Data Mining and Warehousing_Unit2_DB

Data Mining and Warehousing_Unit2_DB - Data Mining and...

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Data Mining and Warehousing Unit 2 Discussion Board Kregg M. Soltow June 15, 2011 American Intercontinental University Why are there so many more foreign keys in the third normal form than in the first? Is this always going to be true? We have to restore the relationships by creating foreign keys in the orders table. The foreign keys are essentially just columns that point to the primary keys in another table. This enables us to divide the information in the database into multiple tables that are better controlled to limit the use of pass-thru dependant fields. Why is it important to define the primary keys of a file correctly? What happens to the third normal form when they are incorrectly defined? First of all, the importance is in the fact that primary keys establish what content it is that are in the fields and their relation. Without the dependency that the fields with the tables and the keys share, the 3NF will not have the ability to function, which in turn effects the functionality of the 2NF. When keys are incorrectly defined the result is often
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Data Mining and Warehousing_Unit2_DB - Data Mining and...

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