ITM 100 Lecture Notes - Lecture 5: Data Redundancy, Management System, Mapreduce

• School: Ryerson University
• Department: Information Technology Management
• Course: ITM 100
• Professor: Al Natour

Document Summary

Database: an organized collection of data stored centrally to serve various information system applications. Attribute description of a particular entity( things that describe that entity)ex, ur age, name and address, database ab courses is the course codes. Keyfield identifier field used to retrieve, update, sort a record. Data redundancy, presence of duplicate data in multiple files. Program-data dependance, when changes in program requires changes to data accessed by program. 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. The coupling of data stored in files and the specific program required to update and maintain those files such that. Changes in data require changes to the program. Ex. one program might be modified from 5 digit to 7 digit zip code, a change in tax rate. A traditional file system can deliver routine scheduled reports after extensive programming efforts.