ITM 100 Lecture Notes - Data Definition Language, Database Server, Data Redundancy

• School: Ryerson University
• Department: Information Technology Management
• Course: ITM 100
• Professor: Vikraman Baskaran

Document Summary

File organization concepts: 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: record: group of related fields. File organization concepts (continued: database: group of related files. Entity: person, place, thing, event about which information is maintained: attribute: description of a particular entity, key field: identifier field used to retrieve, update, sort a record. Problems with the traditional file environment: data redundancy and inconsistency, program-data dependence. Problems with the traditional file environment (continued: 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. 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.