DATA RESOURCE MANAGEMENT. Data Hierarchy in a Computer System. Entitities and Attributes. Problems with the Traditional File Environment. Data redundancy Program-Data dependence Lack of flexibility Poor security Lack of data-sharing and availability. Figure 7-3.
Traditional File Processing
Relational Data Model
Three Basic Operations in a Relational Database
Elements of SQL
Basic SQL Commands
Problem: If student #219
transfers we lose all references
to Golf and its price.
This is a Better Design!
Solution: make a separate table for each set of attributes with a primary key (parser, append query)
Solution: Remove to a separate table (Make Table)
Put expression in text control or in query:
=Quantity * Price
"A warehouse is a subject-oriented, integrated, time-variant and non-volatile collection of data in support of management's decision making process".
Bill Inmon (1990)
"A Data Warehouse is a repository of integrated information, available for queries and analysis. Data and information are extracted from heterogeneous sources as they are generated.…”