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FIRST PUBLISH OCTOBER 2024
CS 430 Midterm #2 Study Guide Solutions
Axioms, or rules of inference, provide a simpler technique for reasoning about functional dependencies.
- ANSWER✔✔True
If a relation r is legal under a set F of functional dependencies, we say that r satisfies F. -
ANSWER✔✔True
Some functional dependencies are said to be BLANK because they are satisfied by all relations. -
ANSWER✔✔trivial
It is always possible to decompose a relation into 3NF form that is both lossless join and dependency
preserving. - ANSWER✔✔True
If we wish to constrain ourselves to relations on schema R that satisfy a set F of functional dependencies,
we say that F BLANK on R. - ANSWER✔✔holds
In general, the goal of a relational database design is to generate a set of relation schemas that allows us
to store information without unnecessary redundancy and yet allows us to retrieve information easily. -
ANSWER✔✔True
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A relation schema R is in third normal form with respect to set F of functional dependencies, if for all
functional dependencies in F+ of the form A -> B where A is a subset of R, B is an attribute of R, and at
least on e of the following holds:
* A -> B is a trivial functional dependency
* A is a superkey for R.
* B is part of a key for R.
* B is a superkey for R.
* A is part of a key for R. - ANSWER✔✔A -> B is a trivial functional dependency
A is a superkey for R.
B is part of a key for R.
A functional dependency is a form of an integrity constraint. - ANSWER✔✔True
Consider the following relation. Check all the answers below that hold for this table.
A|B|C|D
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, ©EMILLECT 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED
FIRST PUBLISH OCTOBER 2024
a1 | b1 | c1 | d1
a2 | b3 | c1 | d2
a3 | b1 | c1 | d3
a2 | b7 | c1 | d5
* ABD -> C
* D -> ABC
* AB -> D
* AB -> CD
* B -> A
* A -> BC
* BC -> AD - ANSWER✔✔ABD -> C
D -> ABC
AB -> D
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AB -> CD
Consider the relation R with attributes: A, B, C, D, E, and F. Let S be a set of functional dependencies in R
such that S = { A -> B, CD -> E, C -> D}. Which of these attributes are in the closure of {A, C, F}+?
A
B
C
D
E
F - ANSWER✔✔A
B
C
D
E
F
Page 4/61
FIRST PUBLISH OCTOBER 2024
CS 430 Midterm #2 Study Guide Solutions
Axioms, or rules of inference, provide a simpler technique for reasoning about functional dependencies.
- ANSWER✔✔True
If a relation r is legal under a set F of functional dependencies, we say that r satisfies F. -
ANSWER✔✔True
Some functional dependencies are said to be BLANK because they are satisfied by all relations. -
ANSWER✔✔trivial
It is always possible to decompose a relation into 3NF form that is both lossless join and dependency
preserving. - ANSWER✔✔True
If we wish to constrain ourselves to relations on schema R that satisfy a set F of functional dependencies,
we say that F BLANK on R. - ANSWER✔✔holds
In general, the goal of a relational database design is to generate a set of relation schemas that allows us
to store information without unnecessary redundancy and yet allows us to retrieve information easily. -
ANSWER✔✔True
Page 1/61
, ©EMILLECT 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED
FIRST PUBLISH OCTOBER 2024
A relation schema R is in third normal form with respect to set F of functional dependencies, if for all
functional dependencies in F+ of the form A -> B where A is a subset of R, B is an attribute of R, and at
least on e of the following holds:
* A -> B is a trivial functional dependency
* A is a superkey for R.
* B is part of a key for R.
* B is a superkey for R.
* A is part of a key for R. - ANSWER✔✔A -> B is a trivial functional dependency
A is a superkey for R.
B is part of a key for R.
A functional dependency is a form of an integrity constraint. - ANSWER✔✔True
Consider the following relation. Check all the answers below that hold for this table.
A|B|C|D
Page 2/61
, ©EMILLECT 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED
FIRST PUBLISH OCTOBER 2024
a1 | b1 | c1 | d1
a2 | b3 | c1 | d2
a3 | b1 | c1 | d3
a2 | b7 | c1 | d5
* ABD -> C
* D -> ABC
* AB -> D
* AB -> CD
* B -> A
* A -> BC
* BC -> AD - ANSWER✔✔ABD -> C
D -> ABC
AB -> D
Page 3/61
, ©EMILLECT 2024/2025 ACADEMIC YEAR. ALL RIGHTS RESERVED
FIRST PUBLISH OCTOBER 2024
AB -> CD
Consider the relation R with attributes: A, B, C, D, E, and F. Let S be a set of functional dependencies in R
such that S = { A -> B, CD -> E, C -> D}. Which of these attributes are in the closure of {A, C, F}+?
A
B
C
D
E
F - ANSWER✔✔A
B
C
D
E
F
Page 4/61
