Functional_dependencies_transcript - Relations, Functional...

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Page 1 of 2 Relations, Functional Dependencies, and Keys Audio Transcript This tutorial will provide an overview of relations, functional dependencies and keys. A relation is basically a table of information made up of rows and columns that meet certain criteria. Each item in the table must hold a single value such as a number or name of something, but not a range of information. The items in each column must be the same kind of information such as all numbers. No rows in a table can be totally identical. There must be at least one column with different information. Finally, the order of the rows and the order of the columns doesn’t matter. The information could be reordered in whatever way makes sense to the user. A functional dependency is a relationship between information in the columns in a relation. Basically it’s saying that if you have one piece, or sometimes more, of information, you can by definition know another piece of information. For example, think about your Social Security number. If you
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Functional_dependencies_transcript - Relations, Functional...

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