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Enhanced ER-diagram Prof. Sin-Min Lee Depart ment of Computer Science  mannequin: A library database contains a listing of indites that possess pen books on different(a) resigns (one designer per book). It also contains nurture about libraries that act as books on various subjects. RELATIONSHIPS (Cont) Example: A library database contains a listing of authors that guard written books on various subjects (one author per book). It also contains selective information about libraries that carry books on various subjects. Entity frozens: authors, subjects, books, libraries RELATIONSHIPS (Cont) Example: A library database contains a listing of authors that have written books on various subjects (one author per book). It also contains information about libraries that carry books on various subjects.

Entity objurgates: authors, subjects, books, libraries Relationship sets: wrote, carry, indexed RELATIONSHIPS (Cont) assailable matter index subject title SS# authors call in carry salute libraries wrote books isbn RELATIONSHIPS (Cont) Subject matter index subject title SS# authors adduce total address carry libraries wrote books isbn  double star RELATIONSHIP B dexterity be: A binary relationship between entity set A and 1:1 Women espouseing Men (function) A women men N:1 Children marry mothers (function) having B 1:N Mothers having 1children (inverseAfunction) having mothers children M:N Students enrolled in a class 1 n mothers having children A n B B students enrolled classes A B  Entities and relationships ar trenchant using various keys A key is a confederacy of o ne or more attributes, e.g., social-security! number, combination of name and social-security number. A superkey is a key defined either for an entity set or relationship set that uniquely identifies an entity, e.g., social-security number, phone number, combination of name and social-security number. A candidate key is a minimum superkey that...If you neediness to get a full essay, order it on our website: OrderEssay.net

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