Copyright © 2007 Pearson Education Canada 6 Chapter Managing Data Resources

Copyright © 2007 Pearson Education Canada

6Chapter

Managing Data Resources

6.2Copyright © 2007 Pearson Education Canada

• Describe basic file organization concepts and the problems of managing data resources in a traditional file environment

• Describe how a database management system organizes information, and compare the principal database models

• Apply important database design principles

Management Information SystemsChapter 6


OBJECTIVES


• Evaluate new database trends

• Identify the challenges and key management decisions posed by data resource management

OBJECTIVES (Continued)




• Challenge: Fragmented and isolated corporate systems creating a single integrated view of customers and operations

• Solution: single integrated corporate data warehouse, using a single data model.

• Oracle 9i database provides near real-time access to customer activity, customer profitability, and customer reactions

• Illustrates the importance of managing data resources for achieving profitability

VIRGIN MOBILE AUSTRALIA CASE




File Organization Terms and Concepts

• Bit: Smallest unit of data; binary digit (0,1)

• Byte: Group of bits that represents a single character

• Field: Group of words or a complete number

• Record: Group of related fields

• File: Group of records of same type

ORGANIZING DATA IN A TRADITIONAL FILE ENVIRONMENT




File Organization Terms and Concepts

(continued)• Database: Group of related files

• Entity: Person, place, thing, event about which information is maintained

• Attribute: Description of a particular entity

• Key field: Identifier field used to retrieve, update, sort a record





The Data Hierarchy






Entities and Attributes




Problems with the Traditional File Environment

• Data Redundancy and Inconsistency: • Data redundancy: The presence of duplicate

data in multiple data files so that the same data are stored in more than one place or location

• Data inconsistency: The same attribute may have different values.





Problems with the Traditional File Environment (continued)

• Program-Data Dependence:• The coupling of data stored in files and the specific

programs required to update and maintain those files such that changes in programs require changes to the data






• Lack of Flexibility• A traditional file system can deliver routine

scheduled reports after extensive programming efforts, but it cannot deliver ad-hoc reports or respond to unanticipated information requirements in a timely fashion






• Poor security • Management may have no knowledge of who is

accessing or making changes to the organization’s data

• Lack of data sharing and availability: • Information cannot flow freely across different

functional areas or different parts of the organization.






Traditional File Processing






THE DATABASE APPROACH TO DATA MANAGEMENT

Database– a collection of data organized to serve many

applications efficiently by centralizing data and controlling redundant data

Database Management System (DBMS)– Software that permits an organization to centralize

data, manage them efficiently, and provide access to the stored data





Database Management System (continued)

• Acts as interface between application programs and physical data files

• Separates logical and design views of data

• Solves many problems of the traditional data file approach


The Contemporary Database Environment








Components of a DBMS• Data definition language: Specifies content

and structure of database and defines each data element

• Data manipulation language: Used to process data in a database

• Data dictionary: Stores definitions of data elements and data characteristics


Sample Data Dictionary Report








Types of Databases• Relational DBMS

• Hierarchical and Network DBMS

• Object-oriented DBMS





Relational DBMS• Represents data as two-dimensional tables

called relations

• Relates data across tables based on common data element

• Examples: DB2, Oracle, MS SQL Server


The Relational Data Model








Three Basic Operations in a Relational DBMS

• Select: Creates subset of rows that meet specific criteria

• Join: Combines relational tables to provide users with information

• Project: Enables users to create new tables containing only relevant information


The Three Basic Operations of a Relational DBMS






Hierarchical and Network DBMS• Hierarchical:

– Organizes data in a tree-like structure– Supports one-to-many parent-child relationships – Prevalent in large legacy systems

• Network: – Depicts data logically as many-to-many

relationships




A Hierarchical Database for a Human Resources System





The Network Data Model








Hierarchical and Network DBMS• Disadvantages:

– Outdated, not used for new applications

– Less flexible compared to RDBMS

– Lack support for ad-hoc and English language-like queries





Object-oriented Database Management Systems (OODBMS):

• Stores data and procedures as objects that can be retrieved and shared automatically

• Provides capabilities of both object-oriented and relational DBMS

Hybrid OODBMS: • combine benefits of relational and object-oriented

DBMS





Designing Databases• Conceptual design: Abstract model of database from a

business perspective • Physical design: Detailed description of business

information needs• Entity-relationship diagram: Methodology for

documenting databases illustrating relationships between database entities

• Normalization: Process of creating small stable data structures from complex groups of data


An Unnormalized Relation for ORDER

CREATING A DATABASE ENVIRONMENT




Normalized Tables Created from ORDER





An Entity-Relationship Diagram





Distributed database:• A database that is stored in more than one physical

location• Reduce the vulnerability of a single, massive central

site • Increase service and responsiveness to local users• Can often run on smaller, less expensive computers• Depend on high-quality telecommunications lines








Distributed Databases (continued)• Can be decentralized either by partitioning or

by replicating • Partitioned database:

– Parts of the database are stored in different physical locations

• Replicated database:– Duplicate the entire database at all remote

locations


Distributed Databases








Ensuring Data Quality• The quality of decision making in a firm is directly

related to the quality of data in its databases. • Data Quality Audit: Structured survey of the accuracy

and level of completeness of the data in an information system

• Data Cleansing: Consists of activities for detecting and correcting data in a database or file that are incorrect, incomplete, improperly formatted, or redundant


DATABASE TRENDS



Multidimensional Data Analysis

• Also called Online Analytical Processing (OLAP)

• Supports manipulation and analysis of large volumes of data from multiple dimensions/perspectives


Multidimensional Data Model

DATABASE TRENDS




DATABASE TRENDS

Data Warehouses and Data Mining

• Data Warehouse– A massive database that stores current and

historical data– Data are standardized into a common data model– Consolidated across entire enterprise for

management analysis and decision making




Components of a Data Warehouse

DATABASE TRENDS




DATABASE TRENDS

Data Mart• Subset of data warehouse • Contains summarized or highly focused

portion of data for a specified function or group of users

Data Mining• Tools for analyzing large pools of data• Find hidden patterns and infer rules to predict

trends




DATABASE TRENDS

Benefits of Data Warehouses

• Improved information

• Easier access to information

• Ability to model and remodel the data




DATABASE TRENDS

Databases and the Web

The Web and Hypermedia Databases

• Organizes data as network of nodes

• Links nodes in pattern specified by user

• Supports text, graphic, sound, video, and executable programs




A Hypermedia Database

DATABASE TRENDS




DATABASE TRENDS

Databases and the Web (continued)

Linking Internal Databases to the Web

• Database server: – Computer in a client/server environment runs a

DBMS to process SQL statements and perform database management tasks.

• Application server: – Software handling all application operations




Linking Internal Databases to the Web

DATABASE TRENDS




The ThomasNet.com Web database interface

DATABASE TRENDS




MANAGEMENT OPPORTUNITIES, CHALLENGES, AND SOLUTIONS

Opportunities

• Organizational performance can be improved by making better use of data– Investments in data mining and customer

relationship management technology





Challenges• Organizational obstacles to a database

environment– Need cooperation to develop corporate-wide data

administration

• Cost/benefit considerations – Bringing about significant change in the database

environment of a firm can be very expensive and time consuming





Solution Guidelines

The critical elements for creating a database environment are:

• Data administration

• Data-planning and modeling methodology

• Database technology, management and users




Key Organizational Elements in the Database Environment




Documents

Copyright © 2007 Pearson Education Canada 6 Chapter Managing Data Resources