Information System Analysis Information System Design 1 Output

Information System Analysis Information System Design 1

Output Design Objective Introduction Output: l Information delivered to users through the information system by way of intranets, extranets, or the WWW l Many forms: hard copy (printed reports), soft copy (screens, microforms, audio) l Analyst works closely with user to develop output: after all, it’s FOR the user anyway 2

Output Design Objective Output should be designed to: 1. Serve the intended purpose § During the information requirements determination phase of analysis, the systems analyst finds out what purposes must be served and then output is designed based on those purposes 3

Output Design Objective 2. Design Output to Fit the User § § § 4 With many users, it’s hard to personalize output Try to design what many, if not all, users need and prefer Generally, it’s more practical to create userspecific or user customizable output when designing it for a DSS or other highly interactive applications such as those on the Web

Output Design Objective 3. Designing the Appropriate Quantity of Output § § 5 More is not always better Provide what each person needs to do his/her work Don’t overload just because the system can do it Users usually want great amounts of output at one time, especially when there’s an easy way to access more information

Output Design Objective 4. Making Sure the Output is Where It’s Needed § 5. 6 Make sure it gets presented to the right users Providing the Output on Time § Could be daily, monthly, quarterly, annually, on exception, on demand § Accurate timing is critical in some organizations

Output Design Objective 6. Choosing the Right Output Method § There are trade-offs for each method in terms of cost, accessibility, flexibility, life spans, distribution, storage and retrieval possibilities, transportability, and overall impact of the data 7

Designing Screen Output – – – 8 Output is ephemeral (not permanent like printed output) Users must be instructed on which keys to press to continue reading further screens and to interact with the display Access may be controlled via password; this is not done with printed output

Designing Screen Output Guidelines for Screen Design – – 9 Keep the screen simple Keep the screen presentation consistent Facilitate user movement among screens Create an attractive screen

Designing Screen Output 10

Designing Screen Output 11

Input Design Objectives – – – 12 Ease of Use Effectiveness Accuracy Attractiveness Simplicity Consistency

Input Design Objectives Guidelines for Input Screen Design: – Making Forms Easy to Fill In – Meeting the Intended Purpose – Assuring Accurate Completion – Keeping Forms Attractive 13

Database Design l Designing data storage organization Objectives : – – 14 Availability Integrity (accurate & consistent) Efficient storage of data as well as efficient updating and retrieval. The information retrieval be purposeful

Database Design l There are two approaches to the storage of data in a computer system: – – 15 Store the data in individual files each unique to a particular application. Store data in a computer-based system involves building a database.

Database Design Database: l a database is a collection of non-redundant data which can be shared by different application systems - 16 Stresses the importance of multiple applications, data sharing Database becomes a common resource for an agency

Database Design Database: l Changes can be made to data without affecting other components of the system - 17 change format of data items (real to integer, arithmetic operations) change file structure (reorganize data internally or change mode of access) relocate from one device to another, e. g. from optical to magnetic storage, from tape to disk

Database Design l Objectives of Effective Databases: – – – 18 – Ensuring that data can be shared among users for a variety of applications. Maintaining data accurate & consistent. Availability. Evolving the needs of the users to grow. Allowing users to construct their personal view of the data. Reduced cost of software development security restrictions

Database Design Normalization l l 19 A poor database design can cripple an application, producing problems with redundancy, inaccuracy, consistency, and concurrency of your data. Normalization is a process that serves to reduce, if not eliminate, these problems with data. Normalization is the process of organizing data in the database

Database Design Normalization l 20 Redundant data wastes disk space and creates maintenance problems. If data that exists in more than one place must be changed, the data must be changed in exactly the same way in all locations which is time consuming and prone to errors.

Database Design Normalization l Inconsistent dependency is a database design that makes certain assumptions about the location of data. l Inconsistent dependencies can make data difficult to access because the path to find the data may not be logical, or may be missing or broken. 21

Database Design Normalization l The three steps of data normalization are: – – – 22 Remove all repeating groups and identify the primary key. Ensure that all nonkey attributes are fully dependent on the primary key. Remove any transitive dependencies, attributes that are dependent on other nonkey attributes.

Database Design Normalization l The process of normalization involves working through well-defined steps, called normal forms. 1. First Normal Form (1 NF) Second Normal Form (2 NF) Third Normal Form (3 NF) 2. 3. 23

Database Design Normalization 1. First Normal Form (1 NF): § 24 A database is said to be in First Normal Form when all entities have a unique identifier or key, and when every column in every table contains only a single value and doesn't contain a repeating group or composite field

Database Design Normalization 2. Second Normal Form (2 NF): § A database is in Second Normal Form when it is in First Normal Form plus every non-primary key column in the table must depend on the entire primary key, not just part of it, assuming that the primary key is made up of composite columns. 25

Database Design Normalization 3. Third Normal Form (3 NF) § 26 A database is in Third Normal Form when it is in Second Normal Form and each column that isn't part of the primary key doesn't depend on another column that isn't part of the primary key. (Any Attribute depends on candidate key)

Database Design Normalization l Additional normal forms have been defined, but are less commonly utilized. These advanced normal forms include Fourth Normal Form (4 NF), Fifth Normal Form (5 NF), Boyce Codd Normal Form (BCNF), and Domain-Key Normal Form (DK/NF). 27

Designing User Interface l 28 The user interface is the system that helps users communicate with the computer system and/or the application system

Designing User Interface Design Objectives: – – – 29 Match the user interface to the task. Make the user interface efficient. Provide appropriate feedback to users. Generate usable queries. Improve productivity of knowledge workers.

Designing User Interface Components of the User Interface: 30 – Presentation language, which is the computer-tohuman part of the transaction. – Action language that characterizes the human-tocomputer portion.

Designing User Interface Types of User Interfaces: 1. Natural-language interfaces permit users to interact with the computer in their everyday or "natural" language. 31

Designing User Interface Types of User Interfaces: 2. Question-and-answer interfaces. - 32 The computer displays a question for the user on the screen. The user enters an answer via the keyboard or a mouse click. The computer acts on that input information in a preprogrammed manner. New users may find the question-and-answer interface most comfortable.

Designing User Interface Types of User Interfaces: 3. 33 A menu interface. - A menu interface, that provides the user with an screen list of available selections. - A nested menu is a menu that can be reached through another menu.

Designing User Interface Types of User Interfaces: 4. 34 Form – Fill Interface - Form-fill interfaces are onscreen forms displaying fields containing data items or parameters that need to be communicated to the user. - Form-fill interfaces may be implemented using the Web.

Designing User Interface Types of User Interfaces: 5. 35 Command – Language Interfaces - Allow the user to control the application with a series of keystrokes, commands, phrases, or some sequence of these. - Require memorization of syntax rules. - May be an obstacle for inexperienced users.