Sunday, June 16, 2019

1.How are many-to-many relationships addressed in the relational model Essay

1.How are many-to-many relationships addressed in the relational sit down Provide a specific modeling other than the one in your textbook. Illustrate your answer using IE Crows Foot E-R diagrams - Essay ExampleIn a relational model, the many-to-many relationship cannot straight off be modeled. Such a relationship has to be converted into multiple one-to-many relationships first. Therefore, a many-to-many relationship is represented in the form of three tables in the model the two original tables and a junction table. For the country- spoken language example stated above, the relationship is create as shown in the figure below. The many-to-many relationship between country and language is converted into two one-to-many relationships between the two entities and the the junction table.In the junction table (CountryLanguage), the unique primary key is a composite key (CountryID, LanguageID) which is formed by the two foreign keys which refer to the primary keys of the country (Count ryID) and language (LanguageID)

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