDENT NUMBER and COURSE NUMBER. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 36 FIGURE 9-28 The STUDENT, COURSE, and GRADE tables in 2NF. Notice that all fields are functionally dependent on the entire primary key of their respective tables. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 37 FIGURE 9-29 STUDENT, ADVISOR, COURSE, and GRADE tables in 3NF. When the STUDENT table is transformed from 2NF to 3NF, the result is two tables: STUDENT and ADVISOR. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 38 FIGURE 9-30 The entity-relationship diagram for STUDENT, ADVISOR, and COURSE after normalization. The GRADE entity was identified during the normalization process. GRADE is an associative entity that links the STUDENT and COURSE tables. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 39 Example 2: Magic Maintenance FIGURE 9-31 A relational database design for a computer service company uses common fields to link the tables and form an overall data structure. Notice the one-to-many notation symbols, and the primary keys, which are indicated with gold- colored key symbols. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 40 FIGURE 9-32 Sample data, primary keys, and common fields for the database shown in Figure 9-31. The design is in 3NF. Notice that all nonkey fields functionally depend on a primary key, the whole primary key, and nothing but the primary key. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 41 Overview of Codes ◦ Codes are shorter than the data they represent Save storage space and costs Decrease data entry time and transmission time ◦ Codes can: Reveal or conceal information Reduce data input errors ◦ Coded data is easier to remember Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 42 Types of Codes ◦ Sequence codes: Numbers or letters assigned in a specific order Contain no additional information other than an indication of order of entry into the system ◦ Block sequence codes: Use blocks of numbers for different classifications Sequence of numbers in a particular block can have additional meaning ◦ Significant digit codes: Distinguish items by using a series of subgroups of digits Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 43 ◦ Alphabetic codes: Use letters to distinguish one item from another Category codes: Identify a group of related items Abbreviation codes: Alphabetic abbreviations Mnemonic codes: Use specific combination of letters that are easy to remember ◦ Derivation codes: Combine data from different item attributes, or characteristics ◦ Cipher codes: Use a keyword to encode a number ◦ Action codes: Indicate what action is to be taken with an associated item Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 44 FIGURE 9-34 Abbreviations for some of the world’s busiest airports. BLANKartist/Shutterstock.com Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 45 FIGURE 9-35 Sample of a code that uses significant digits to pinpoint the location of an inventory item. FIGURE 9-36 A magazine subscriber code is derived from various parts of the name and address. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 46 Designing Codes ◦ Keep codes concise ◦ Avoid confusion ◦ Allow for expansion ◦ Make codes ◦ Keep codes stable meaningful ◦ Make codes unique ◦ Use a code for a single purpose ◦ Use sortable codes ◦ Keep codes consistent ◦ Use a simple structure Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 47 Tools and Techniques ◦ Data warehouse An integrated collection of data that can include seemingly unrelated information, no matter where it is stored in the company ◦ Data mart Designed to serve the needs of a specific department FIGURE 9-37 A data warehouse stores data from several systems. By selecting data dimensions, a user can retrieve specific information without having to know how or where the data is stored. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 48 ◦ Data Mining (clickstream storage) Looks for meaningful data patterns and relationships Suggested goals for data mining Increase the number of pages viewed per session and referred customers Reduce clicks to close Increase checkouts per visit and average profit per checkout Can be used to build a profile of new customers Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 49 Logical versus Physical Storage ◦ Logical storage: Data that a user can view, understand, and access, regardless of how or where that information actually is organized or stored ◦ Physical storage: Strictly hardware-related Involves the process of reading and writing binary data to physical media Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 50 Data Coding ◦ EBCDIC (Extended Binary Coded Decimal Interchange Code) Used on mainframe computers and high-capacity servers ◦ ASCII (American Standard Code for Information Interchange) Used on most personal computers ◦ Binary storage format Represents numbers as actual binary values ◦ Unicode: Uses two bytes per character Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 51 FIGURE 9-38 Unicode is an international coding format that represents characters as integers, using 16 bits per character. The Unicode Consortium maintains standards and support for Unicode. ©1991–2015 Unicode, Inc. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 52 ◦ Storing dates International Organization for Standardization (ISO) requires a format of four digits for the year, two for the month, and two for the day (YYYYMMDD) FIGURE 9-39 Microsoft Excel uses absolute dates Absolute date: Total in calculations. In this example, May 4, 2015, is displayed as 42128, and September 27, 2013, is number of days from displayed as 415443. The difference between the some specific base date dates is 584 days. Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 53 A well-designed DBMS must provide built-in control and security features Forms of data protection ◦ Providing limited access to files and databases ◦ Use of user ID and password, permissions and encryption Backup copies of databases must be retained for a specified period of time ◦ Recovery procedures can be used to restore the file or database ◦ Maintain audit log files and audit fields Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 54 A database consists of linked tables that form an overall data structure ◦ DBMS enable users to add, update, manage, access, and analyze data in a database DBMS designs are more powerful and flexible than traditional file-oriented systems ◦ Components include interfaces for users, database administrators, and related systems In an information system, an entity is a person, place, thing, or event for which data is collected and maintained Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 55 Key fields include primary keys, candidate keys, foreign keys, and secondary keys An entity-relationship diagram (ERD) is a graphic representation of all system entities and the relationships among them ◦ Relationship between two entities is referred to as cardinality Normalization is a process for avoiding problems in data design A code is a set of letters or numbers used to represent data in a system Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 56 Logical storage is information seen through a user’s eyes, regardless of how or where that information actually is organized or stored File and database control measures include limiting access to the data, data encryption, backup/recovery procedures, audit-trail files, and internal audit fields Copyright ©2017 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 57
