Definitions

Definitions - Data independence: To isolate application...

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Data independence : To isolate application programs as much as possible from changes to data and description of data. To make applications independent of data storage. Physical data independence : application programs immune to changes in storage structures Logical data independence : application programs immune to changes to description of unrelated data. Three-Schema architecture: Schema : description of data contents, structure, and possibly other aspects of a database External schema : describes data as seen by an application program/end user. Conceptual schema : describes the base logical structure of all data Internal schema : describes how the database is physically encoded, including selection of files, indexes etc. Binary relationship cardinalities : relationships between 2 entity sets A and B. (1:1, 1:N, N:N) General cardinality Composite attributes : attributes that have 2+ other attributes Multi-valued attributes
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This note was uploaded on 12/18/2010 for the course CS 338 taught by Professor I.i during the Winter '09 term at Waterloo.

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Definitions - Data independence: To isolate application...

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