Free Printable Spring2026.DBI202.Chapter2.Quiz

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Spring2026.DBI202.Chapter2.Quiz

Total questions: 27

Worksheet time: 20mins

Name

Class

Date

Which operator is used to select a subset of rows from a relation that satisfy a specific condition?

Projection (π)

Selection (σ)

Join (⋈)

Union (∪)

The operation that produces a new relation with a subset of columns from the original relation is called (a) .

Given R(A,B), which expression correctly selects tuples where attribute A equals 10?

π_A=10(R)

σ_A=10(R)

ρ_R(A=10)

R⋈_A=10

To combine all tuples from two union-compatible relations, we use the (a) operator.

What is the result of the Cartesian Product (R×S) if R has 3 tuples and S has 5 tuples?

8 tuples

15 tuples

3 tuples

5 tuples

The (a) operator, denoted by ⋈, combines tuples from two relations that match on all common attributes.

Which of the following is the correct symbol for the Rename operator?

If we want to find elements that are in relation R but NOT in relation S, we use the expression ________.

R - S

R \ S

Difference

All options are correct

In the expression π_name,age(σ_age>20(Students)), which operation is performed first?

Projection

Selection

Rename

Intersection

10.

A Theta-join (R⋈_θS) is equivalent to a ________ followed by a Selection.

product

cross product

cartesian product

All options are correct

11.

Which operator is used to remove duplicate tuples in its result by definition?

All relational operators

Only Union

Only Projection

None

12.

Given R(A,B) and S(B,C), the Natural Join R⋈S will have which set of attributes?

{A, B, B, C}

{A, B, C}

{A, C}

{B}

13.

To find the intersection of R and S (R∩S) using only Difference (−), the formula is ________.

R - (R - S)

S - (S - R)

R - (S - R)

S - (R - S)

14.

What condition must be met for two relations to be used in a Set Union, Intersection, or Difference?

Same number of tuples

They must be union-compatible

They must have a common key

One must be empty

15.

Which operator would you use to change the schema of a relation without changing the data?

∪

16.

The result of π_L(R) has a degree equal to the number of attributes in ________.

list L

17.

Which operation is most useful for combining data from different relations based on a common ID?

Cartesian Product

Intersection

Natural Join

Difference

18.

Relations used: Inventory (partID, partName, color), Suppliers (sid, sName, address)

and Catalog (sid, partID, cost).
Find all rows in the Inventory relation with a color attribute of 'Red'.

σ_{color=′Red′}(Inventory)

π_{color=′Red′}(Inventory)

ρ_{color=′Red′}(Inventory)

∪_{color=′Red′}(Inventory)

19.

Relations used:

Inventory (partID, partName, color)
Suppliers (sid, sName, address)
Catalog (sid, partID, cost)

Find the IDs of suppliers (sid) who supply part 'P101'. Answer: π_sid(σ_{partID=′P101′}( (a) ))

20.

Given R(A,B) and S(B,C), the Natural Join R⋈S will result in a schema with attributes ________.

{A, B, C}

{B}

{A, R.B, S.B, C}

{A, C}

21.

To find the intersection of R and S using only the Difference operator, the formula is: R−(R−?).

(a)

22.

Relations used:

Inventory (partID, partName, color)
Suppliers (sid, sName, address)
Catalog (sid, partID, cost)

Find the names of suppliers (sName) who supply 'Red' parts with a cost < 50. Answer:

π_sName(Suppliers⋈(σ_{color=′Red′} _AND cost<50(Inventory⋈ (a) )))

23.

Given:

Inventory (partID, partName, color)
Suppliers (sid, sName, address)
Catalog (sid, partID, cost)

Find partIDs (partID) supplied by both 'Supplier A' AND 'Supplier B'.

π_partID(σ_{sName=′SupplierA′}(S⋈C)) ∩ π_partID(σ_{sName=′SupplierB′}(S⋈C))

π_partID(σ_{sName=′SupplierA′}(S⋈C)) ∪ π_partID(σ_{sName=′SupplierB′}(S⋈C))

π_partID(σ_{sName=′SupplierA′ AND sName=′SupplierB′}(S⋈C))

π_partIDσ_{sName=′SupplierA′ AND sName=′SupplierB′}(S⋈C)

24.

Given:

Inventory (partID, partName, color)
Suppliers (sid, sName, address)
Catalog (sid, partID, cost)

Find the names of parts (partName) that are NOT in the Catalog.

Answer: π_partName(Inventory)−π_partName(Inventory⋈?)

(a)

25.

Relations used:

Inventory (partID, partName, color)
Suppliers (sid, sName, address)
Catalog (sid, partID, cost)

Find the addresses of suppliers in 'Hanoi' who supply 'Blue' or 'Green' parts.

Answer: π_(a)(σ_{address=′Hanoi′}(Suppliers)⋈Catalog⋈σ_{color='Blue' OR color='Green'}(Inventory))

26.

Relations used:

Inventory (partID, partName, color)
Suppliers (sid, sName, address)
Catalog (sid, partID, cost)

Find the IDs of parts supplied by at least two different suppliers.

π_C1.partID(σ_{C1.partID=C2.partID} _{AND C1.sid≠C2.sid}(ρ_C1(Catalog)×ρ_C2(Catalog)))

π_C1.partID(σ_{C1.partID=C2.partID} _{AND C1.sid≠C2.sid}(ρ_C1(Catalog)⋈ρ_C2(Catalog)))

π_C1.partID(σ_{C1.partID=C2.partID} _{OR C1.sid≠C2.sid}(ρ_C1(Catalog)×ρ_C2(Catalog)))

π_C1.partID(σ_{C1.partID≠C2.partID} _{AND C1.sid≠C2.sid}(ρ_C1(Catalog)×ρ_C2(Catalog)))

27.

Relations used:

Inventory (partID, partName, color)
Suppliers (sid, sName, address)
Catalog (sid, partID, cost)

Find the partID of parts that have the color 'Red' OR have a cost < 10.

π_partID(σ_{color=′Red′}(Inventory))∪π_partID(σ_cost<10(Catalog))

π_partID(σ_{color=′Red′}(Inventory))⋂π_partID(σ_cost<10(Catalog))

π_partID(σ_{color=′Red′}(Inventory))⋂(σ_cost<10(Catalog))

π_partID(σ_{color=′Red′}(Inventory))∪(σ_cost<10(Catalog))

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Spring2026.DBI202.Chapter2.Quiz

Total questions: 27

Worksheet time: 20mins

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