Data & Databases

Technology Guide 3

File Management

BitByteFieldRecordFile

Database

Entity

Attribute

Key field

Key file management concepts include:

Hierarchy of Data

Accessing Records from Computer Files

In sequential file organization:Data records must be retrieved in the same physical sequence in which they are stored.

In direct or random file organization: Users can access records in any sequence, without regard to actual physical order on the storage medium.

Problems Arising in the File Environment

• Data redundancy: The same piece of information could be duplicated in several files.

• Data inconsistency: The actual values across various copies of the data no longer agree.

• Data isolation. Data files are likely to be organized differently, stored in different formats, and often physically inaccessible to other applications.

• Security: is difficult to enforce in the file environment.

Problems Arising in the File Environment

• Data Integrity: It is difficult to place data integrity constraints across multiple data files.

• Application/ Data independence: In the file environment, the applications and their associated data files are dependent on each other.

• The numerous problems arising from the file environment approach led to the development of databases.– Database: an organized logical grouping of related files.

Database Management Systems

• The program (or group of programs) that provides access to a database is known as a database management system (DBMS).

• There are many specialized databases, depending on the type or format of data stored.

– A geographical information database contains locational data for overlaying on maps or images.

– A knowledge database stores decision rules used to evaluate situations and help users make decisions like an expert.

– A multimedia database stores data on many media—sounds, video, images, graphic animation, and text.

Database Management Systems (cont.)

Three major components of a DBMS:

Data definition language

Data manipulation language Data dictionary

Data Definition Language (DDL)

• DDL is the language used by programmers to specify the content and structure of the database.

• A DBMS user defines views or schemes using the DDL.

– A schema - the logical description of the entire database and the listing of all the data items and the relationships among them.

– A subschema - the specific set of data from the database that is required by each application.

Data Manipulation Language (DML)

• DML is used with a third- or fourth-generation language to manipulate the data in the database.

• DML provides users with the ability to retrieve, sort, display, and delete the contents of a database.

• Requesting information from a database is the most commonly performed operation. – Structured query language (SQL) – Query-by-example (QBE)

Data Dictionary

• Data Dictionary is a file that stores definitions of data elements and data characteristics such as usage, physical representation, ownership, authorization, and security.

– A data element represents a field.

Logical Data Organization

There are three basic models for logically structuring databases:

Hierarchical

Network

Relational

Three additional models are emerging:

Multidimensional

Object-oriented

Hypermedia

The Hierarchical Model

The hierarchical model relates data by rigidly structuring data into an inverted “tree” in which records contain two elements:

1. A single root or master field, often called a key, which identifies the type location, or ordering of the records.

2. A variable number of subordinate fields that defines the rest of the data within a record.

The hierarchical structure is commonly found in many traditional business organizations and processes.

The Networked-based Model

The network model creates relationships among data through a linked-list structure in which subordinated records (members) can be linked to more than one owner.

Explicit links, called pointers, are used to link subordinates and owners. That relationship is called a set.

Many-to-many relationships are possible with a network database model—a significant advantage of the network model over the hierarchical model.

The Relational Database Model

The relational model is based on a simple concept of tables in order to capitalize on characteristics of rows and columns of data, which is consistent with real-world business situations.

– Tables are called relations, and the model is based on the mathematical theory of sets and relations.

– A row is called a tuple, and a column is called an attribute.

One of the greatest advantages of the relational model is its conceptual simplicity and the ability to link records in a way that is not predefined.

Creating Databases

• To create a database, designers must develop both a conceptual and physical design:– Conceptual design - an abstract model of the database from

the user or business perspective. • Describes how the data elements in the database are to be

grouped.

– Physical design shows how the database is actually arranged on direct access storage devices.

• Groups of data are organized, refined, and streamlined until an overall logical view of the relationships among all of the data elements in the database appears.

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Chapter 2Information Technologies: Concepts & Management

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Learning Objectives Describe strategic information systems (SIS) and explain

their advantages.

Describe Porter’s competitive forces model & how IT helps companies improve their competitive positions.

Describe Porter’s value chain model and its relationship to information technology.

Describe several other frameworks that show how IT supports the attainment of competitive advantage.

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Learning Objectives (cont.)

Describe and understand the role of web-based SIS and the nature of competition in the digital age.

Describe global competition and its SIS framework.

Describe representative strategic information systems and the advantage they provide to organizations.

Discuss implementation issues including possible failures of SIS.

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Case: Building an e-Business at Fed Ex

Problem: FedEx has kept looking ahead at every stage for opportunities to meet

customers’ needs for fast, reliable, and affordable overnight deliveries. Solution: In addition to e-Shipping Tools, FedEx is now providing integrated

solutions to address the selling & supply chain needs of its customers. Results: FedEx’s e-business model facilitates better communication and

collaboration between the various parties along the supply chains. It promotes efficiency gains by reducing costs & speeding up the order

cycle. It transforms organizations into high performance e-businesses.

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Characteristics of Information Systems

Several different information systems can exist in one organization.

A particular information system may be composed of several separate information systems.

Information systems are connected by means of electronic networks.

Interorganizational information systems involve information flow in two or more organizations.

An enterprise wide system or interorganizational information system is composed of large & small computers & hardware connected by different types of networks.

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Data, Information & KnowledgeOne of the primary goals of Information Systems is to economically process data into information or knowledge.

Data items refer to an elementary description of things, events, activities, and transactions that are recorded, classified, and stored, but not organized to convey any specific meaning.

Information is data that have been organized so that they have meaning and value to the recipient.

Knowledge consists of data or information that have been organized and processed to convey understanding, experience, accumulated learning, and expertise.

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Effectiveness and Efficiency

• ISs can help companies attain more effective and efficient business processes

– Effectiveness

• The degree to which a task is accomplished

– Efficiency

• Determined by the relationship between resources expended and benefits gained in achieving a goal

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Effectiveness and Efficiency (Cont.)

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Classifications of Information Systems

Information Systems can be classified according to;

Organizational Structure Functional Area Support Provided System Architecture Activity Supported

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Classification by Organizational Structure

• Departmental information systems. Frequently, an organization uses several application programs in one functional area or department.

• Enterprise information systems (EIS). While a departmental IS is usually related to a functional area, the collection of all departmental applications when combined with other functions’ applications comprises the enterprise wide information system.

• Interorganizational systems. Some information systems connect several organizations.

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Classification by Functional Area

The major functional information systems are the following:

The accounting information systemThe finance information systemThe manufacturing (operations/production)

information systemThe marketing information systemThe human resources management

information system

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Classification by Support Provided

The major types of systems under this classification are: Transaction processing system (TPS) Management information system (MIS) Knowledge management system (KMS) Office automation system (OAS) Decision support system (DSS) Enterprise information system (EIS) Group support system (GSS) Intelligent support system

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Evolution of Support Systems

Early 1950s

1960s

Late 1960s

Early 1970s

Transaction processing system (TPS)

Management information systems (MISs)

Office automation system (OAS)

Decision support system (DSS)

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Evolution of Support Systems (cont.)

Early 1980s Executive information systems Enterprise information systems (EISs)

Group support systems (GSSs)

Mid- 1980s Expert systems (ES) Knowledge management systems

(KMS)

1990s Artificial neural networks (ANNs)

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Case: Detecting Bombs with ANNProblem: • The Federal Aviation Administration (FAA) use statistical analysis and

expert systems to prevent terrorists from sneaking bombs aboard airplanes. Yet, these technologies cannot detect all types of explosives.

Solution: • Since 1993, artificial neural networks (ANN) have been added to

improve detection effectiveness. • The ANN is exposed to a set of historical cases and is then able to

predict the existence of explosives in new cases. Results: • The FAA hopes to detect explosives more successfully and also

minimize false alarms.

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Interrelated Support Systems

Transaction Processes

MIS

Non Computer Support

EIS

DSS

External Information

Data Warehouse

Non Computer Support

Internet, other Computer Support

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Classification by System Architecture

Information systems can be classified according to three types of architecture:

A mainframe-based system.

A standalone personal computer (PC).

A distributed or a networked computing system (several variations exist).

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Transaction Processing• Transaction processing systems (TPS) support the monitoring,

collection, storage, processing, and dissemination of the organization’s basic business transactions.

– They provide the input data for many applications involving other support systems.

– The transaction processing systems are considered critical to the success of any organization.

– The TPS collects data continuously, frequently on a daily basis, or even in “real time”.

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Functional MISs Functional Management Information Systems (MISs) are put in place

to ensure that business strategies come to completion in an efficient manner.

Typically a functional MIS provides periodic information about such topics as operational efficiency, effectiveness, and productivity by extracting information from the corporate database and processing it according to the needs of the user.

MISs can be constructed in whole or in part by end-users.

MISs are also used for planning, monitoring, and control.

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Functional MISs Sales forecast by region generated by marketing MIS.

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Classification by the Activity Supported

Another important way to classify information systems is by the nature of the activity they support. Such support can be:

– Operational– Day-to-day operations of an organization

– Managerial– Middle-management activities such as short-term

planning, organizing, and control– Strategic

– Decisions that significantly change the manner in which business is being done

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Traditional Transaction Processing Methods

• Batch processing – method of computerized processing in which business transactions are accumulated over a period of time and prepared for processing as a single unit

• On-line transaction processing (OLTP) - method of computerized processing in which each transaction is processed immediately and the affected records are updated

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Batch versus On-Line Processing

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Integration of a Firm’s TPSs

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Transaction Processing Activities

• Data collection• Data editing• Data correction• Data manipulation• Data storage• Document production and reports

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Data Processing Activities Common in Transaction Processing Systems

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Point-of-Sale Transaction System

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New Strategic Systems• Electronic commerce (EC) has become a new way of

conducting business in the last decade or so. – In this new model, business transactions take place via

telecommunications networks, primarily the Internet. – e-Commerce provides organizations with innovative and

strategic advantages, such as;• Increased market share • Better ability to negotiate with suppliers• Better ability to prevent competitors from entering into

their territory

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Information Systems & People

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Information Infrastructure

There are five major components of the infrastructure: Computer hardware Development software Networks and communication facilities

(including the Internet and intranets) Databases Information management personnel

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Information Architecture Information architecture is a high-level map or plan of the

information requirements in an organization.

In preparing information architecture, the designer requires two kinds of information:1. The business needs of the organization—that is, its objectives

and problems, and the contribution that IT can make. 2. The information systems that already exist in an organization

and how they can be combined among themselves or with future systems to support the organization’s information needs.

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Types of Information Architecture

Mainframe environment. In the mainframe environment, processing is done by a mainframe computer.

– The users work with passive (or “dumb”) terminals, which are used to enter or change data and access information from the mainframe.

PC environment. In the PC configuration, only PCs form the hardware information architecture.

Networked (distributed) environment. Distributed processing divides the processing work between two or more computers.