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Creating a Schema John Wright Where to Start We start with the ERD. We create a relation for each entity. We need to determine the attributes for each.

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Presentation on theme: "Creating a Schema John Wright Where to Start We start with the ERD. We create a relation for each entity. We need to determine the attributes for each."— Presentation transcript:

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2 Creating a Schema John Wright

3 Where to Start We start with the ERD. We create a relation for each entity. We need to determine the attributes for each entity.  We normally do this on the ERD, but for this exercise I will do it in the SCHEMA We then apply the rules of dependancy to normalize the relations. We then apply determine the primary/foreign key relationships. (See the other slide presentation for help in this.).

4 The ERD Publisher Book Patron Purchase Order CheckOut Publishes Contains Submitted Author Order Item Associative Entity AuthorBook Contains Associative Entity

5 Schema with Attributes Book Copy #ISBNPurchase DateAuthorIDTitlePublisherIDTypeNameAuthorID Author Purchase Order PublisherIDPONumberDate Order Item PONumberLineNumberCostTitleType Author Book AuthorIDISBN

6 Entities Publisher AddressPublisherIDRepresentativeIDCityStatezip CheckOut PatronIDISBNCKOutDate Patron AddressPatronIDFinesDueCityStatezip

7 Normalization Normally we normalize at this point. See the presentation on normalization. Normalization is determined by dependancies. Next, we add foreign keys using the rules found in the Schema presentation.

8 Foreign Keys Book Copy #ISBNPurchase DateAuthorIDTitlePublisherTypeNameAuthorID Author Purchase Order PublisherIDPONumberDate Order Item PONumberLineNumberCostTitleType Author Book AuthorIDISBN ISBN and AUTHORID are both foreign keys and composite keys PONumber is a foreign key as well as a composite key PublisherID is a foreign key to publisher table

9 Foreign Keys Publisher AddressPublisherIDRepresentativeIDCityStatezip CheckOut PatronIDISBNCKOutDate Patron AddressPatronIDFinesDueCityStatezip ISBN and PatronID are both foreign keys as well as composit keys


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