CIS 2109 Midterm: Data Modeling
2 Nov 2017
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Document Summary
Data models define how the logical structure of a database is modeled. Data models are fundamental entities to introduce abstraction in a dbms. Data models define how data is connected to each other and how they are processed and stored inside the system. The very first data model could be flat data-models, where all the data used are to be kept in the same plane. Earlier data models were not so scientific; hence they were prone to introduce lots of duplication and update anomalies. Entity-relationship er model is based on the notion of real-world entities and relationships among them. While formulating real-world scenario into the database model, the er model creates entity set, relationship set, general attributes and constraints. Er model is best used for the conceptual design of a database. Entities and their attributes: relationships among entities. Entity an entity in an er model is a real-world entity having properties called attributes.
