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Given a relation R(A, B, C, D, E, F, G, H) with keys BD and C and functional dependencies D→G, E→F and H→C, decompose the R into the highest normal form possible.

SidX asked in Databases Sep 27, 2021

by SidX

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Test by Bikram | Databases | Test 2 | Question: 30
Consider the following set of relations: EMP (eno, ename , dno) DEPT (dno, dname) Primary key columns are underlined and dno in EMP is a foreign key referring primary key of DEPT table. Now, consider the following queries: QUERY: $1$ SELECT ... Query:1 and Query:2 returns different number of columns. I, II only III, IV only II, III only I, IV only

Bikram asked in Databases Aug 26, 2017

by Bikram

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2 votes

1 answer

3

Test by Bikram | Databases | Test 2 | Question: 29
Let Depositor and Lender be relational schemas such that Depositor = {a/c number, cname , balance, branch} & Lender ={loan_number ,cname, amount , branch}. Now, consider the following queries on the database: Query $1$ ... 3 give same result. Query 1 and Query 3 give same result. Query 1, Query 2 and Query 3 give different results.

Bikram asked in Databases Aug 26, 2017

by Bikram

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1 vote

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Test by Bikram | Databases | Test 2 | Question: 28
Given below are some transaction schedules that involve three transactions $T1 \ T2 \ T3$: $\textbf{Schedule 1:}$ $T2 : Rx , T2 : Ry , T1 : Wx , T3 : Wy , T3 : Wz , T2 : Wz , T1 : Rz , T2 : Wy $ ... $1$ Schedule $2$ Schedule $3$ Schedule $4$

Bikram asked in Databases Aug 26, 2017

by Bikram

117 views

3 votes

0 answers

5

Test by Bikram | Databases | Test 2 | Question: 27
Consider the relation: Exam(eid, marks) Assume that marks take not null integers only. Also, marks takes distinct values and the number of tuples are odd. Select marks from Exam E where (select Count(*) from Exam where marks < E. ... What does the above SQL query print? Mean of the marks Median of the marks Mode of the marks Average of the marks

Bikram asked in Databases Aug 26, 2017

by Bikram

193 views

8 votes

3 answers

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Test by Bikram | Databases | Test 2 | Question: 26
Assume that a data file contains $2000$ records that are ordered by a key attribute $K$ , and a primary index on attribute $K$ is built. The size of key is $5B$ and block pointer is $5B$. Each block of the system is of ... storing meta data). The total number of disk accesses required to fetch the record using the index (in average case) is _____.

Bikram asked in Databases Aug 26, 2017

by Bikram

474 views

3 votes

1 answer

7

Test by Bikram | Databases | Test 2 | Question: 25
Consider a relational table $T$ with sufficient number of records having attributes $T1, T2, \dots ,Tn$ (where $1 \leq p \leq n)$ Two queries $S1$ and $S2$ ... queries. Hashing will outperform ordered indexing on $S2$ but not $S1$. Hashing will outperform ordered indexing on $S1$ but not $S2$.

Bikram asked in Databases Aug 26, 2017

by Bikram

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Test by Bikram | Databases | Test 2 | Question: 24
Consider the relation schemas: Rank (name, rank) and student (name, country), where name in student table is a foreign key in table Rank. Which of the following TRC Queries displays all the student names from India along with their respective ranks? ...

Bikram asked in Databases Aug 26, 2017

by Bikram

198 views

7 votes

1 answer

9

Test by Bikram | Databases | Test 2 | Question: 23
Consider the table employee' having two columns: 'EmpNo' and 'EmpName'. Run the following transaction on the table: COMMIT; ALTER TABLE employee ADD PhoneNo varchar(10); ROLLBACK; What are the columns in the table ... operation? EmpNo PhoneNo EmpNo EmpName Same as (B) but will throw an error indicating failed transaction EmpNo EmpName PhoneNo

Bikram asked in Databases Aug 26, 2017

by Bikram

372 views

2 votes

1 answer

10

Test by Bikram | Databases | Test 2 | Question: 22
Consider the following relation schema: Student (RollNo, Sname, Scity) Packages (Pcode, Pname, Price) Registers (RollNo PCode, Date) What does the following SQL query return? Select distinct S.RollNo From Student S Where NOT ... RollNos of students who registered for at least one package. RollNos of students who registered for all the packages.

Bikram asked in Databases Aug 26, 2017

by Bikram

235 views

2 votes

1 answer

11

Test by Bikram | Databases | Test 2 | Question: 21
Consider the following transaction involving two bank accounts $A$ and $B$ ... $A$ and $B$ should remain constant is that of: Atomicity Consistency Isolation Durability

Bikram asked in Databases Aug 26, 2017

by Bikram

137 views

1 vote

1 answer

12

Test by Bikram | Databases | Test 2 | Question: 20
Assume that a B-Tree is used as an index for a large database table which has six levels (including the root node). If a new key is inserted into this index, then the maximum number of levels possible in the updated tree is ______.

Bikram asked in Databases Aug 26, 2017

by Bikram

203 views

1 vote

1 answer

13

Test by Bikram | Databases | Test 2 | Question: 19
A schedule with two transactions T1 and T2 is as mentioned below: ... The above schedule is an example of: Cascade-less schedule Recoverable schedule Both Cascade-less and Recoverable schedule Irrecoverable schedule

Bikram asked in Databases Aug 26, 2017

by Bikram

140 views

2 votes

1 answer

14

Test by Bikram | Databases | Test 2 | Question: 18
The above ER diagram depicts a book rental scheme. If this ER diagram is mapped to a relational model, to correctly depict this above scenario, the total number of relations required will be _________.

Bikram asked in Databases Aug 26, 2017

by Bikram

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3 votes

2 answers

15

Test by Bikram | Databases | Test 2 | Question: 17
Which of the following is TRUE about the given schedule S? ... is conflict serializable. It is view serializable but not conflict serializable. It is conflict serializable but not view serializable. It is not serializable.

Bikram asked in Databases Aug 26, 2017

by Bikram

239 views

3 votes

2 answers

16

Test by Bikram | Databases | Test 2 | Question: 16
$\sigma_{A=B \text{ and } B=C \text{ and } C=A} \bigg( \Pi_A (R) \times \Pi_B (R) \times \Pi_C (R) \bigg)$ The number of rows returned by the above relational algebraic expression is ________.

Bikram asked in Databases Aug 26, 2017

by Bikram

258 views

3 votes

1 answer

17

Test by Bikram | Databases | Test 2 | Question: 15
What is the number of rows returned by an SQL query on the below EMP table? ... EMP where manager IN (NULL, NULL,NULL); It will throw an error. Three rows are selected. No rows are selected. One row is selected.

Bikram asked in Databases Aug 26, 2017

by Bikram

272 views

0 votes

1 answer

18

Test by Bikram | Databases | Test 2 | Question: 14
Consider the schedule $S = \{R1(A),R2(B),W2(A),W1(A)\}$ Assume that Transaction T1 has started execution before Transaction T2. Which of the following is TRUE in the above case? Allowed under Basic Timestamp ... Allowed under both Basic Timestamp Protocol and Thomas Write Rule. Not allowed under both Basic Timestamp Protocol and Thomas Write Rule.

Bikram asked in Databases Aug 26, 2017

by Bikram

192 views

1 vote

1 answer

19

Test by Bikram | Databases | Test 2 | Question: 13
Consider the following table structures: CREATE TABLE dept(dno number PRIMARY KEY, dname varchar2(30)); CREATE TABLE emp(eno number PRIMARY KEY, ename varchar2(30), dno number references dept(dno) ON DELETE CASCADE ON UPDATE CASCADE) ... . Update on DEPT is always successful. Delete on DEPT is always successful. Update on EMP is always successful.

Bikram asked in Databases Aug 26, 2017

by Bikram

263 views

2 votes

1 answer

20

Test by Bikram | Databases | Test 2 | Question: 12
Consider a table $R (A,B,C,D,E)$ where the functional dependencies are: $A \rightarrow B$ $B \rightarrow C$ $D \rightarrow E$ ... decomposition is: Dependency preserving and lossless. Dependency preserving and lossy. Neither dependency preserving nor lossless. Not dependency preserving but lossless.

Bikram asked in Databases Aug 26, 2017

by Bikram

160 views

9 votes

1 answer

21

Test by Bikram | Databases | Test 2 | Question: 11
Relation $L( p,q)$ is stored in $100$ blocks, with $50$ records per block (or tuples) of $L$ fitting in one block. Relation $K(m,n)$ is stored in $200$ blocks with $100$ ... $K$. Therefore, the total number of blocks required in the result of join operation is: ______ blocks.

Bikram asked in Databases Aug 26, 2017

by Bikram

447 views

2 votes

1 answer

22

Test by Bikram | Databases | Test 2 | Question: 10
We are using timestamp-based concurrency control, and there are two transactions T1 and T2 with timestamps 100 and 200, respectively. The following schedule is executed in the order shown below using time stamping protocols: ... Basic Timestamp Ordering Protocol and Thomas Write Rule, but is allowed under Multi-version Timestamp Ordering Protocol.

Bikram asked in Databases Aug 26, 2017

by Bikram

375 views

1 vote

1 answer

23

Test by Bikram | Databases | Test 2 | Question: 9
In a B-Tree, the block size is $512$ Bytes, search key is $4$ Bytes, block pointer size is $8$ Bytes and record pointer size is $8$ Bytes. Every node contains $n-1$ record pointers, $n-1$ search keys and n block pointers (where ... of search keys that can be accommodated in level $0$ of the above B-tree (where root is at level $0$) is _________.

Bikram asked in Databases Aug 26, 2017

by Bikram

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3 votes

1 answer

24

Test by Bikram | Databases | Test 2 | Question: 8
Consider the following schedule: ... Which of the following transaction problems is present in the given schedule ? Lost update Dirty Rea Unrepeatable read Both (A) & (B)

Bikram asked in Databases Aug 26, 2017

by Bikram

239 views

3 votes

1 answer

25

Test by Bikram | Databases | Test 2 | Question: 7
What is the highest normal form of the relation $R(ABCDEF)$ having functional dependency set at $F = \{ A \rightarrow BC, \ \ C \rightarrow AD, \ \ E \rightarrow ABC, \ \ F \rightarrow CD, \ \ CD \rightarrow BEF, \ \ AB \rightarrow D \}$? $1NF$ $2NF$ $3NF$ $BCNF$

Bikram asked in Databases Aug 26, 2017

by Bikram

229 views

3 votes

1 answer

26

Test by Bikram | Databases | Test 2 | Question: 6
Decompose the following table into BCNF: $R(ABCD)$ $A \rightarrow C$ $C \rightarrow A$ $AB \rightarrow D$ The result is: (AC) (ABD) (AC) (CBD) (AB)(BAD) Both (A) & (B)

Bikram asked in Databases Aug 26, 2017

by Bikram

356 views

1 vote

1 answer

27

Test by Bikram | Databases | Test 2 | Question: 5
Consider the following set of FDs on a relation $R(ABCDE)$: $F1 = \{ A \rightarrow B, \ AB \rightarrow C, \ D \rightarrow AC, \ D \rightarrow E \}$ $F2 = \{ A \rightarrow BC, \ D \rightarrow AE \}$ ... $F1$ covers $F2$, but $F2$ doesn't cover $F1$. $F1$ is equivalent to $F2$. $F1$ is not equivalent to $F2$.

Bikram asked in Databases Aug 26, 2017

by Bikram

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3 votes

2 answers

28

Test by Bikram | Databases | Test 2 | Question: 4
A relation $R(P,Q,R,S)$ has $\{PQ, QR, RS, PS\}$ as candidate keys. The total number of superkeys possible for relation $R$ is ______

Bikram asked in Databases Aug 26, 2017

by Bikram

442 views

0 votes

1 answer

29

Test by Bikram | Databases | Test 2 | Question: 3
Consider the following schedule: ... $W(B), W(C)$ $W(A), W(A)$ $W(A) ,W(B)$ $W(C), W(A)$

Bikram asked in Databases Aug 26, 2017

by Bikram

347 views

1 vote

2 answers

30

Test by Bikram | Databases | Test 2 | Question: 2
The relation R (ABCDE) with FD set $\{AB \rightarrow CDE, \ A \rightarrow C, \ C \rightarrow D\}$ is in which of the following normal forms? 1NF but not in 2NF in both 2NF and 3NF in 3NF but not in BCNF in BCNF

Bikram asked in Databases Aug 26, 2017

by Bikram

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Recent questions tagged tbb-dbms-2