ITEC 3220 Study Guide - Midterm Guide: Database Design, Dependency Graph, Unique Key

• School: York University
• Department: Information Technology
• Course: ITEC 3220
• Professor: Zijiang Yang

Document Summary

Information: produced by processing data and reveals meaning of data. Data: raw facts; constitute building blocks of information. Database: shared, integrated computer structure housing end user data and metadata. Dbms: a collection of programs that manages the database structure and controls access to the data stored in the database. Data hierarchy: data > field > record > file. Disadvantages of file processing: data dependence. Change in file"s data (cid:272)ha(cid:396)a(cid:272)te(cid:396)isti(cid:272)s (cid:396)e(cid:395)ui(cid:396)es modification of data access programs: structural dependence. Change in file structure requires modification of related programs: data redundancy. Different and conflicting versions of same data. Database system environment: hardware, software, people, procedures, data. Database models: conceptual models: logical nature of data representation. Implementation models: emphasis on how the data are represented in the database. Hierarchical database model: logically represented by an upside down tree. Network database model: each record can have multiple parents.