Question 1

Consider a relation **CustomerLogs**(*Name*, *Items*, *Restaurant*, *Date*) with the following data values. | Name | Items | Restaurant | Date | |---|---|---|---| | Zury | Coffee | Your's cafe | 19-10-21 | | Zury | D | Our's cafe | 21-10-21 | | B | Tea | C | E | | Zury | A | Our's cafe | 19-10-21 | 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**(<u>*item_name*</u>, *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? $$\begin{aligned} &\Pi_{item\_name}(\sigma_{(item\_type=\textit{'Beverage'} \wedge brand=\textit{'Keventer'})}(Items)) - \\ &\Pi_{item\_name}(Items \times_{(item\_type=\textit{'Beverage'} \wedge brand=\textit{'Keventer'} \wedge q=\textit{'Food'} \wedge price>=s \wedge r=\textit{'Amul'})} \rho_{(p,q,r,s)}(Items)) \end{aligned}$$