Examine the following relation and answer the following questions. Assume these

Question

Examine the following relation and answer the following questions. Assume these are the values that exist for all time (e.g., the toys shown always cost the amount shown) and that boys with the same name are the same person.

AGE

PRICE

6

5

6

5

5

6

5

Is this relation in at least 1NF? Why or why not?

Assuming the values shown are the only possible tuples for all time, what is the primary key of the initial relation? Remember that a primary key must be unique and not null.

What normal form is this relation currently in?

Describe the specific modification anomalies that exist if we DELETE the tuple containing Stewart.

If necessary, decompose the initial relation into a set of non-loss 3NF relations by showing the relations, attributes, and tuples. Show complete relations with attribute headings and all data values in the tuples of your relations. Determine the number of 3NF relations you end up with after normalization, write this number, and then circle the number.

BOY GROUP

AGE

TOY CATEGORY

PRICE

Charlie 6 year olds

6

Soccer ball Sports 18.44 Jimmy 5 year olds

5

Hammer Tools 7.99 Robert 6 year olds

6

Baseball Sports 8.99 Jimmy 5 year olds

5

Soccer ball Sports 18.44 Jimmy 5 year olds

5

Wrench Tools 6.99 Charlie 6 year olds

6

Baseball Sports 8.99 Stewart 5 year olds

5

Oracle Computer Software 399.99

Explanation / Answer

Is this relation in at least 1NF? Why or why not?

Ans:

In 1NF any row must not contain a column in which more than one values is stored means each row as a unit is unique.

So Yes it is in 1NF.

Primary Key:

In this table we cannot identified a row uniqueness with one column that’s why We have to combine multiple column to have primary key.

So {BOY,TOY} together work as primary key, by this we can find out a unique row in table.

This relation is in 1NF.

As there is only one record for Stewart If we delete this row then we will loss entire record of stewart. That is why we use Normalization so that we can track user information from other table.

Decomposing in 3NF

BOY

GROUP

AGE

Charlie

6 year olds

6

Jimmy

5 year olds

5

Robert

6 year olds

6

Stewart

5 year olds

5

BOY

TOY

Charlie

Soccer ball

Jimmy

Hammer

Robert

Baseball

Jimmy

Soccer ball

Jimmy

Wrench

Charlie

Baseball

Stewart

Oracle

TOY

CATEGORY

PRICE

Soccer ball

Sports

18.44

Hammer

Tools

7.99

Wrench

Tools

6.99

Baseball

Sports

8.99

Oracle

Computer Software

399.99

So we have 3 relation after normalise it to 3NF.

BOY

GROUP

AGE

Charlie

6 year olds

6

Jimmy

5 year olds

5

Robert

6 year olds

6

Stewart

5 year olds

5

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