DBMS End Term: 24 December 2023, Set ADB3 (September 2023 term)

Consider a relation CustomerLogs(Name, Items, Restaurant, Date) with the following data values.

If multivalued dependency ($Name \rightarrow\rightarrow \{Restaurant\}$) exists in the above CustomerLogs relation, then what are the values of A, B, C, D, E?

Consider the relation $\mathbf{R}(A, B, C, D, E, G)$ with the following sets of functional dependencies

$\mathcal{F} = \{AB \rightarrow C, AC \rightarrow B, AD \rightarrow E, B \rightarrow D, BC \rightarrow A, E \rightarrow G, B \rightarrow C\}$

Let the R is decomposed in two ways:

$D1 = R1(AB), R2(BC), R3(ABDE), R4(EG)$

$D2 = R1(ABC), R2(ACDE), R3(ADG)$

Which among the following statements is correct?

Consider the relation:

Items(item_name, item_type, brand, price)

There is at least one item each in the 'Food' and 'Beverage' item type categories. What will the following relational algebra expression imply?

$\begin{aligned} &\Pi_{item\_name}(\sigma_{(item\_type=\textit{'Beverage'} \wedge brand=\textit{'Keventer'})}(Items)) - \\ &\Pi_{item\_name}(Items \times_{(item\_type=\textit{'Beverage'} \wedge brand=\textit{'Keventer'} \wedge q=\textit{'Food'} \wedge price>=s \wedge r=\textit{'Amul'})} \rho_{(p,q,r,s)}(Items)) \end{aligned}$