BMGT 402 Lecture Notes - Lecture 12: Unique Key, Candidate Key, Foreign Key

• School: University of Maryland
• Department: Business and Management
• Course: BMGT 402
• Professor: Woei- Jyh Lee

Document Summary

Bmgt402 lecture 12 chapter 12: entity-relationship modeling: entity types, entity type a. i. Group of objects with same properties, which are identified by enterprise as having independent existence a. ii. Each entity type has one name and you usually use a singular noun a. iii. A collection of the same kind of objects a. iii. 2. Set an entity type of different kinds of occurrences: examples of entity types b. i. An independent existence can be: b. i. 1. b. i. 2. Objects with a conceptual (or abstract ) existence b. i. 2. a. Viewing, inspection, sale, work experience: entity occurrence c. i. Uniquely identifiable object of an entity type: notation d. i. The entity types should be one of those rectangular box d. i. 2. d. i. 3. All does not necessarily need an attribute d. i. 4. d. ii. This is the one that we are expected to use d. iii. 2: relationship types, relationship type a. i. Set of meaningful associations among entity types: relationship occurrence b. i. Uniquely identifiable association, which includes one occurrence from each participating entity type: 12. 4 c. i.