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)

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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

Centralized databases

Centralized databases (cont'd)

Electronic Medical Records

Electronic Medical Records (cont'd)

Current efforts

Current efforts (cont'd)

Oacis

DRG system

Relational databases

Data are organized as logically independent tables. Features:

‘Natural’
Not so strongly biased towards specific questions
Expresses relationships by means of shared data rather than explicit pointers
Theoretical basis: relational algebra, calculus; closure
Operations on tables (Join, Project, Select) to form new tables

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

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