Recent questions and answers in Databases - GATE CSE Doubts

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Entity Relationship Diagram
Knowledge about mapping cardinalities

asked 2 days ago in Databases by arnabdana123 (6 points) | 8 views

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deadlock in databases
my question is isn’t wait wound and wait die deadlock prevention algo so how can we say that they are deadlock avoidance and how they can cause more aborts than needed?

asked 6 days ago in Databases by abcd9982 (8 points) | 4 views

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Normalization Self doubt
R = {Student ID, Last Name, First Name, Course ID, Course Section, Course Name, Grade, Professor Last Name, Professor First Name, Bldg, Office #, Semester} with following functional dependencies FD1 = Student ID --> Last Name, First Name FD2 ... , Prof_FName, Bldg, Office# CONVERTING IT TO 2NF IM GETTING THREE TABLES BUT ANSWER IS GIVEN AS 4 TABLES. PLEASE HELP ME.

asked Jun 24 in Databases by Sowmya tatavarthi (6 points) | 7 views

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transactions
a) S with no dirty read then S is cascadeless rollback but may not be strict recoverable b) S with no dirty read then S is recoverable but may not be cascadeless rollback c) S with no dirty read then S is conflict serializable schedule d) S with no dirty read then S is strict recoverable

asked Jun 24 in Databases by abcd9982 (8 points) | 42 views

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made_easy_test_series

asked Jun 24 in Databases by abcd9982 (8 points) | 12 views

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#DBMS #Normalisation
1.In case of lossy decomposition,when tables are merged then will newly created table contain either spurious tuples(extra tuples) or some tuples are removed from original table? 2.How the data is lost when newly created table contains some spurious table? According to me data should not be loss as it contains spurious tuples( extra info). P.s plz correct me if im

answered Jun 22 in Databases by Nikhil_dhama (87 points) | 19 views

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Transactions
R1(X),w2(X),R3(X),W1(X),W3(X). Is this scedsche is view serializable?

asked Jun 21 in Databases by G Shaheena (10 points) | 6 views

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Files and indexing
A file contain 100 blocks each with 10 records. The file is sorted contiguously on disk. The sort key is 5 bytes long and block pointer is 4 bytes and a record pointer is 5 bytes. A dense one-level index is built on this file How small can this index be in terms of number of bytes??

asked Jun 21 in Databases by G Shaheena (10 points) | 6 views

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Relational Algebra
NOTE: * denotes primary key; f denotes foreign key Que: Consider the above schema and give relational algebra query for the following 1. Find no. of students who have taken the courses taught by 'Joe' and not registered in any other courses, also they should ... place in PLACEID 100. 5. Find the details of student who has score GRADEPOINT A in all the course he/she is registered.

asked Jun 18 in Databases by Tris Ravi (11 points) | 3 views

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Relational table

asked Jun 18 in Databases by Tris Ravi (11 points) | 4 views

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Extended Entity Relationship Diagram
In a country, institutions are hiring employees for the position of either a junior scientist, senior scientist, or a lab assistant. We want to store the following data: 1. For each employee: First name, Date of Birth, position. 2. ... should not have redundant entity sets, attributes etc. If you need to make any assumptions, explain them in your answer.

asked Jun 18 in Databases by Tris Ravi (11 points) | 4 views

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Mae easy test series
Consider a schedule S: R1(A)R2(A)R3(A)R4(A)W1(B)W2(B)W3(B)W4(B). How many serializable schedules are there which are not conflict serializable?

asked Jun 15 in Databases by disneylover (8 points) | 16 views

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Self doubt on database
Wound wait and wait die are pessimistic deadloc avoidance algorithm and can cause more transaction aborts than needed. Is this statement true or false?

asked Jun 15 in Databases by disneylover (8 points) | 3 views

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MADE EASY TEST SERIES
Consider following Schedule S: S : W1(X) R2(X) W3(X) R4(X) W5(X) R6(X) W7(X) R8(X) W9(X) R10(X) The number of serial schedules view equivalent to Schedule S but not conflict equivalent to Schedule S ?

asked Jun 15 in Databases by disneylover (8 points) | 21 views

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Genral doubt
Could you please suggest me some resource for relational algebra and relational calculus in database?

asked Jun 12 in Databases by Shubham Aggarwal (8 points) | 5 views

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Normalization
R(ABCD) FD: { AB->C , C->AD} What is the highest normal form?

answered Jun 9 in Databases by prajjwalsingh_11 (16 points) | 23 views

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NIELIT- B/B+ tree
Identify the true statement from the given statements: Number of child pointers in a B/B+ tree node is always equal to number of keys in it plus one B/B+ tree is defined by a term minimum degree. And minimum degree depends on hard disk block size, key and address size (1) (1) and (2) (2) None of these

asked Jun 8 in Databases by Rishav Kumar Singh (6 points) | 4 views

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Self Doubt Database

asked Jun 7 in Databases by Abhipsa (27 points) | 10 views

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dbms minimal cover
F = {A → BC, B → C, A → B, AB → C}; When I find the minimal cover of this my fd is B->C, A->B, A->C correct me . given ans is- A->B,B->C

asked Jun 4 in Databases by Shubham Aggarwal (8 points) | 12 views

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self doubt in database normalization
Consider relation R(A,B,C,D) with functional dependencies: A -> B, C -> D, AD -> C, BC -> A Suppose we decompose R into Boyce-Codd Normal Form (BCNF). Which schemas will be in final decompositon.? CK-AC,AD,BC

asked Jun 4 in Databases by Shubham Aggarwal (8 points) | 6 views

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I want to know if A->C FD is valid then can we assume that A->B, B->C FD's will also exist.

asked May 23 in Databases by Bhav Esh Jagariya (6 points) | 12 views

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Made Easy Test Series
https://csedoubts.gateoverflow.in/?qa=blob&qa_blobid=12844912915578520272

asked May 21 in Databases by Rajeev-Dubey (6 points) | 12 views

+1 vote

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practice assignment
can i take an id input as 5372A623Z with number data type

answered May 15 in Databases by srestha (749 points) | 17 views

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B+ Tree Deletion

asked May 7 in Databases by James Bond (6 points) | 6 views

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DBMS Self doubt Indexing
Can any one give an example of clustered vs non clustered index ?

asked May 3 in Databases by Shivateja MST (127 points) | 6 views

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DBMS Indexing Ace Quesns
Database consists of 30000 records and each record length is 100 bytes.Consider block size=1024 bytes.Find the number of searches required without primary index if search key field value=9 bytes and block pointer=6 bytes. log 30000 (base 2) log 3000 (base 2) log 4 (base 2) log 3045 (base 2) Anyone please clarify.

asked May 3 in Databases by Shivateja MST (127 points) | 17 views

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DBMS_Ace_Quesns
How many clustered indexes a table can have? Any Can’t say Depends on columns in the table none of the above Anyone please clarify.

asked May 3 in Databases by Shivateja MST (127 points) | 7 views

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Madeeasy workbook of chapter Relational algebra
Consider the following relational schema adjacency(x,y) used to store edges of the graph. Which of the following statement not possible to represent constant length of relational algebra? (A) Retrieve vertices with self loop in graph ... whose indegree "0". (D) Retrieve vertices which are reachable two edge path length from given vertex.

asked May 2 in Databases by Priyanshi9 (6 points) | 6 views

+1 vote

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GATE2020-CS-36 Video Solution
Consider a relational table $R$ that is in $3NF$, but not in BCNF. Which one of the following statements is TRUE? $R$ has a nontrivial functional dependency $X \rightarrow A$, where $X$ is not a superkey and $A$ is a prime attribute. $R$ has a ... a non-prime attribute and $X$ is a proper subset of some key A cell in $R$ holds a set instead of an atomic value.

answered Apr 30 in Databases by amitkhurana512 (187 points) | 11 views

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DBMS Queries 3
A schedule S is having 3 transactions and each transaction is having two different data items and a blind Write A' statement is in all the three transactions. With the above information can you say whether the schedule is serializable ... serial schedules are there serializable and is equivalent to only two serial schedule detailed schedule is needed Anyone please clarify.

asked Apr 29 in Databases by Shivateja MST (127 points) | 18 views

+1 vote

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GATE2020-CS-14 Video Solution
Which one of the following is used to represent the supporting many-one relationships of a weak entity set in an entity-relationship diagram? Diamonds with double/bold border Rectangles with double/bold border Ovals with double/bold border Ovals that contain underlined identifiers

answered Apr 29 in Databases by amitkhurana512 (187 points) | 14 views

+1 vote

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GATE2020-CS-13 Video Solution
Consider a relational database containing the following schemas. $\begin{array}{c} \text{Catalogue} \end{array} $ ... WHERE pno = P4' GROUP BY pno) ; The number of rows returned by the above SQL query is $4$ $5$ $0$ $2$

answered Apr 29 in Databases by amitkhurana512 (187 points) | 10 views

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madeeasy workbook new question
order p is between 2 to p child pointer can store in root node and between [p] to p child can store in other 2 nodes of B tree index . Btree index.how many maximum level of index required to store 300 distict keys in order 5 B tree index?

asked Apr 28 in Databases by Chandrabhan Vishwa 1 (7 points) | 7 views

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SELF DOUBT(DATABASE4-B+TREES)
Suppose the order of a leaf in a B+ tree is p. the what is the minimum number of (key,record) pair that can be there in the leaf?

asked Apr 28 in Databases by Doraemon (115 points) | 5 views

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SELF DOUBT(DBMS3)
Q1>Do we consider lock upgradation by default by using 2PL? Q2>Consevative 2PL doesnot gurantee recoverability.right? please answer.

asked Apr 28 in Databases by Doraemon (115 points) | 4 views

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#DBMS #sql #workbook
Consider the following database Works(Ename,comp_name,sex,salary) and the sql query Select w1.Ename from works w1,(select avg(sal) as avg_sal ,comp_name from works where sex ='Male's group by comp_name)w2 Where w1.comp_name=w2.comp_name and w1. ... of their company d)retrieves names of all male employees who earn more than average salary of all male employees of their companey

asked Apr 28 in Databases by Jitendra2704 (6 points) | 5 views

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SELF DOUBT(DBMS2)
1>Relational Algebra is not having the same power as relational calculus unless it is safe relational calculus. Is this true and why?

asked Apr 28 in Databases by Doraemon (115 points) | 15 views

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SELF DOUBT(DBMS 1)
1>What is the associativity and precedence of operators in the relational algebra. Like what should be the associativity in expressions like A-B-C . and precedence in operations like A-B(natural join)C.

asked Apr 28 in Databases by Doraemon (115 points) | 5 views

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sql navathe page-272 example
SELECT Lname, Fname FROM EMPLOYEE WHERE NOT EXISTS ( SELECT * FROM WORKS_ON B WHERE ( B.Pno IN ( SELECT Pnumber FROM PROJECT WHERE Dnum=5 ) AND NOT EXISTS ( SELECT * FROM WORKS_ON C WHERE C.Essn=Ssn AND C.Pno=B.Pno ))); can anybody explain step ... dept 5? because for me i m getting all the employees who are working in at least one project under dept 5...pls pls help.

asked Apr 28 in Databases by debasree88 (14 points) | 7 views

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DBMS Queries
Which of the following statements is false? Every dominant entity is a strong entity. Specialization is done when more than one domain constraint is required on an attribute based on the entity type. A relationship type can be related to another relationship type. A weak entity will not have primary key on its own. Anyone please clarify.

asked Apr 27 in Databases by Shivateja MST (127 points) | 8 views

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