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Saturday, September 19, 2009

Exercise 2.1 Database Management Systems by Raghu Ramakrishnan and Johannes Gehrke

Q. Explain the following terms briefly: attribute, domain, entity, relationship, entity set, relationship set, one-to-many relationship, many-to-many relationship, participation constraint, overlap constraint, covering constraint, weak entity set, aggregation, and role indicator.

A.

attribute: TBD

domain: TBD

entity: Real-world object distinguishable from other objects. An entity is described (in DB) using a set of attributes.

relationship: Association among two or more entities

entity set: A collection of similar entities

relationship set: Collection of similar relationships.

one-to-many relationship: TBD

many-to-many relationship: TBD

participation constraint: TBD

overlap constraint: TBD

covering constraint: TBD

weak entity set: TBD

aggregation: TBD

role indicator: TBD

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