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Consider a relation R(A, B, C, D, E, F) with the following functional dependencies: 1. A → BC 2. C → D 3. B → E 4. E → F
Using the attribute closure method, is A → F derivable from the given FDs?
Consider a relation R(P, Q, R, S, T) with functional dependencies: 1. PQ → R 2. R → S 3. S → T
R is decomposed into R1(P, Q, R) and R2(R, S, T).
Is this decomposition dependency preserving?
Which of the following is true about an entity in an ER model?
What is a weak entity?
Suppose we have the following schema:
,
,
describing, respectively, people, types of cars, and cars and their owners. The data corresponding to these tables is as follows:
| ID | NAME |
| 1 | Madeleine |
| 2 | Alice |
| 3 | Nalini |
| CarTypeId | Type |
| 1 | Small |
| 2 | Medium |
| 3 | Large |
| CarId | OwnerId | CarTypeId | CarName |
| 1 | 1 | 1 | Nano |
| 2 | 2 | 2 | Santro |
Select the correct returned tuple of the following SQL query:
select distinct Q.name from (select P.name, C.carName, CT.carTypeId from Person P left outer join Car C on (C.ownerId = P.id) inner join CarType CT on (C.carTypeId = CT.carTypeId)) as Q
Assuming set semantics, State true or false for the following statement:
The full outer-join operator ⟗ can be expressed as a combination of (⟕, ⟖, ∪).
Which of the following is NOT a type of attribute in an ER model?
What does cardinality in an ER model define?
Assuming set semantics, State true or false for the following statement:
The grouping operator 𝛾, can be expressed as a combination of (σ, Π, ∪).
Which of the following relational algebra expression(s) will Find courses that are either taught by Professor A or taken by Student X but not both? (Note: there can be more than expressions)