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Ryerson University
Information Technology Management
ITM 100
Deb Fels

Chapter 6: Databases and Information Management 6.1- Organizing Data in a Traditional File Environment  Information systems provides users accurate (free of errors), timely (when its available to decision makers) and relevant (when its useful) information. File organization Terms and Concepts Data organization 1. Bit- represents smallest unit of data 2. Byte- a single character, letter, number or symbol 3. Field- grouping of characters into a word/sentences. 4. Record- a group of related fields EG. student names, course taken, grade and date 5. File- group of records of the same type. 6. Database- a group of related files 7. Entity- a person, place, thing or event 8. Attributes- characteristic describing an entity EG. Student ID , course, grade and date Problems with the traditional file environment Each application requires its own file and its own computer programs. Eg. HR has a personnel master file, a payroll file, medical insurance file, a pension file….. etc…. There are resulting problems such as: Data redundancy and Inconsistency- data redundancy is duplicate data in multiple data files (stored in more than one place). It occurs when different groups of organization collect the same amount of data. Data inconsistency is the same attribute, but may have a different value. Program-Data Dependence- coupling of data stored in files and specific programs required to update and maintain those files so that changes in programs require changes to the data. Lack of flexibility- file system deliver routine reports after extensive programming efforts, but it cannot deliver ad hoc reports or respond to unanticipated information requirements. Poor Security- Management cannot track who is accessing and making changes to organization’s data because there is little control or management of data. Lack of Data Sharing and Availability- it is impossible for information to be shared or accessed in a timely manner. Information cannot flow freely to different parts of the organization. 6.2 The Database Approach to Data Management  Data is stored so it appears to users being stored only in one location Database Management Systems: Database Management Systems (DBMS) is software that permits an organization to centralize data, manage them efficiently, and provide access to the stored data. It acts as an interface between applications and data files. DBMS relieves programmer from the task of understanding where/how the data is stored. Logical view presents data as it would be perceived by business specialists Physical views show how data are actually stored, structured and organized. How a DBMS solves the problems of the traditional file environment: reduces data redundancy and inconsistency by minimizing isolated files. It may not enable the organization to eliminate data redundancy. DBMS uncouples programs and data, enabling data to stand on its own. Access and availability of information is increased. It enables the organization to centrally manage data, their use, and security through use if a data dictionary. Relational DBMS: most popular type of DBMS today for PC’s as well as for larger computers and mainframes is the relational DBMS. It represents databases as 2-D tables. They are also referred to as files. For example: Microsoft Access is an example of relationa
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