Database Design Multiple Choice This question is based on the ER/EER model we le

Question

Database Design Multiple Choice

This question is based on the ER/EER model we learned during the CLP class sessions and in the PowerPoint lecture-note files. Let us apply class material: we are given the following conceptual schema. It shows all the attributes. The correct corresponding correct, complete, and non-redundant logical database schema is: (a) CHEF(Chef-ID. Chef-Name, Dish-ID, Dish-Creation-Date) AND SIGNATURE-DISHfDish Name) (b) SIGNATURE-DISH(Dish-ID. Dish-Creation-Date) and CHEF(Chef-ID. Chef-Name) (c) SIGNATURE DISH(Dish-ID. Dish-Name, Dish-Creation-Date, Chef-ID) and CHEF(Chef-ID. Chef-Name, Dish-ID) (d) SIGNATURE-DISH(Dish-ID. Dish-Name, Dish-Creation-Date, Chef-ID) and CHEF(Chef-ID. Chef-Name) (e) None of (a) through (d) is the correct answer.

Explanation / Answer

The ER model states that "A chef ceates N signature dishes." AND "1 signature dish can only be created by 1 chef on a particular date"

So when we proceed to table creation, it would be wise for us to include chef ID and creation date with the signature dish so that the table remains normalized and optimized.

So the most apt approach would be as said id option (d) SIGNATURE-DISH(Dish-ID. Dish-Name, Dish-Creation-Date, Chef-ID) and CHEF(Chef-ID. Chef-Name)

if you look into table a and c you will find dish information is somehow put into chefs table which is not the optimized approach!

and in b the join would be lossy since there is no common attribute (which should be the candidate key of other table) in the schema

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