3 - 1/10/10
 Conceptual Data Modeling •  Similar to...

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1/10/10 1 Conceptual Data Modeling Similar to software design … requirements gathering and analysis application architecture and design implementation and testing maintenance database design involves multiple steps (esp. prior to creating table deFnitions) Here we focus on conceptual design using the Entity- Relationship Model similar to the use of UML diagrams for software design 1 ECS‐165A WQ'10 Entity-Relationship (ER) Diagrams [Chen 71] 2 Employee Department Project home manager sponsor project member ssn name lot code name number name startdate enddate budget Key: En#ty Set Rela#onship Set A2ribute ECS‐165A WQ'10
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1/10/10 2 ER Terminology An “ Entity ” is an object that can be distinguished from other objects e.g., the individual “John Smith” or a particular company described using a set of attribute-value pairs one or more attributes as ids (i.e., keys) An “ Entity Type ” (aka “ Entity Set ”) is a collection of similar entities (e.g. the set of employee entities)
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3 - 1/10/10
 Conceptual Data Modeling •  Similar to...

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