Consider the following relational schema along with all the functional dependencies that hold on them.

$$\begin{aligned} & R 1(A, B, C, D, E):\{D \rightarrow E, E A \rightarrow B, E B \rightarrow C\} \\ & R 2(A, B, C, D):\{A \rightarrow D, A \rightarrow B, C \rightarrow A\} \end{aligned}$$

Which of the following statement(s) is/are TRUE?

Consider the database transactions T 1 and T 2, and data items X and Y . Which of the schedule(s) is/are conflict serializable?

Consider the following relational schema:

Students ($$\mathrm{\underline {rollno:integer}}$$, name: string, age: integer, cgpa: real)

Courses ($$\mathrm{\underline {courseno:integer}}$$, cname: string, credits: integer)

Enrolled ($$\mathrm{\underline {rollno:integer}}$$, $$\mathrm{\underline {courseno:integer}}$$, grade: string)

Which of the following options is/are correct SQL query/queries to retrieve the names of the students enrolled in course number (i.e., courseno) $1470 ?$

In a $\mathrm{B}^{+}$- tree where each node can hold at most four key values, a root to leaf path consists of the following nodes:

$$A=(49,77,83,-), B=(7,19,33,44), C=\left(20^*, 22^*, 25^*, 26^*\right)$$

The *-marked keys signify that these are data entries in a leaf.

Assume that a pointer between keys $k_1$ and $k_2$ points to a subtree containing keys in [ $k_1, k_2$ ], and that when a leaf is created, the smallest key in it is copied up into A record with key value 23 is inserted into the $\mathrm{B}^{+}$- tree.

The smallest key value in the parent of the leaf that contains $25^*$ is _________ . (Answer in integer)