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Advantages and disadvantages, architectures and data models 1 Lecture 3.

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Presentation on theme: "Advantages and disadvantages, architectures and data models 1 Lecture 3."— Presentation transcript:

1 Advantages and disadvantages, architectures and data models 1 Lecture 3

2 Advantages and disadvantages, architectures and data models 2 Advantages redundancies can be reduced sometime redundant data is necessary inconsistencies can be avoided data can be shared data independence improved maintenance of the IS

3 Advantages and disadvantages, architectures and data models 3 Advantages integrity can be maintained security can be imposed concurrent access can be achieved better recovery mechanism ISs conflicting requirements can be balanced

4 Advantages and disadvantages, architectures and data models 4 Disadvantages complexity seem to require more work (skills, time, resources …) eventually it pays off higher impact of failure possibly, reduced local performance

5 Advantages and disadvantages, architectures and data models 5 The client-server architecture

6 Advantages and disadvantages, architectures and data models 6 (Totally) Distributed database systems

7 Advantages and disadvantages, architectures and data models 7 Data models recall: physical data independence how is data described and manipulated at the conceptual/logical level? concepts operators grammatical rules (these apply to any formal language)

8 Advantages and disadvantages, architectures and data models 8 A theoretical model (theory) - Lego

9 Advantages and disadvantages, architectures and data models 9 Data models the relational model the entity relationship (E/R) model E/R diagram the enhanced E/R model (EE/R) the object oriented model the object/relational model the logic model

10 Advantages and disadvantages, architectures and data models 10 Data modelling and database development

11 Advantages and disadvantages, architectures and data models 11 Course syllabus - main topics generalities the relational model SQL database design / modelling data protection advanced topics / new trends

12 Advantages and disadvantages, architectures and data models 12 Activity Have you ever used a theoretical model? Have you ever done Maths? Have you ever programmed? How is music described? Can you see any similarities between these disciplines? Can you infer a model for data modelling based on a theoretical model you know and the requirements for data modelling?


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