Recent questions tagged databases / GATE Overflow for GATE CSE

0 votes

0 answers

1801

NPTEL
In an external merge sort, where number of blocks in the relation is 324, suppose we can put only 4 blocks at a time into the memory. In the worst case, how many total block transfers will happen? 1. 2592 2. 3240 3. 3888 4. 4230

In an external merge sort, where number of blocks in the relation is 324, suppose we can put only 4 blocks at a time into the memory. In the worst case, how many total bl...

gulsanchouhan

336 views

gulsanchouhan asked Aug 25, 2017

0 votes

0 answers

1802

NPTEL
Consider a B-tree with the following specifications: Page size c = 2 kB; Size of key γ = 32 bytes; Size of pointer η = 8 bytes. What is the order m of the B-tree? How many records can a tree of height 3 store? 1. m = 21, Number of records ≈9.26×103 2. m = 22, Number of records ≈1.22×104 3. m = 42, Number of records ≈7.95×104 4. m = 43, Number of records ≈8.52×104

Consider a B-tree with the following specifications: Page size c = 2 kB; Size of key γ = 32 bytes; Size of pointer η = 8 bytes. What is the order m of the B-tree? How ...

gulsanchouhan

318 views

gulsanchouhan asked Aug 25, 2017

1 votes

1 answer

1803

NPTEL
Consider a B+-tree with the following specifications: Page size c = 2 kB; Size of key γ = 32 bytes; Size of pointer η = 8 bytes. What is the order m of the B+-tree? How many records can a tree of height 3 store? 1. m = 26, Number of records ≈1.90×104 2. m = 51, Number of records ≈1.38×105 3. m = 26, Number of records ≈1.75×104 4. m = 51, Number of records ≈1.25×105

Consider a B+-tree with the following specifications: Page size c = 2 kB; Size of key γ = 32 bytes; Size of pointer η = 8 bytes. What is the order m of the B+-tree? How...

gulsanchouhan

638 views

gulsanchouhan asked Aug 25, 2017

2 votes

1 answer

1804

what is the num of superkey can we get from a1,a2...a n attributes?

hem chandra joshi

430 views

hem chandra joshi asked Aug 23, 2017

0 votes

0 answers

1805

oracle sql in date concepts
sql query for irrespective of years to find the data between 15th to 30th of july in oracle

sql query for irrespective of years to find the data between 15th to 30th of july in oracle

Sedhu Raman

296 views

Sedhu Raman asked Aug 20, 2017

1 votes

1 answer

1806

Lost Update problem
IN these questions , in T1 it will read value of A from hard disk or local buffer and W(A) when execute it will make change in local buffer or hard disk , are w(A) and commit are same because commit means we stored data in hard disk anyone explain plz in detail

IN these questions , in T1 it will read value of A from hard disk or local buffer and W(A) when execute it will make change in local buffer or hard disk , are w(A) and ...

sumit goyal 1

785 views

sumit goyal 1 asked Aug 20, 2017

0 votes

2 answers

1807

How to find Key Constraint in 1:M cardinality Entity set?
I have a problem in identifying the key constraints of the Entity set. As in the relation, the key constraint should be from M-side. But here, in this case, according to me Father is the key constraint. So for this, the relation is 1:M. In this case, it doesn't satisfy Father to be the key constraint.

I have a problem in identifying the key constraints of the Entity set. As in the relation, the key constraint should be from M-side. But here, in this case, according to...

Pavan Boro

494 views

Pavan Boro asked Aug 19, 2017

2 votes

2 answers

1808

Block Nested Loop Join
Consider a relation R with 2000 records and relation S with 500 records. Size of each record is 5 Byte and block size is 100 Byte, then minimum number of block access that are needed block nested loop join. I think its answer should be 2525.

Consider a relation R with 2000 records and relation S with 500 records. Size of each record is 5 Byte and block size is 100 Byte, then minimum number of block access tha...

Shubhanshu

1.4k views

Shubhanshu asked Aug 18, 2017

3 votes

2 answers

1809

Multiple Overlapping candidate keys

atul_21

2.0k views

atul_21 asked Aug 16, 2017

3 votes

1 answer

1810

BCNF_lossless and dependency preserving
Consider the relation $R(ABCDE)$ and functional dependency $F=\{AB \rightarrow C, C \rightarrow D,D \rightarrow E, E \rightarrow A \}.$ If we convert given relation in Boyce Codd Normal Form ( BCNF ) then In BCNF ... is not preserved In BCNF it is lossy decomposition but dependency is preserved In BCNF it is lossy decomposition but dependency not preserved

Consider the relation $R(ABCDE)$ and functional dependency $F=\{AB \rightarrow C, C \rightarrow D,D \rightarrow E, E \rightarrow A \}.$If we convert given relation in Boy...

atul_21

1.2k views

atul_21 asked Aug 16, 2017

2 votes

1 answer

1811

Relational algebra gateforum sample questions
https://gateoverflow.in/?qa=blob&qa_blobid=7899832711610886100 How can we know that when we have to use natural join and when Cartesian product??

https://gateoverflow.in/?qa=blob&qa_blobid=7899832711610886100How can we know that when we have to use natural join and when Cartesian product??

Ankit Saurav 1

800 views

Ankit Saurav 1 asked Aug 13, 2017

4 votes

3 answers

1812

Is following sql query valid?
Can a sql query be like this: SELECT name AS instructor from instructor; The attributes' name can be renamed to table name or not?

Can a sql query be like this: SELECT name AS instructor from instructor;The attributes' name can be renamed to table name or not?

vishwajit_vishnu

520 views

vishwajit_vishnu asked Aug 13, 2017

0 votes

0 answers

1813

Sql Practice
Given the following Relations: Product(pid,name,description,price,quantity) Customer(cid,name,address,phone,email) Invoice(id,cid,pid,quantity,state,datetime) Where state can be: paid, delivered, pending, or canceled. Product, Customer and Invoice schema with PRIMARY and ... List name(s) of customer(s) in decreasing order of total amount spent. 3.List the total sales for each month.

Given the following Relations:Product(pid,name,description,price,quantity)Customer(cid,name,address,phone,email)Invoice(id,cid,pid,quantity,state,datetime) Where state ca...

Pavan Kumar Munnam

2.0k views

Pavan Kumar Munnam asked Aug 13, 2017

1 votes

1 answer

1814

Two-Phase-Locking
Sort these various versions of Two Phase locking protocols in increasing order of restricted-ness: 1. 2-PL(normal) 2. S-2PL(Strict) 3. R-2PL(Rigorous) 4. C-2PL (Conservative) 5. LC-2PL(Lock Conversion)

Sort these various versions of Two Phase locking protocols in increasing order of restricted-ness:1. 2-PL(normal)2. S-2PL(Strict)3. R-2PL(Rigorous)4. C-2PL (Conservative)...

Tuhin Dutta

1.9k views

Tuhin Dutta asked Aug 13, 2017

1 votes

2 answers

1815

#Transaction-Schedules
How to order these schedules in terms of flexibility of concurrency? 1. View serializable 2. Conflict Serializable 3.Recoverable 4.Strict 5.Cascadeless

How to order these schedules in terms of flexibility of concurrency?1. View serializable2. Conflict Serializable3.Recoverable4.Strict5.Cascadeless

Tuhin Dutta

694 views

Tuhin Dutta asked Aug 12, 2017

15 votes

13 answers

1816

Minimum number of tables to represent ER-Diagram
How many minimum relations required for given ER diagram ?

How many minimum relations required for given ER diagram ?

targate2018

8.9k views

targate2018 asked Aug 12, 2017

11 votes

4 answers

1817

Minimum number of tables to represent ER-Diagram
The minimum number of tables to represent ER-Diagram such that the relational database satisfies 1NF.

The minimum number of tables to represent ER-Diagram such that the relational database satisfies 1NF.

targate2018

11.7k views

targate2018 asked Aug 11, 2017

1 votes

0 answers

1818

sql assertion

Pavan Kumar Munnam

252 views

Pavan Kumar Munnam asked Aug 7, 2017

4 votes

1 answer

1819

Dirty read & unrepeatable read
Where is unrepeatable read and dirty read taking place here?

Where is unrepeatable read and dirty read taking place here?

just_bhavana

989 views

just_bhavana asked Aug 6, 2017

1 votes

1 answer

1820

Graph based protocol
Is there a chance for Deadlock in Graph based protocol?

Is there a chance for Deadlock in Graph based protocol?

Heena Jain

688 views

Heena Jain asked Aug 5, 2017

2 votes

1 answer

1821

Serializability and strict schedules
Answer is given as D. Not serializable, agreed. But how is it strict??

Answer is given as D. Not serializable, agreed. But how is it strict??

just_bhavana

12.9k views

just_bhavana asked Aug 4, 2017

3 votes

1 answer

1822

Relational Algebra
Consider the following schema: Student (Sid, Sname, age) Course Info (Cid, Cname, Instructor SSN) Enroll (Sid, Cid, grade). The relational algebra expression for “find the Cid’s of courses enrolled by two different students” is ??

Consider the following schema:Student (Sid, Sname, age)Course Info (Cid, Cname, Instructor SSN)Enroll (Sid, Cid, grade).The relational algebra expression for “find the ...

just_bhavana

1.6k views

just_bhavana asked Aug 4, 2017

3 votes

0 answers

1823

ER diagrams and functional dependency
Let R represents an one to many relationship between entities E1 and E2 and the set A, B attributes represent the key of R (A is key for E1 and B is key for E2) then which of the following statements is correct? The FD, A→B will only holds The FD, B→A will only holds (a) and (b) hold together Neither (a) nor (b) holds

Let R represents an one to many relationship between entities E1 and E2 and the set A, B attributes represent the key of R (A is key for E1 and B is key for E2) then whic...

just_bhavana

731 views

just_bhavana asked Aug 4, 2017

1 votes

1 answer

1824

Natural Join
What will be the output of Natural Join if there is(are) common attribute(s) in two relations but no common value in these common attribute(s) ? for example Table R A B 6 9 7 1 Table S B C 7 3 5 8 R Natural Join s will be ?

What will be the output of Natural Join if there is(are) common attribute(s) in two relations but no common value in these common attribute(s) ?for exampleTable RAB6971Ta...

rdfan19

482 views

rdfan19 asked Aug 4, 2017

3 votes

2 answers

1825

Natural Join
What will be the output of Natural join if there is(are) common attribute(s) in two relations but no Common value in these common attribute(s) ? For example Table R A B 9 7 6 9 Table S B C 4 1 8 5 Output of R natural join S will be ?

What will be the output of Natural join if there is(are) common attribute(s) in two relations but no Common value in these common attribute(s) ?For example Table RAB9769T...

rdfan19

3.2k views

rdfan19 asked Aug 4, 2017

1 votes

1 answer

1826

databases

nitish

416 views

nitish asked Aug 4, 2017

1 votes

1 answer

1827

DBMS: CONCURRENCY CONTROL 2 PHASE LOCKING PROTOCOL
T1: r1(x)w1(x)r1(y)w1(y) T2: r2(y)w2(y) L is xclusive lock and U is unlock L1(y)L1(X)R1(Y)W1(Y)R1(X)W1(X)U1(X)U1(Y)L2(Y)R2(Y)W2(Y)U2(Y)? IS THIS SCHEDULE VALID UNDER A 2 PHASE LOCKING SCHEDULER????

T1: r1(x)w1(x)r1(y)w1(y)T2: r2(y)w2(y)L is xclusive lock and U is unlock L1(y)L1(X)R1(Y)W1(Y)R1(X)W1(X)U1(X)U1(Y)L2(Y)R2(Y)W2(Y)U2(Y)?IS THIS SCHEDULE VALID UNDER A 2 PH...

Shivam Gupta 3

638 views

Shivam Gupta 3 asked Aug 3, 2017

3 votes

1 answer

1828

Redundancy
how decomposition of a->cd to a->c and a->d remove redundancy in right side?

how decomposition of a->cd to a->c and a->d remove redundancy in right side?

iamHarin

471 views

iamHarin asked Jul 29, 2017

2 votes

1 answer

1829

Binary relation
Every binary relation is in a)bcnf b)3nf c)4nf d)pjnf

Every binary relation is ina)bcnfb)3nfc)4nfd)pjnf

iamHarin

1.6k views

iamHarin asked Jul 28, 2017

1 votes

1 answer

1830

database

set2018

258 views

set2018 asked Jul 26, 2017

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