In a particular schedule, transaction T2 reads a value previously written by transaction T1 and transaction T3 reads a value previously written by T2. Which of the following ensures the schedule to be cascade less schedule?

Relation R with an associated set of functional dependencies, F is decomposed in to BCNF. The redundancy in the resulting set of relation is

For relation R(ABCDE), the given FD's are A$\rightarrow$BC, BC$\rightarrow$E and E$\rightarrow$DA, similarly S be a relation with attributes ABCDE and with FD's A$\rightarrow$BC, B$\rightarrow$E and E$\rightarrow$DA. Which among R and S are in BCNF?

Consider the following: $r(R):$r is a relation with attribute R $s(S):$s is a relation with attribute S $|x|:$denotes natural join operation X: denotes Cartesian product operation Then $r|xs=r \times s|:$ if

With regard to the expressive power of the former relational query language, which of the following statements is true?

Set F of functional dependencies for relation schema R(A, B, C, D, E) is A$\rightarrow$BC, CD$\rightarrow$E, B$\rightarrow$D, E$\rightarrow$A. Determine the number of candidate's keys for R.

Given R(A,B, C, D, E) and $ F = \{ B \rightarrow, AB \rightarrow C, CD \rightarrow E \} \text{ and } D = \{BE, ABDE\}$be decomposition. What is the highest normal form of decomposition D?

Given R(A,B, C, D, E) and $ F = \{ B \rightarrow, AB \rightarrow C, CD \rightarrow E \} \text{ and } D = \{BE, ABDE\}$be decomposition.

What is the highest normal form of R?

Consider the following relation R (A, B, C, D, E, F) with FD set A$\rightarrow$BCDEF BC$\rightarrow$ADEF B$\rightarrow$F D$\rightarrow$E The highest normal form achieved by R is

Consider the schema R = (S, T, U, V) and dependencies S$\rightarrow$T, T$\rightarrow$U, U$\rightarrow$V and V$\rightarrow$S. Let R$R = \{ R_1 \text{ and } R_2 \}$be a decomposition such that $R_1 \cap R_2 = \phi$. The decomposition is

Let r(R) and s(S) be relations and let $S \le R$, the division operation R/S can be expressed as

Consider the relation schema: Parts (Pno, pname) Supplier (Sid, Sname) SP (sid, pno, qty) The SQL query which display all the parts having more than one supplier is

Consider a relation: R(A, B, C, D) with FD A$\rightarrow$BCD BC$\rightarrow$AD D$\rightarrow$B The highest normal form achieved by R is

Suppose a schedule with two transactions $T_1 \& T_2$:

The above schedule is

Consider the following schedule: $R_1(A,B), R_2(B,C), R_3(B,C), V_1, V_2, V_3, W_1(A), W_3(C)$, where R stands for reads, W stands for write and V for validation. What will happen if above schedule is checked and is tested under optimistic concurrency control protocol?

Let $R_1 \left(\underline{A}, B, C\right)$ and $R_2\left(\underline{D}, E \right) $ be two relation schema, where the primary keys are shown underlined, and let C be a foreign key in $R_1$ referring to $R_2$. Suppose there is no violation of the above referential integrity constraint in the corresponding relation instances $r_1$ and $r_2$. Which of the following relational algebra expressions would necessarily produce an empty relation?

The total number of function dependencies (both trivial and non trivial) that can be formed over relation having degree = n are