ITM 102 Lecture Notes - Lecture 6: Relational Database Management System, Database, Unique Key

• School: Ryerson University
• Department: Information Technology Management
• Course: ITM 102
• Professor: n/a

Document Summary

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. Entity: person, place, thing, event about which information is maintained. Key field: identifier field used to retrieve, update, and sort a record. Data redundancy: is the presence of duplicate data in multiple data files so that the same data are stored in more than one place or location. Refers to the coupling of data stored in files and the specific programs required to update and maintain those files. A traditional file system can deliver routine schedule reports after extensive programing efforts, but it cannot deliver ad-hoc reports or respond to unanticipated information requirement timely fashion. Management may have no way of knowing who is accessing or even making changes to the organization"s data. Information cannot flow freely across different functional areas or different parts of the organization.