Physical data independence

Data Model: A set of concepts to describe the structure of a database, and certain constraints that the database should obey. Data Model Operations: Operations for specifying database retrievals and updates by referring to the concepts of the data model. Operations on the data model may include basic operations and user-defined operations.

34p thienthanoze 12-11-2012 102 10   Download

The minimum number of Cs that can be associated with one A is 1. I know this because the existence of the C to A relationship is mandatory. The maximum number of Cs that can be associated with one A is unlimited (or many). I know this because the cardinality of the C to A relationship is 1-M.

10p thienthanoze 12-11-2012 60 2   Download

Câu 1: A problem soling technique that decomposes a system its component parts while focusing on the business problem independent of technology is: a. Cause-and-effect analysis. b. System design. c. Joint application design(JAD). d. Systems analysis. Câu 2: A database is an organized collection of ____ related data. a. None of the others answers. b. logically. c. not. d. physically.

32p itvovantien 23-06-2012 104 18   Download