CIS 3530 Study Guide - Midterm Guide: Relational Model, Unique Key, Big Data

• School: University of Guelph
• Department: Computing and Information Science
• Course: CIS 3530
• Professor: Fangjyu Wang

Document Summary

A model for the conceptual design on a database. Because the design is independent of hardware or software. After choosing the hardware and software we will do physical design. We call the result of the conceptual design using er model an er schema. Entity instance is an individual event within an entity type. Entity sets are a group of entity instances. Each entity type has attributes, they describe properties or relationships of the entity. Every entity type must have either a primary key or partial key (if the entity is weak). Know the di erences between relationship type, relationship etc. Degree of a relationship type is the number of participating entity types. Unary, binary are the most common, but ternary or n-ary exists also. Very important because if you have the wrong cardinality ratio here you will get it wrong in the translation.