Does this decomposition have a lossless join

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Reference no: EM133268340

Assignment:

The following are attributes in spreedsheet, none of which are null:

Manufacturer, Model_Num, Serial_Num, Description, Store, PurchaseDate, Price

Each row in this spreadsheet corresponds to a computer that they own.

1. Give a minimal set of functional dependencies F that hold for this schema assuming only that:

?The manufacturer, model number and serial number uniquely identify the store, purchase date and price;

?The description of a computer is determined by the manufacturer and model number -- in particular, it does not vary depending on the store in which the computer was bought or the serial number of the computer.

2. What is the key of your relation? Prove this by showing that the closure of the set of attributes in the key includes all attributes.

Now suppose that you decompose into R1 (Manufacturer, Model_Num, Serial_Num, Store, PurchaseDate, Price), R2(Manufacturer, Model_Num, Description).

3. Does this decomposition have a lossless join? Why or why not?

4. What is the projection of F over R1? The projection of F over R2? Does the decomposition preserve dependencies (and say why)?

Reference no: EM133268340

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