Examine the following relation and answer the following questions. Assume these
ID: 670286 • Letter: E
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 GROUPAGE
TOY CATEGORYPRICE
Charlie 6 year olds6
Soccer ball Sports 18.44 Jimmy 5 year olds5
Hammer Tools 7.99 Robert 6 year olds6
Baseball Sports 8.99 Jimmy 5 year olds5
Soccer ball Sports 18.44 Jimmy 5 year olds5
Wrench Tools 6.99 Charlie 6 year olds6
Baseball Sports 8.99 Stewart 5 year olds5
Oracle Computer Software 399.99Explanation / Answer
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1. Is this relation in at least 1NF? Why or why not?
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Answer:
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The given relation is in 1NF. Since there no muliti-value dependencies in any of the columns.
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2. 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.
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Answer:
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In the given relation inorder to be 1NF, The table rows has to be unique.
The unique combination is as follows.
BOY,AGE,TOY
These attributes are the one which maintains the unique record, Hence this combination is
primary key combination.
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3. What normal form is this relation currently in?
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Answer:
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The relation is in still 1NF only.
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4. 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.
----------
Answer:
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Given relation
R1(BOY,GROUP,AGE,TOY,CATEGORY,PRICE) Primary key is (BOY+AGE+TOY)
The ralation is already in 1NF.
Its not in 2NF, Since as per 2NF all attributes except the primary key have functional dependency entirely to the primary key.
But in the given relation the CATEGORY and PRICE of the toy is determined by TOY name.
Hence We can move those attibute in separate table/relation.
R1(BOY,GROUP,AGE,TOY) Primary key is (BOY+AGE+TOY)
R2(TOY,CATEGORY,PRICE) Primary key is (TOY)
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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 Basebal 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 399.99Related Questions
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