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0
votes
1
answer
1
Virtual Gate Test Series: Theory Of Computation - Decidable Language
$L$ is surely decidable if (A) both $L$ and its complement are not recognizable (B) $L \subseteq \{0\}^*$ (C) $L \leq_m \{0^n1^n\;\mid\;n\geq0\}$ (D) $L^R$ is decidable
$L$ is surely decidable if (A) both $L$ and its complement are not recognizable (B) $L \subseteq \{0\}^*$(C) $L \leq_m \{0^n1^n\;\mid\;n\geq0\}$(D) $L^R$ is decidable
778
views
asked
Jan 26, 2016
Theory of Computation
theory-of-computation
decidability
virtual-gate-test-series
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–
2
votes
1
answer
2
Virtual Gate Test Series: Databases - Aggregation
Which of the following is not true? Generalization is the result of taking the union of two or more disjoint entity sets to produce a higher level entity set. Specialization is an abstraction in which ... condition. The concurrency control management component of the database is responsible for handling the concurrency control policies.
Which of the following is not true?Generalization is the result of taking the union of two or more disjoint entity sets to produce a higher level entity set.Specializatio...
520
views
asked
Jan 26, 2016
Databases
databases
canonical-cover
database-normalization
virtual-gate-test-series
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–
2
votes
3
answers
3
Virtual Gate Test Series: Programming & DS - AVL Tree
Insert the given values in the order in initially empty $\text{AVL}$ tree. $\text{34,21,10,27,24,43,15,6}$ What is the value at the root of the tree$?$
Insert the given values in the order in initially empty $\text{AVL}$ tree.$\text{34,21,10,27,24,43,15,6}$What is the value at the root of the tree$?$
751
views
asked
Jan 26, 2016
DS
data-structures
tree
avl-tree
virtual-gate-test-series
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–
6
votes
3
answers
4
Virtual Gate Test Series: Discrete Mathematics - Graph Theory (Matching Number)
Find the matching number for the given graph-
Find the matching number for the given graph-
892
views
asked
Jan 26, 2016
Graph Theory
discrete-mathematics
graph-theory
graph-matching
virtual-gate-test-series
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–
0
votes
1
answer
5
Is there an easy way to check whether a given decomposition of a relation is lossless and dependency preserving ?
Given relation and the FDs applicable on it. How to check whether a given decomposition is lossless and dependency preserving?I know that for lossless we can easily chec...
788
views
asked
Jan 22, 2016
Databases
databases
dependency-preserving
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–
1
votes
2
answers
6
Calculating time compleity of recurrence relations.
I am having some problems in calculating time complexities for recurrence relations. In one of the books, I saw two questions- 1. A(n) { if(n<=1) return (n); else { return ( A(n/2)+ A(n/2)+ n); } } The recurrence for this is given as T(n)= T(n/2)+ ... )+T(n/2) +c if n>1 I think it should be T(n)= 2T(n/2)+6T(n/2) +n^2 What am I missing here ?
I am having some problems in calculating time complexities for recurrence relations. In one of the books, I saw two questions-1.A(n){if(n<=1) return (n);else{ return ( A(...
381
views
asked
Jan 17, 2016
Algorithms
algorithms
recurrence-relation
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–
5
votes
3
answers
7
What is the correct implementation of UP operation in a binary semaphore
these are the codes for down and up operations in a binary semaphore. The down operation's code seems to be correct, but I am having some doubt in the UP's code. Suppose a process p1 arrives and executes ... down, it will be forced to sleep again.. Am I missing something, or is the above implementation incorrect ?
these are the codes for down and up operations in a binary semaphore. The down operation's code seems to be correct, but I am having some doubt in the UP's code.Suppose a...
2.5k
views
asked
Dec 19, 2015
Operating System
operating-system
semaphore
process-synchronization
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–
5
votes
4
answers
8
Determine the highest possible normal form of the given relation?
Given R(ABCD) and AB → C ; ABD → C ; ABC → D ; AC → D which the highest possible normal form for the above relation ?
Given R(ABCD) andAB → C ;ABD → C ;ABC → D ;AC → Dwhich the highest possible normal form for the above relation ?
5.3k
views
asked
Dec 17, 2015
Databases
database-normalization
databases
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–
3
votes
3
answers
9
What is the highest normal form the given relation is in ?
Given a relation R (ABCD), and the following FDs- A->BCD BC->AD D->B. which is the highest normal form the table is in. a) 1NF b) 2NF c)3NF d) BCNF
Given a relation R (ABCD), and the following FDs- A->BCDBC->ADD->B.which is the highest normal form the table is in.a) 1NFb) 2NFc)3NFd) BCNF
10.0k
views
asked
Dec 16, 2015
Databases
database-normalization
databases
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–
4
votes
1
answer
10
What is the best way to check for 3nd, BCNF, partial and transitive and partial dependencies ?
I am revising DBMS for the GATE exam... Often I find it confusing that which dependency should be considered as partial , which should be considered as transitive..due to which my deductions about the ... give me a resource from where I can learn about this clearly and get my doubts cleared . Thanks
I am revising DBMS for the GATE exam... Often I find it confusing that which dependency should be considered as partial , which should be considered as transitive..due to...
874
views
asked
Dec 16, 2015
Databases
databases
database-normalization
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–
3
votes
2
answers
11
How to determine a partial functional dependency when checking for second normal form ?
What is the best and the most accurate way to check if a given functional dependency is partial on the set of FDs given. Earlier, I used to follow {part of CK -> non prime ... ://stackoverflow.com/questions/25747802/partial-dependencydatabases ) see answer by 'Mike Sherrill 'Cat Recall''
What is the best and the most accurate way to check if a given functional dependency is partial on the set of FDs given. Earlier, I used to follow {part of CK - non prime...
2.2k
views
asked
Oct 19, 2015
Databases
database-normalization
databases
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–
4
votes
2
answers
12
How is this schedule not allowed in Strict 2PL, but allowed in 2PL ?
$\begin{bmatrix} T1 &T2 \\ R(A) & \\ W(A)& \\ & R(A)\\ & W(A)\\ &R(B) \\ &W(B) \\ & Commit\\ Abort& \end{bmatrix}$ How is this schedule allowed in 2PL ? In 2PL ... phase in , which is not present in T2 ..? This example is given in the book by Raghu Ramkrishnan on page 529 and 552 (for reference)
$\begin{bmatrix} T1 &T2 \\ R(A) & \\ W(A)& \\ & R(A)\\ & W(A)\\ &R(B) \\ &W(B) \\ & Commit\\ Abort& \end{bmatrix}$How is this schedule allowed in 2PL ? In 2PL , there mus...
2.5k
views
asked
Oct 7, 2015
Databases
databases
transaction-and-concurrency
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–
2
votes
2
answers
13
In 2 Phase locking protocol, how does a deadlock happen ?
According to 2-phase locking protocol, if a transaction acquires an exclusive lock on any object, another transaction cannot obtain any kind of lock on it till the first transaction unlocks it. Is the reverse also true, i.,e., if ... cannot acquire any kind of lock on it..? or it cannot acquire exclusive lock, but can acquire shared lock. ?
According to 2-phase locking protocol, if a transaction acquires an exclusive lock on any object, another transaction cannot obtain any kind of lock on it till the first ...
2.3k
views
asked
Sep 29, 2015
Databases
databases
transaction-and-concurrency
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–
0
votes
1
answer
14
Suppose for insertion in a b+ tree of order 3, the values are inserted in order 73,108,100.
Suppose for insertion in a b+ tree of order 3, the values are inserted in order 73,108,100. What will be the structure of the resulting tree? I have watched few lectures on b+ trees and in one of the ... that will result in- Which of the above methods should I use. I am confused as to me both seem right
Suppose for insertion in a b+ tree of order 3, the values are inserted in order 73,108,100. What will be the structure of the resulting tree? I have watched few lecture...
797
views
asked
Sep 25, 2015
Databases
b-tree
databases
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–
0
votes
2
answers
15
Why is there a need for Tree-based indexing mechanisms ?
In DBMS, why is there a need for the use of tree based indexing algorithms, when we have multilevel indexes available for use ?
In DBMS, why is there a need for the use of tree based indexing algorithms, when we have multilevel indexes available for use ?
677
views
asked
Sep 25, 2015
Databases
databases
b-tree
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–
0
votes
1
answer
16
In a B tree, Suppose the search Key is 9 bytes long, the disk block size is 512 bytes...
Here, the value of p should be 24, not 23 as taken...also no reason is given for this assumption by the author (Navathe ). Can anyone explain this ?
Here, the value of p should be 24, not 23 as taken...also no reason is given for this assumption by the author (Navathe ). Can anyone explain this ?
1.5k
views
asked
Sep 25, 2015
Databases
databases
b-tree
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–
0
votes
1
answer
17
Why does a B tree contain only unique values , whereas a B+ tree can contain repeated values ?
I was reading the chapter on multilevel indexes , given in the Elmasi Navathe book. The following points have been given for key values in b and b+ trees- B trees- and for B+ trees, Why are values repeated ... not in a B tree ? How is thing possible ? Can someone please explain this by giving an example.
I was reading the chapter on multilevel indexes , given in the Elmasi Navathe book. The following points have been given for key values in b and b+ trees-B trees-and for ...
630
views
asked
Sep 25, 2015
Databases
databases
b-tree
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–
1
votes
3
answers
18
How to check the view serializability of a given schedule ?
Suppose we have a schedule containing two transactions as shown- ... , for A we will get t1->t2, and for B we will get t1->t2.. Same graph will be obtained if we draw a single polygraph
Suppose we have a schedule containing two transactions as shown-$\begin{bmatrix} T1 & T2 \\ R(A) & \\ W(A) & \\ & R(A) \\ & W(A) \\ R(B)& \\ W(B)& \\ & R(B) \\ & W(...
1.5k
views
asked
Sep 18, 2015
Databases
databases
transaction-and-concurrency
view-serializable
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–
8
votes
1
answer
19
What is the difference between a Strict schedule and a Cascadeless schedule ?
I am unable to differentiate between a strict schedule and a cascadeless schedule...although what I have understood is that in strict schedule, we cannot perform read/write till the other transaction commits..but isnt this condition also valid for cascadeless schedules ? Can someone please explain by giving an example.
I am unable to differentiate between a strict schedule and a cascadeless schedule...although what I have understood is that in strict schedule, we cannot perform read/wri...
10.8k
views
asked
Sep 18, 2015
Databases
databases
transaction-and-concurrency
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–
2
votes
1
answer
20
What is the result of a condition when a subquery returns zero tuples ?
I was reading an article regarding the use of ALL, SOME, ANY operatorshttps://oracle-base.com/articles/misc/all-any-some-comparison-conditions-in-sql . In the ALL section, it was mentioned that "If a subquery returns ... different for two operators ? It should evaluate to false for both the cases. What am I missing here ?
I was reading an article regarding the use of ALL, SOME, ANY operatorshttps://oracle-base.com/articles/misc/all-any-some-comparison-conditions-in-sql . In the ALL section...
724
views
asked
Sep 15, 2015
Databases
databases
sql
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