Databases

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Collections of data

Reasons for a DBMS

Reasons for a DBMS (cont'd)

Database organization

Flat databases

Hierarchical databases

Hierarchical example

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Hierarchical example (cont'd)

Relational databases

Operations on tables

Relational examples

Relational examples (cont'd)

Relational examples (cont'd)

Relational examples (cont'd)

Relational examples (cont'd)

Relational examples (cont'd)

Relational examples (cont'd)

Relational implementation

Relational software

Object-oriented databases

Abstraction

Encapsulation

Modularity

Hierarchy

Examples of class hierarchies

Example of object hierarchy

Events

Object-oriented implementation

39 of 46

Centralized databases (cont'd)

Electronic Medical Records

Electronic Medical Records (cont'd)

Current efforts

Current efforts (cont'd)

Oacis

DRG system

Centralized databases

E.g., hospital information system. Complex.
Advantages:

shared data, reduced redundancy
fewer inconsistencies in data
enforcement of standards
security restrictions
balancing of conflicting requirements

Historical note: ‘The minimum computer memory required for average data bases varies from 30K to 160K bytes.’ (Fundamentals of Data Base Systems, S.M. Deen, 1977, p. 5). This memory requirement is less than the size of the level-2 cache in a current entry-level PC.

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Last modified: Wed, 2007 Mar 21 17:29:21

Slide show generated from dbms.html by Weasel 2007 Mar 21