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Chapter 6

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Department
Information Technology Management
Course
ITM 102
Professor
Vikraman
Semester
Summer

Description
Chapter 6 Databases and Information and ManagementOpening Case Can HP mine success from an Enterprise Data WarehouseHPs experience illustrates the importance of data management and databases systems for business The company was unable to fully understand how it was performing as a company or how to make timely decisions because its data were terminated and inconsistent among different systems and applicationsHow businesses store organize and manage their data has a tremendous impact on organizational effectivenessHPs management determined that profitability and efficiency were shortened because it was not consistent By creating a model for a single view of the company and a database reflecting this model for companywide querying and reporting HP has become much more efficient and it managers are making better decisions Diagram61 Organizing Data in a Traditional File EnvironmentEffective information systems provide users with accurate timely and relevant information Accurate information is free of errors A computer system organizes data in a hierarchy that starts with bits and bytes and progresses to fields records files and databases Bit the smallest unit of data a computer can handle A group of bits is called a byte represents a single character which can be a letter a number or another symbol Field a grouping of characters into a word group of words or a complete number such as a persons name or ageRecord a group of related fields such as a students name the course taken date and gradeFile a group of records of the same typeA record describes an entity an entity is a person place thing or event about which we store and maintain information Each characteristic or quality describing a particular entity is called an attribute DiagramData redundancy is the presence of duplicate data in multiple data files so that the same data can be stored in more than one place or location Data redundancy occurs when different groups in an organization independently collect the same piece of data and store it independently or each other Data redundancy wastes storage and also leads to data inconsistency where the same attribute may have different valuesProgram data dependence refers to the coupling of data stored in files and the specific programs required updating and maintaining those files so that changes in programs require changes to the data Every traditional computer program has to describe the location and nature of the data with which it works In a traditional file environment any change in a software program could require a change in the data accessed by that program 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 because there is little control or management of data access to and dissemination of information may be out of control Management may have no way of knowing who is accessing or even making changes to the organizationLack of Data sharing and Availability because pieces of information in different files and different parts of the organization cannot be related to one another it is virtually impossible for information to be shared or accessed in a timely manner Information cannot flow freely across different functional areas or different parts of the organization62 The Database Approach to Data ManagementA database management system is software that permits an organization to centralize data manage them efficiently and provide access to the stored data by application programsDBMS acts as an interface between application programs and the physical data files When the application program calls for a data item such as gross pay the DBMS finds this item in the database and presents it to the application programThe DBMS relieves the programmer or end user from the task of understanding where and how the data are actually stored by separating the logical and physical views of the data
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