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Recent questions tagged databases
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721
DBMS Korth Edition 4 Exercise 15 Question 2 (Page No. 588)
Suppose that there is a database system that never fails. Is a recovery manager required for this system ?
Suppose that there is a database system that never fails. Is a recovery manager required for this system ?
akash.dinkar12
338
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
transaction-and-concurrency
descriptive
+
–
0
votes
1
answer
722
DBMS Korth Edition 4 Exercise 15 Question 1 (Page No. 588)
List the $ACID$ properties. Explain the usefulness of each.
List the $ACID$ properties. Explain the usefulness of each.
akash.dinkar12
282
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
transaction-and-concurrency
descriptive
+
–
0
votes
0
answers
723
DBMS Korth Edition 4 Exercise 11 Question 20 (Page No. 491)
How does data encryption affect index schemes ? In particular, how might it affect schemes that attempt to store data in sorted order ?
How does data encryption affect index schemes ? In particular, how might it affect schemes that attempt to store data in sorted order ?
akash.dinkar12
282
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
hashing
descriptive
+
–
0
votes
1
answer
724
DBMS Korth Edition 4 Exercise 12 Question 16 (Page No. 491)
Why is a hash structure not the best choice for a search key on which range queries are likely ?
Why is a hash structure not the best choice for a search key on which range queries are likely ?
akash.dinkar12
1.6k
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
hashing
descriptive
+
–
1
votes
1
answer
725
DBMS Korth Edition 4 Exercise 12 Question 12 (Page No. 490)
Suppose that we are using extendable hashing on a file that contains records with the following search-key values: $2, 3, 5, 7, 11, 17, 19, 23, 29, 31$ Show the extendable hash structure for this file if the hash function is $h(x)$ $=$ $x$ $mod$ $8$ and buckets can hold three records.
Suppose that we are using extendable hashing on a file that contains records with the following search-key values:$2, 3, 5, 7, 11, 17, 19, 23, 29, 31$Show the extendable ...
akash.dinkar12
2.4k
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
hashing
descriptive
+
–
0
votes
1
answer
726
DBMS Korth Edition 4 Exercise 12 Question 11 (Page No. 491)
What are the causes of bucket overflow in a hash file organization ? What can be done to reduce the occurrence of bucket overflows ?
What are the causes of bucket overflow in a hash file organization ? What can be done to reduce the occurrence of bucket overflows ?
akash.dinkar12
635
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
hashing
descriptive
+
–
0
votes
1
answer
727
DBMS Korth Edition 4 Exercise 12 Question 10 (Page No. 491)
Explain the distinction between closed and open hashing. Discuss the relative merits of each technique in database applications.
Explain the distinction between closed and open hashing. Discuss the relative merits of each technique in database applications.
akash.dinkar12
1.1k
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
hashing
descriptive
+
–
2
votes
1
answer
728
DBMS Korth Edition 4 Exercise 12 Question 5 (Page No. 490)
Construct a $B^+$-tree for the following set of key values: $(2, 3, 5, 7, 11, 17, 19, 23, 29, 31)$ Assume that the tree is initially empty and values are added in ascending order. Construct B+-trees for the cases where the number of pointers that will fit in one node is as follows: a. Four b. Six c. Eight
Construct a $B^+$-tree for the following set of key values:$(2, 3, 5, 7, 11, 17, 19, 23, 29, 31)$Assume that the tree is initially empty and values are added in ascending...
akash.dinkar12
1.5k
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
indexing
b-tree
descriptive
+
–
1
votes
4
answers
729
DBMS Korth Edition 4 Exercise 12 Question 4 (Page No. 489)
Is it possible in general to have two primary indices on the same relation for different search keys ? Explain your answer.
Is it possible in general to have two primary indices on the same relation for different search keys ? Explain your answer.
akash.dinkar12
1.4k
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
indexing
descriptive
+
–
0
votes
1
answer
730
DBMS Korth Edition 4 Exercise 12 Question 3 (Page No. 489)
What is the difference between a primary index and a secondary index ?
What is the difference between a primary index and a secondary index ?
akash.dinkar12
321
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
indexing
descriptive
+
–
0
votes
0
answers
731
DBMS Korth Edition 4 Exercise 12 Question 2 (Page No. 489)
Since indices speed query processing, why might they not be kept on several search keys ? List as many reasons as possible.
Since indices speed query processing, why might they not be kept on several search keys ? List as many reasons as possible.
akash.dinkar12
311
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
indexing
descriptive
+
–
0
votes
0
answers
732
DBMS Korth Edition 4 Exercise 12 Question 1 (Page No. 489)
When is it preferable to use a dense index rather than a sparse index ? Explain your answer.
When is it preferable to use a dense index rather than a sparse index ? Explain your answer.
akash.dinkar12
252
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
indexing
descriptive
+
–
0
votes
0
answers
733
DBMS Korth Edition 4 Exercise 11 Question 18 (Page No. 442)
Consider a relational database with two relations: $course (course-name, room, instructor)$ $enrollment (course-name, student-name, grade)$ Define instances of these relations for three courses, each of which enrolls five students. Give a file structure of these relations that uses clustering.
Consider a relational database with two relations:$course (course-name, room, instructor)$$enrollment (course-name, student-name, grade)$Define instances of these relatio...
akash.dinkar12
301
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
file-organization
descriptive
+
–
0
votes
0
answers
734
DBMS Korth Edition 4 Exercise 11 Question 17 (Page No. 442)
List two advantages and two disadvantages of each of the following strategies for storing a relational database: $a$. Store each relation in one file. $b$. Store multiple relations (perhaps even the entire database) in one file.
List two advantages and two disadvantages of each of the following strategies for storing a relational database:$a$. Store each relation in one file.$b$. Store multiple r...
akash.dinkar12
270
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
file-organization
descriptive
+
–
0
votes
0
answers
735
DBMS Korth Edition 4 Exercise 11 Question 16 (Page No. 442)
In the sequential file organization, why is an overflow block used even if there is, at the moment, only one overflow record ?
In the sequential file organization, why is an overflow block used even if there is, at the moment, only one overflow record ?
akash.dinkar12
169
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
file-organization
descriptive
+
–
0
votes
0
answers
736
DBMS Korth Edition 4 Exercise 11 Question 14 (Page No. 442)
Explain why the allocation of records to blocks affects database-system performance significantly.
Explain why the allocation of records to blocks affects database-system performance significantly.
akash.dinkar12
176
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
file-organization
descriptive
+
–
0
votes
0
answers
737
DBMS Korth Edition 4 Exercise 11 Question 10 (Page No. 441)
Give an example of a database application in which the pointer method of representing variable-length records is preferable to the reserved-space method.Explain your answer.
Give an example of a database application in which the pointer method of representing variable-length records is preferable to the reserved-space method.Explain your answ...
akash.dinkar12
192
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
file-organization
descriptive
+
–
0
votes
0
answers
738
DBMS Korth Edition 4 Exercise 11 Question 9 (Page No. 441)
Give an example of a database application in which the reserved-space method of representing variable-length records is preferable to the pointer method. Explain your answer.
Give an example of a database application in which the reserved-space method of representing variable-length records is preferable to the pointer method. Explain your ans...
akash.dinkar12
126
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
file-organization
descriptive
+
–
0
votes
0
answers
739
DBMS Korth Edition 4 Exercise 11 Question 2 (Page No. 440)
How does the remapping of bad sectors by disk controllers affect data-retrieval rates ?
How does the remapping of bad sectors by disk controllers affect data-retrieval rates ?
akash.dinkar12
254
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
file-organization
descriptive
+
–
0
votes
0
answers
740
DBMS Korth Edition 4 Exercise 11 Question 1 (Page No. 440)
List the physical storage media available on the computers you use routinely.Give the speed with which data can be accessed on each medium.
List the physical storage media available on the computers you use routinely.Give the speed with which data can be accessed on each medium.
akash.dinkar12
263
views
akash.dinkar12
asked
Apr 1, 2019
Databases
korth
databases
file-organization
descriptive
+
–
0
votes
2
answers
741
Self doubt on 2PL protocol
How can 2PL protocol ( simple one ) ensure conflict serializability even though it cannot ensure freedom from deadlock ? I mean ,if a schedule is conflict serializable it has a conflict equivalent to a serial schedule and serial schedules won't have deadlocks .Right ?
How can 2PL protocol ( simple one ) ensure conflict serializability even though it cannot ensure freedom from deadlock ?I mean ,if a schedule is conflict serializable it...
ashunimbz
552
views
ashunimbz
asked
Mar 30, 2019
Databases
-2phaselocking
conflict-serializable
transaction-and-concurrency
databases
+
–
0
votes
1
answer
742
DBMS Korth Edition 6 Exercise 3 Question 24 (Page No. 111)
Consider the query: with dept total (dept name, value) as (select dept name, sum(salary) from instructor group by dept name), dept total avg(value) as (select avg(value) from dept total) select dept name from dept total, dept total avg where dept total.value >= dept total avg.value; Rewrite this query without using the with construct.
Consider the query:with dept total (dept name, value) as (select dept name, sum(salary) from instructor group by dept name), dept total avg(value) as (select avg(value) f...
ajaysoni1924
1.4k
views
ajaysoni1924
asked
Mar 30, 2019
Databases
databases
korth-edition6
relational-model
sql
+
–
0
votes
0
answers
743
DBMS Korth Edition 6 Exercise 3 Question 23 (Page No. 111)
Consider the query: select course id, semester, year, sec id, avg (tot cred) from takes natural join student where year = 2009 group by course id, semester, year, sec id having count (ID) >= 2; Explain why joining section as well in the from clause would not change the result.
Consider the query:select course id, semester, year, sec id, avg (tot cred)from takes natural join studentwhere year = 2009group by course id, semester, year, sec idhavin...
ajaysoni1924
730
views
ajaysoni1924
asked
Mar 30, 2019
Databases
databases
korth-edition6
relational-model
sql
descriptive
+
–
0
votes
1
answer
744
DBMS Korth Edition 6 Exercise 3 Question 22 (Page No. 110)
Rewrite the where clause where unique (select title from course) without using the unique construct.
Rewrite the where clausewhere unique (select title from course)without using the unique construct.
ajaysoni1924
683
views
ajaysoni1924
asked
Mar 30, 2019
Databases
databases
korth-edition6
relational-model
sql
descriptive
+
–
0
votes
0
answers
745
DBMS Korth Edition 6 Exercise 6 Question 17 (Page No. 254)
Let R = (A, B) and S = (A, C), and let r (R) and s(S) be relations. Write SQL Queries equivalent to the following domain relational- calculus expressions: a. {< a > | $\exists b (< a, b > \epsilon¸r \wedge b$ = 17)} b. ... ))}
Let R = (A, B) and S = (A, C), and let r (R) and s(S) be relations.Write SQL Queries equivalent to the following domain relational-calculus expressions:a. {< a | $\exist...
ajaysoni1924
560
views
ajaysoni1924
asked
Mar 30, 2019
Databases
databases
korth-edition6
relational-model
relational-calculus
sql
+
–
0
votes
0
answers
746
DBMS Korth Edition 6 Exercise 7 Question 25 (Page No. 321)
Consider the relation schemas are shown below, which were generated from the E-R diagram in Figure given below. For each schema, specify what foreign key constraints, if any, should be created. teaches (ID, course id, sec id, semester, ... room number) inst dept (ID, dept name) stud dept (ID, dept name) course dept (course id, dept name)
Consider the relation schemas are shown below, which were generatedfrom the E-R diagram in Figure given below. For each schema, specify what foreign keyconstraints, if an...
ajaysoni1924
1.2k
views
ajaysoni1924
asked
Mar 30, 2019
Databases
databases
korth-edition6
relational-model
er-diagram
descriptive
+
–
1
votes
0
answers
747
dbms ace test series
SQL view is said to be updatable (that is, inserts, updates or deletes can be applied on the view) if which of the following conditions are satisfied by the query defining the view? 1. The select clause contains only attribute names of the relation, and ... clause has only one database relation. 3. The query does not have a group by or having clause. 4. All of the mentioned
SQL view is said to be updatable (that is, inserts, updates or deletes can be applied on the view) if which of the following conditions are satisfied by the query definin...
Priyansh Singh
321
views
Priyansh Singh
asked
Mar 29, 2019
Databases
databases
test-series
+
–
1
votes
1
answer
748
Ace Test Series: Databases-Sql Query
Given the following schema: employees(emp-id, first-name, last-name, hire-date, dept-id, salary) departments(dept-id, dept-name, manager-id, location-id) You want to display the last names and hire dates of all latest hires in their ... pairwise comparison. $3.$It executes but does not give the correct result. $4.$It executes and gives the correct result.
Given the following schema:employees(emp-id, first-name, last-name, hire-date, dept-id, salary)departments(dept-id, dept-name, manager-id, location-id)You want to display...
Priyansh Singh
678
views
Priyansh Singh
asked
Mar 29, 2019
Databases
databases
ace-test-series
sql
+
–
0
votes
1
answer
749
DBMS Korth Edition 6 Exercise 7 Question 29 (Page No. 321)
Explain the distinction between total and partial constraints.
Explain the distinction between total and partial constraints.
ajaysoni1924
801
views
ajaysoni1924
asked
Mar 28, 2019
Databases
databases
korth-edition6
database-design
er-diagram
descriptive
+
–
0
votes
1
answer
750
DBMS Korth Edition 6 Exercise 7 Question 28 (Page No. 321)
Explain the distinction between disjoint and overlapping constraints.
Explain the distinction between disjoint and overlapping constraints.
ajaysoni1924
825
views
ajaysoni1924
asked
Mar 28, 2019
Databases
databases
korth-edition6
database-design
er-diagram
descriptive
+
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