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Webpage for Databases:
Recent questions tagged databases
5
votes
3
answers
2131
B Tree and B+ Tree
Consider a DBMS that has the following characteristics: 2KB fixed-size blocks 12-byte pointers 56-byte block headers We want to build an index on a search key that is 8 bytes long. Calculate the maximum number of records we can index with a) a 3-level B+ tree (2 levels plus the root) b) a 3-level B tree
Consider a DBMS that has the following characteristics:2KB fixed-size blocks12-byte pointers56-byte block headersWe want to build an index on a search key that is 8 bytes...
pC
4.9k
views
pC
asked
Dec 25, 2016
Databases
databases
b-tree
+
–
1
votes
1
answer
2132
made easy test series
sourojit
317
views
sourojit
asked
Dec 24, 2016
Databases
databases
+
–
5
votes
1
answer
2133
Schedule's
$1)$ Consider schedule below. Determine whether schedule is cascadeless or not ? r1(x); r2(z); r1(z); r3(x); r3(y); w1(x); c1; w3(y); c3; r2(y); w2(z); w2(y);c2
$1)$ Consider schedule below. Determine whether schedule is cascadeless or not ?r1(x); r2(z); r1(z); r3(x); r3(y); w1(x); c1; w3(y); c3; r2(y); w2(z); w2(y);c2
Prabhanjan_1
1.2k
views
Prabhanjan_1
asked
Dec 24, 2016
Databases
databases
transaction-and-concurrency
+
–
0
votes
1
answer
2134
MadeEasy Subject Test: Databases - Joins
I think the answer should be 300 because in relation Q, C and E collectively distinguish a tuple from another tuple.So there can be duplicate values in C and then the natural join of P and Q will give 300 tuples.Same case can be considered when we natural join P,Q with R. Am I correct??
I think the answer should be 300 because in relation Q, C and E collectively distinguish a tuple from another tuple.So there can be duplicate values in C and then the nat...
sourojit
233
views
sourojit
asked
Dec 24, 2016
Databases
made-easy-test-series
databases
joins
+
–
2
votes
1
answer
2135
ACE TEST SERIES:-Transaction 2pl and Time stamp based protocol
KISHALAY DAS
709
views
KISHALAY DAS
asked
Dec 22, 2016
Databases
databases
transaction-and-concurrency
conflict-serializable
test-series
+
–
1
votes
1
answer
2136
ACE-MockTest-Serializability Problem
KISHALAY DAS
405
views
KISHALAY DAS
asked
Dec 21, 2016
Databases
view-serializable
databases
conflict-serializable
+
–
3
votes
4
answers
2137
DBMS-Normalisation-Lossless Join Decomposition
KISHALAY DAS
1.1k
views
KISHALAY DAS
asked
Dec 21, 2016
Databases
databases
decomposition
database-normalization
lossless-join
+
–
2
votes
4
answers
2138
ME-FST6:Transaction,Recoverability and 2PL
KISHALAY DAS
3.0k
views
KISHALAY DAS
asked
Dec 21, 2016
Databases
transaction-and-concurrency
databases
concurrency
conflict-serializable
+
–
5
votes
2
answers
2139
Working of ANY and ALL with empty set
create table stud(id int, grade varchar(20)); insert into stud values(1, 'A'); insert into stud values(2, 'A'); insert into stud values(3, 'B'); insert into stud values(4, 'B'); // Working of ALL ... rerturns NOTHING and NOT a null. Is that an empty set? How is ANY and ALL deciding their output with respect to empty set?
create table stud(id int, grade varchar(20)); insert into stud values(1, 'A'); insert into stud values(2, 'A'); insert into stud values(3, 'B'); insert into stud values(4...
yg92
2.0k
views
yg92
asked
Dec 21, 2016
Databases
databases
sql
+
–
5
votes
3
answers
2140
GATE CSE 1988 | Question: 12iv
Select SNAME from S Where SNOin (select SNO from SP where PNOin (select PNO from P Where COLOUR='BLUE')) What relations are being used in the above SQL query? Given at least two attributes of each of these relations.
Select SNAME from S Where SNOin (select SNO from SP where PNOin (select PNO from P Where COLOUR='BLUE'))What relations are being used in the above SQL query? Given at lea...
go_editor
1.3k
views
go_editor
asked
Dec 20, 2016
Databases
gate1988
normal
descriptive
databases
sql
+
–
10
votes
3
answers
2141
GATE CSE 1988 | Question: 12iii
Describe the relational algebraic expression giving the relation returned by the following SQL query. Select SNAME from S Where SNOin (select SNO from SP where PNOin (select PNO from P Where COLOUR='BLUE'))
Describe the relational algebraic expression giving the relation returned by the following SQL query.Select SNAME from S Where SNOin (select SNO from SP where PNOin (sele...
go_editor
2.0k
views
go_editor
asked
Dec 20, 2016
Databases
gate1988
normal
descriptive
databases
sql
+
–
5
votes
1
answer
2142
GATE CSE 1988 | Question: 12iic
Using Armstrong’s axioms of functional dependency derive the following rules: $\{ x \rightarrow y, \: z \subset y \} \mid= x \rightarrow z$ (Note: $x \rightarrow y$ denotes $y$ is functionally dependent on $x$, $z \subseteq y$ denotes $z$ is subset of $y$, and $\mid =$ means derives).
Using Armstrong’s axioms of functional dependency derive the following rules:$\{ x \rightarrow y, \: z \subset y \} \mid= x \rightarrow z$(Note: $x \rightarrow y$ denot...
go_editor
1.3k
views
go_editor
asked
Dec 20, 2016
Databases
gate1988
normal
descriptive
databases
database-normalization
+
–
4
votes
1
answer
2143
GATE CSE 1988 | Question: 12iib
Using Armstrong’s axioms of functional dependency derive the following rules: $\{ x \rightarrow y, \: wy \rightarrow z \} \mid= xw \rightarrow z$ (Note: $x \rightarrow y$ denotes $y$ is functionally dependent on $x$, $z \subseteq y$ denotes $z$ is subset of $y$, and $\mid =$ means derives).
Using Armstrong’s axioms of functional dependency derive the following rules:$\{ x \rightarrow y, \: wy \rightarrow z \} \mid= xw \rightarrow z$(Note: $x \rightarrow y$...
go_editor
1.0k
views
go_editor
asked
Dec 20, 2016
Databases
gate1988
normal
descriptive
databases
database-normalization
+
–
8
votes
1
answer
2144
GATE CSE 1988 | Question: 12iia
Using Armstrong’s axioms of functional dependency derive the following rules: $\{ x \rightarrow y, \: x \rightarrow z \} \mid= x \rightarrow yz$ (Note: $x \rightarrow y$ denotes $y$ is functionally dependent on $x$, $z \subseteq y$ denotes $z$ is subset of $y$, and $\mid =$ means derives).
Using Armstrong’s axioms of functional dependency derive the following rules:$\{ x \rightarrow y, \: x \rightarrow z \} \mid= x \rightarrow yz$(Note: $x \rightarrow y$ ...
go_editor
1.3k
views
go_editor
asked
Dec 19, 2016
Databases
gate1988
easy
descriptive
databases
database-normalization
+
–
9
votes
1
answer
2145
GATE CSE 1988 | Question: 12i
What are the three axioms of functional dependency for the relational databases given by Armstrong.
What are the three axioms of functional dependency for the relational databases given by Armstrong.
go_editor
1.8k
views
go_editor
asked
Dec 19, 2016
Databases
gate1988
normal
descriptive
databases
database-normalization
+
–
0
votes
0
answers
2146
SQL Query || 2
Student (Sid,gender,marks,branch) Query: Retrieve Sid's with highest marks in their respective branch -- using RA logic SELECT Sid FROM Student EXCEPT SELECT Sid FROM Student S1,Student S2 WHERE S1.marks < S2.marks AND S1.branch = S2.branch And -- ... = T.branch AND marks = mrks Please suggest any other method to write this query in SQl , using different logic or construct.
Student (Sid,gender,marks,branch)Query: Retrieve Sid's with highest marks in their respective branch using RA logic SELECT Sid FROM Student EXCEPT SELECT Sid FROM Studen...
dd
5.2k
views
dd
asked
Dec 18, 2016
Databases
sql
databases
+
–
0
votes
1
answer
2147
select and group by - navathe
a) every column that appears in group by clause must appear in select statement. b) every column that appears in select statement must appear in group by clause out of these two what is a valid argument?
a) every column that appears in group by clause must appear in select statement.b) every column that appears in select statement must appear in group by clauseout of thes...
harveen singh
381
views
harveen singh
asked
Dec 18, 2016
Databases
databases
+
–
2
votes
2
answers
2148
SQL query || 1
Student (Sid,gender,marks,branch) Query: Retrieve Sid's who scored the highest mark? SELECT SID FROM Student EXCEPT SELECT T1.Sid FROM Student T1,Student T2 WHERE T1.marks < T2.marks What are other possible correct variation equal to this query in SQL ?
Student (Sid,gender,marks,branch)Query: Retrieve Sid's who scored the highest mark?SELECT SID FROM Student EXCEPT SELECT T1.Sid FROM Student T1,Student T2 WHERE T1.marks ...
dd
2.3k
views
dd
asked
Dec 17, 2016
Databases
sql
databases
+
–
0
votes
1
answer
2149
serializability
How it is view serializable?
How it is view serializable?
vaishali jhalani
696
views
vaishali jhalani
asked
Dec 16, 2016
Databases
databases
view-serializable
conflict-serializable
+
–
2
votes
3
answers
2150
Ace Test Series: Databases - Er Diagram
vaishali jhalani
402
views
vaishali jhalani
asked
Dec 16, 2016
Databases
ace-test-series
databases
er-diagram
+
–
0
votes
0
answers
2151
GATE CSE 1989 | Question: 12b
Consider a database with the following three relations: CREDITS (STUDENT; COURSE) OFFERS (TEACHER; COURSE) BELONGS (TEACHER; DEPARTMENT) Given below is a code in query language QUEL. Describe in one English sentence the query posed by the given QUEL program. range of s is ... range of e2 is LIST2 range of e3 is LIST3 retrieve(E1.I) where e1.I=e2.I and where e1.I=e3.I
Consider a database with the following three relations:CREDITS (STUDENT; COURSE)OFFERS (TEACHER; COURSE)BELONGS (TEACHER; DEPARTMENT)Given below is a code in query langua...
makhdoom ghaya
515
views
makhdoom ghaya
asked
Dec 15, 2016
Databases
descriptive
gate1989
databases
out-of-gate-syllabus
+
–
0
votes
0
answers
2152
Inexing
Akanksha Kesarwani
132
views
Akanksha Kesarwani
asked
Dec 13, 2016
Databases
databases
+
–
2
votes
1
answer
2153
MadeEasy Test Series: Databases - Indexing
A file is organized so that the ordering of data record is same as or close to the ordering of data block in some index. The that index is called a. Dense b. Sparse c. CLustered d. Unclustered
A file is organized so that the ordering of data record is same as or close to the ordering of data block in some index. The that index is calleda. Denseb. Sparsec. CLust...
Akanksha Kesarwani
387
views
Akanksha Kesarwani
asked
Dec 12, 2016
Databases
made-easy-test-series
databases
indexing
+
–
4
votes
2
answers
2154
Difference between record & block pointer
What is the difference between record & block pointer and any resource with diagram to know more about it? Keys and records are same or not ?
What is the difference between record & block pointer and any resource with diagram to know more about it?Keys and records are same or not ?
Akanksha Kesarwani
4.9k
views
Akanksha Kesarwani
asked
Dec 10, 2016
Databases
databases
+
–
18
votes
1
answer
2155
left biasing and right biasing in B+ tree insertion
Difference between left biasing and right biasing in B+ tree insertion, Rules to be followed for left and right biasing , Kindly explain with an example ?
Difference between left biasing and right biasing in B+ tree insertion, Rules to be followed for left and right biasing , Kindly explain with an example ?
Akanksha Kesarwani
6.3k
views
Akanksha Kesarwani
asked
Dec 10, 2016
Databases
databases
b-tree
tree
+
–
4
votes
2
answers
2156
#dbms #transaction
Consider the 2 transactions T1 and T2 and four schedules S1, S2, S3 and S4 of T1 and T2 are given below: T1: R1[X] W1[X] W1[Y] T2: R2[X] R2[Y] W2[Y] S1: R1[X] R2[X] R2[Y] W1[X] W1[Y] W2[Y] S2: R1[X] R2[X] R2[Y] W1[X] W2[Y] W1[Y] S3: R1[ ... R2[Y] R1[X] W1[X] W1[Y] W2[Y] Which of the following schedules are conflict serializable? (a) S1 and S2 (b) S2 and S3 (c) S3 only (d) S4 only
Consider the 2 transactions T1 and T2 and four schedules S1, S2, S3 and S4 of T1 and T2 aregiven below:T1: R1[X] W1[X] W1[Y]T2: R2[X] R2[Y] W2[Y]S1: R1[X] R2[X] R2[Y] W1[...
shefali1
2.7k
views
shefali1
asked
Dec 10, 2016
Databases
databases
transaction-and-concurrency
conflict-serializable
+
–
33
votes
4
answers
2157
GATE CSE 1989 | Question: 12a
The below figure shows a $B^+$ tree where only key values are indicated in the records. Each block can hold upto three records. A record with a key value $34$ is inserted into the $B^+$ tree. Obtain the modified $B^+$ tree after insertion.
The below figure shows a $B^+$ tree where only key values are indicated in the records. Each block can hold upto three records. A record with a key value $34$ is inserted...
makhdoom ghaya
8.2k
views
makhdoom ghaya
asked
Dec 9, 2016
Databases
descriptive
gate1989
databases
b-tree
+
–
2
votes
1
answer
2158
Lossy join decomposition
Rakesh K
1.3k
views
Rakesh K
asked
Dec 9, 2016
Databases
databases
database-normalization
decomposition
+
–
0
votes
2
answers
2159
Transactions
Neal Caffery
414
views
Neal Caffery
asked
Dec 8, 2016
Databases
transaction-and-concurrency
databases
+
–
0
votes
1
answer
2160
Let a, b and c be the number of entities in entity sets A, B, and C, respectively
Let a, b and c be the number of entities in entity sets A, B, and C, respectively. Let t be the maximum number of triples in the relationship set for R. Which of the following is a possible combination of values for a, b ... c=4, t=20 a =100, b=10, c=20, t=100 --could'nt understand the question.what are triples??
Let a, b and c be the number of entities in entity sets A, B, and C, respectively. Let t be the maximum number of triples in the relationship set for R. Which of the foll...
Akriti sood
2.4k
views
Akriti sood
asked
Dec 6, 2016
Databases
databases
+
–
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