Data+Modeling - Data Modeling Douglas Havelka Miami...

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Unformatted text preview: Data Modeling Douglas Havelka Miami University Data modeling Model representation of the real world To understand To communicate Represents requirements Limited to a specific domain, scope, boundaries Graphical and narrative Process Iterative Simple to complex For implementation Data structures (tables) Rules (relationships and metadata) Data manipulation method (relationships) Quality = ???? Complete Correct Understandable Useable Importance Communication Different perspectives Levels of mgmt Business units Functions Application programming Abstraction (Generalization) Level of detail Hierarchical decomposition Stepwise refinement Top-down or bottom-up Model components Entity Attributes Relationships Constraints Entity Person, place, thing, or event For which we need to store data Represents real world object (type) A set of similar things Instances are elements of the set Entity or object types (objects or instances): Customer (Bob Jones) Sale (for $568 at 10am etc.) Flight (Delta 345) Class (MIS245, Section A) Attribute Characteristic of the entity (type) Implemented by fields in file systems Attribute v values CustomerName Bob Smith Relationships or Associations An association between instances of entities Student & ClassSection Each STUDENT can take multiple CLASSSECTIONS Each CLASSSECTION can be taken by multiple STUDENTS Bi-directional! Three types of relationships: 1:1 1:M M:M 1:M...
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This note was uploaded on 04/01/2012 for the course MIS 245 taught by Professor Havelka during the Spring '12 term at Miami University.

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Data+Modeling - Data Modeling Douglas Havelka Miami...

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