C ternary three entity types 14 attribute examples a

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c)Ternary (three entity types): 14. Attribute examples:
15. Examples of relationships (continued): a.Unary In an on-campus dormitory/apartment situation, this diagram shows a recursive/unary relationship among instances of the STUDENT entity type. This notation indicates only the current roommate situation between instances of the STUDENT entity type. 16.16.Effective (or effectivity) dates are used in a data model when the organization wishes to record historical data, rather than just the current instance. A few examples might include the effective date of a product price or service rate. Another example might be the start and end date of an advisors assignment to work with a student at a university (see E-R segment below). 17. A data modeler should consider extracting an attribute from one entity type and placing it in another entity type linked by a relationship when the attribute is the identifier or some
18. Special guidelines for naming relationships include:

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