Which one is correct w$.$r$.$t$.$ RDBMS$?$

primary key $$ super key $$ candidate key

primary key $$ candidate key $$ super key

super key $$ candidate key $$ primary key

super key $$ primary key $$ candidate key

The relation scheme teacher Performance $($name$,$ subject, Sal, City, PIN, Dept$)$ has the following functional dependencies:

name, city$->$ subject, sal

name$->$Dept

city$->$PIN

PIN$->$city

The highest normal form of this relation scheme is

$1$ NF

$2$ NF

$3$ NF

BCNF

Answer the query

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r $-$ s

r U s

r join s

r cross s

Consider a schema R$($A$,$ B$,$ C$,$ D$,$ E$)$ and functional dependencies A$->$BC and CD$->$E$.$ Then the decomposition of R into R$1($ABC$)$ and R$2($CDE$)$ is

dependency preserving and lossless join

lossless join but not dependency preserving

dependency preserving but not lossless join

not dependency preserving and not lossless join

Answer the question.

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Find the highest paid employee who earns more than the average salary of all employees of his company.

Find the highest paid employee who earns more than the average salary of all the employees of all the companies.

Find all employees who earn more than the average salary of all employees of all the companies.

Find all employees who earn more than the average salary of all employees of their company.

identify the correct answer.

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a

b

c

d

Minimum no$.$ of FD$\text{'}$s in canonical cover Fc of following sets of FD$$s of the relational Schema. R$=($A$,$ B$,$ C$,$ D$,$ E$)$

FDs$=\{$A $->$ BCD$,$ CD $->$AE$,$ B$->$AD$,$ E$->$AB$\}$ are

$1$

$2$

$3$

$4$

Choose the correct match.

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i$-$a$,$ ii$-$e$,$ iii$-$d$,$ iv$-$b$,$ v$-$c

i$-$c$,$ ii$-$d$,$ iii$-$e$,$ iv$-$a$,$ v$-$b

i$-$b$,$ ii$-$e$,$ iii$-$c$,$ iv$-$a$,$ v$-$d

i$-$b$,$ ii$-$e$,$ iii$-$a$,$ iv$-$c$,$ v$-$d

Consider the join of a relation R$1,$ with a relation R$2.$ If R$1$ has P number of tuples and R$2$ has Q number of tuples then the maximum and minimum sizes of the join respectively are:

P$+$Q and P If P$>$Q

P$.$Q and P$+$Q

P$+$Q and Q if Q$>$p

P$.$Q and $0$

Answer the question.

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a

b

c

d

Consider a relation R $($A$,$ B$,$ C$,$ D$,$ E$,$ F$,$ G$,$ H$),$ where each attribute is atomic, and following functional dependencies exist.

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in $1$NF but not in $2$NF

in $2$NF but not in $3$NF

in $3$NF but not in BCNF

in BCNF

Answer the question.

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$2$

$3$

$4$

$5$

Which of the following concurrency control protocol ensures both conflict serializability and free from deadlock?

Time stamp ordering

$2$ Phase locking

Both $($a$)$ and $($b$)$

None of the above

Which one of the following statements about normal forms is FALSE?

Any relation with two attributes is in BCNF

BCNF is stricter than $3$NF

Lossless, dependency$-$preserving decomposi$$tion into $3$NF is always possible

Lossless, dependency$-$preserving decomposi$$tion into BCNF is always possible

Answer the question

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only I and II

only I, III, and IV

Only II and IV

Only II$,$ III and IV

In a schema with attributes A$,$ B$,$ C$,$ D and E following set of functional dependencies are given

A $->$ B B $->$ C CD $->$ E AE $->$ D E $->$ A

Which of the following functional dependencies is NOT implied by the above set?

CD$->$AC

AD$->$ED

BC$->$CD

AC$->$BC

From the following instance of a relation scheme R $($A$,$ B$,$ C$),$ we can conclude that:

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A$->$B and B$->$C

AB$->$C and B$->$C

AC$->$B and A$->$C

BC$->$A and A$->$B

Consider the following four schedules. Which one of them is conflict serializable?

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S$1$

S$2$

S$3$

S$4$

A Relation R with FD set $\{$A$->$B$,$ C$->$A$,$ AB$->$D A$->$D$,$ D$->$A$\}.$ How many candidate keys will be there in R$?$

$1$

$2$

$3$

$4$