INFS1603 Chapter Notes - Chapter 1 - 12: Database Model, Database Design, Database
23 Jul 2018
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Document Summary
Data: facts concerning things such as people, places, events, or concepts. Information: data that has been processed and presented in a form for human interpretation, often with the purpose of revealing trends or patterns. Database: collection of data over a period of time. It includes end user data and metadata to help people keep track of things. It is managed with a database management system (dbms) Data modelling is a simple abstraction of the complex real world. Data modelling can be classi ed based on their degree of abstraction: conceptual, internal - database speci c, the model we use when database is being implemented, external, physical. Internal model is trickier as it requires di erent work for di erent systems. Entity relationship modelling (er) - top down approach. What makes a good pk: should be nonnatural, instead arti cial, should be numeric, should be unique per role, preferably single attribute, no change over time, non intelligent, security-complaint.
