AFM341 Chapter Notes - Chapter 3: Data Structure Diagram, Entity–Relationship Model, Object Management Group
29 Dec 2013
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Charles bachman developed data structure diagrams (bachman diagrams) Model of logical database structures must be able to describe: entities or things in domain of interest, relationship, cardinalities that describe instances of one entity can be related to another, attributes or characteristics of entities and relationships. Uml class diagram notation for structure models. Object management group is a not for profit consortium that maintains and publishes specification for uml. Class diagrams are one type of diagram within uml and similar to entity relationship diagrams. Any separately identifiable collection of things about which the organization wants to collect and store information: can represent organization resources, persons, events, and conceptual structures. Implemented as tables in a relational database: each class in organized into a rectangle with three compartments: Depicts the relationship between two classes: customers participate in sales , professors teach courses. Describe the minimum and maximum number of times instances in one class can be associated with instances in another class.
