Hello NPTEL Learners, In this article, you will find NPTEL Data Base Management System Assignment 8 Week 8 Answers 2023. All the Answers are provided below to help the students as a reference don’t straight away look for the solutions, first try to solve the questions by yourself. If you find any difficulty, then look for the solutions.
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NPTEL Data Base Management System Assignment 8 Answers 2023:
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Q.1. Assume that immediate database modification scheme is followed in this question. Consider the following log records for transactions TO, T1, T2, T3 and T4:
If there is a crash just after step 13 and the recovery of the system is successfully completed, identify the correct action for the above scenario.
- a) After recovery completion, value of A will be 200.
- b) After recovery completion, value of C will be 800.
- c) After recovery completion, value of D will be 500.
- d) After recovery completion, value of E will be 700.
Q.2. Assume that immediate database modification scheme is followed in this question. Consider the following log records for transactions T0, T1, T2, T3 and T4:
If there is a crash just after step 14 and the recovery of the system is successfully completed, identify the correct action for the above scenario.
- a) No Action: TO, T1; Redo: T3 and Undo: T2, T4
- b) No Action: TO; Redo: T3 and Undo: T1, T2, T4
- c) No Action: T1; Redo: T2, T3 and Undo: TO, T4
- d) No Action: T1; Redo: T2, T4 and Undo: TO, T3
Q.3. Identify the cost estimation of a query evaluation plan, if 6000 blocks are required to be transferred from the disk and the required number of disk seeks are 30.
Time to transfer one block: ty = 2 milliseconds. Time for one seek: tg = 0.2 seconds.
- a) 12.2 Seconds
- b) 16 Seconds
- c) 18 Seconds
- d) 48 Seconds
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Q.4. Let us consider the following statistics for two relations Professor and Appointment Details:
Number of records of Professor: nprofessor = 4000. Number of blocks of Professor: bprofessor = 50 Number of records of Appointment Details: npppointment Details = 2000. Number of blocks of Appointment Details: bppointment Details = 20 Let us consider a natural join of Professor and Appointment Details relations (Professor» Appointment Details). Identify the required number of block transfers in the worst case (enough memory only to hold one block of each relation) using Nested-loop join and assume Professor as the outer relation.
Q.5. Consider the following state of transactions and the statements below.
T1, T2 and T3 can be ignored. 2. T2 and T4 can be ignored. 3. T3, T4 and T5 need to be redone. 4. T4 and T5 need to be redone. 5. Only T6 needs to be undone. Identify the correct group of statements from the options below.
- a) 1), 2), 3), 5)
- b) 1), 3), 4), 5)
- c) 1), 4), 5)
- d) 2), 4), 5)
Q.6. Consider the following relational schema:
Professor(pid, pname, qualification, emaillD) Department (dname, building, budget) Appointment Details(pid, dname, date, time) Two query trees are given below.
Identify the correct statement for the above two query trees.
- a) Two query trees are equivalent as identical operations (irrespective of their positions) are used in both the trees.
- b) Two query trees are not equivalent as selection or projection operation cannot be carried out before or after the natural join operation.
- c) Two query trees are equivalent and the query tree of Figure 1 will lead to more efficient query processing.
- d) Two query trees are equivalent and the query tree of Figure 2 will lead to more efficient query processing.
Q.7. Consider the following relational schema:
Professor (pid, pname, qualification, emaillD) Department (dname, building, budget) Appointment Details(pid, dname, date, time) Four relational algebra queries are given below:
Q1: (9building=‘Watson’ (7date=*2021-04-15’ (Department I Appointment Details))) Q2: (pyilding, date (Department > Appointment Details)) Q3: Tpname (Professor > Appointment Details) Q4: lpname (9professor. pid=Appointment Details.pid(ProfessorxAppointment Details)) Identify the correct options from the options given below.
- a) Q1 is equivalent to Q2.
- b) Q1 is not equivalent to Q2.
- c) Q3 is equivalent to Q4.
- d) Q3 is not equivalent to Q4.
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Q.8. Consider the following relational schema:
Professor (pid, pname, qualification, emaillD) Department (dname, building, budget) Appointment (pid, dname, date, time) A relational algebra expression given below: Tpname (Ipid, pname (“building=‘Packard’ (Professor i Appointment » Department))) Identify the most optimized relational algebra expression equivalent to the above given relational algebra expression.
- a) IIpname,pid (7building=‘Packard’ (Professor X Appointment X Department) )
- b) IIpname, pid (Professor i (Appointment MX (0pyj1ding= ‘Packard’ (Department))))
- c) lIpnane, pid (Professor i (Appointment X Ilgnane (7building=*Packard’ (Department))))
- d) IIpname (Professor » (Appointment M (7hy;1ding=”‘Packard’ (Department))))
Q.9. Consider the following two relational algebra expressions (RA) given below:
RA I : 001 (PM02 Q) = (PM0102 Q) RA II : ((PQ) AR) = (PA (QAR)) where P, Q, and R are relational algebra expressions.
Identify the correct statement(s) from the followings.
- a) Both RA I and RA II are true.
- b) Both RA I and RA II are false.
- c) RA I is true but RA II is false.
- d) RA I is false but RA II is true.
Q.10. Consider the log record of Transaction T1 with two operation instances 01 and 02 used in recovery system with early lock release, B+ tree based concurrency control.
Choose the correct set of log entries for the recovery of transactions.
- Answer: C
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About NPTEL Data Base Management System Course:
Databases form the backbone of all major applications today – tightly or loosely coupled, intranet or internet based, financial, social, administrative, and so on. Structured Database Management Systems (DBMS) based on relational and other models have long formed the basis for such databases. Consequently, Oracle, Microsoft SQL Server, Sybase etc. have emerged as leading commercial systems while MySQL, PostgreSQL etc. lead in open source and free domain. NPTEL Data Base Management System Assignment 5 Answers
- Week 1:Course Overview. Introduction to RDBMS
- Week 2:Structured Query Language (SQL)
- Week 3:Relational Algebra. Entity-Relationship Model
- Week 4:Relational Database Design
- Week 5:Application Development. Case Studies. Storage and File Structure
- Week 6:Indexing and Hashing. Query Processing
- Week 7: Query Optimization. Transactions (Serializability and Recoverability)
- Week 8:Concurrency Control. Recovery Systems. Course Summarization.
CRITERIA TO GET A CERTIFICATE:
Average assignment score = 25% of average of best 8 assignments out of the total 12 assignments given in the course. ( NPTEL Data Base Management System Assignment 5 Answers)
Exam score = 75% of the proctored certification exam score out of 100
Final score = Average assignment score + Exam score
YOU WILL BE ELIGIBLE FOR A CERTIFICATE ONLY IF AVERAGE ASSIGNMENT SCORE >=10/25 AND EXAM SCORE >= 30/75. If one of the 2 criteria is not met, you will not get the certificate even if the Final score >= 40/100.
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