ITM 102 Lecture 9: Databases and Information Management 10 26 15

• School: Ryerson University
• Department: Information Technology Management
• Course: ITM 102
• Professor: Ozgur Turetken

Document Summary

Bit: smallest unit of data; binary digit (0, 1) Byte: group of bits that represent a single character. Field: group of words or a complete number. File: group of records of same type. Entity: person, place, thing, event about which information is maintained. Attribute: one characteristic of a particular entity. Key field: identifier field used to retrieve, update, sort a record. Problems with the traditional file environment: data redundancy & 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: program-data dependence. 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. Problems with the traditional file environment: lack of flexibility.