Recent questions tagged databases / GATE Overflow for GATE CSE

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211

Database ER model
Consider the following relation (capitalized letters are attributes and lower letters are values). X: From the given FDs find the dependencies that seems to apply on X and identify a possible key (Candidate key) for X. A→C,D→E,C→A,E→B E→A,C→B,B→D,B→A

Consider the following relation (capitalized letters are attributes and lower letters are values).X:From the given FDs find the dependencies that seems to apply on X and ...

Ashutosh_17

433 views

Ashutosh_17 asked Apr 13, 2023

1 votes

2 answers

212

Database ER model
An ER diagram is having two strong entities E1 and E2. The relationship between the entities ‘R’ is having partial participation from E1 side and total participation from E2 side with 1:1 cardinality. The entities E1 and E2 are having one multivalued attribute each. How many numbers of relations are required to represent the ER model into the relational model?

An ER diagram is having two strong entities E1 and E2. The relationship between the entities ‘R’ is having partial participation from E1 side and total participation ...

Ashutosh_17

976 views

Ashutosh_17 asked Apr 13, 2023

0 votes

1 answer

213

Barc cse 2023 online exam
Which of the following are true a. A relational table can have atmost one foreign key b. The main purpose of foreign key is to optimize the queries by query optimizer.

Which of the following are truea. A relational table can have atmost one foreign keyb. The main purpose of foreign key is to optimize the queries by query optimizer.

gaddalakonda_ganesh

286 views

gaddalakonda_ganesh asked Apr 10, 2023

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1 answer

214

Kotidis I., First Exercise Pack 2021-2022.
Consider an extendible hash index, each bucket of which holds N entries. What is the probability that an overflowed bucket needs to be dealt with recursively? “Dealt with recursively” means that all of this bucket’s records are moved to one of the two new buckets that will be created.

Consider an extendible hash index, each bucket of which holds N entries. What is the probability that an overflowed bucket needs to be dealt with recursively? “Dealt wi...

juli

310 views

juli asked Apr 2, 2023

0 votes

1 answer

215

Database: Relational Algebra
Let R be a relation of degree 5 then the total number of projections possible on R is ___?

Let R be a relation of degree 5 then the total number of projections possible on R is ___?

Ashutosh_17

903 views

Ashutosh_17 asked Mar 30, 2023

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0 answers

216

Subject : Databse Topic: 2pl locking protocol..... If the given schedule is allowed under any 2pl( basic 2pl,strict or rigorous) then it is also allowed in conflict serializble , so if the schedule which is allowed in conflict serializable then also we can say it will be allowed in 2pl?

Ashutosh_17

311 views

Ashutosh_17 asked Mar 28, 2023

2 votes

1 answer

217

GO Classes 2023 | IIITH Mock Test 1 | Question: 17
Consider the following ER diagram : borrower mapping cardinality is many-to-many. While converting the ER diagram into a relational DBMS model, the relationship set borrower is converted into a relation borrower(cust_id, loan_id, ... , what is the primary key of borrower ? cust_id loan_id (cust_id, loan_id) (cust_id, loan_id, access_date)

Consider the following ER diagram :“borrower” mapping cardinality is many-to-many. While converting the ER diagram into a relational DBMS model, the relationship set ...

GO Classes

742 views

GO Classes asked Mar 26, 2023

1 votes

1 answer

218

GO Classes 2023 | IIITH Mock Test 1 | Question: 18
Consider the following schema: ... have reserved a blue AND a white boat. The names of sailors who have reserved neither a blue nor a white boat. Empty set.

Consider the following schema:$$\begin{array} {l} \text{Sailors}(\; \underline{\textit{sid: } \textsf{integer}}, \textit{ sname: } \textsf{string}, \textit{ rating: } \te...

GO Classes

620 views

GO Classes asked Mar 26, 2023

1 votes

1 answer

219

GO Classes 2023 | IIITH Mock Test 1 | Question: 19
Assume by "Serializability", we mean "Conflict Serializability". For the given schedule, which of the following is TRUE? $\text{T}_1$ $\text{T}_2$ $\text{T}_3$ $\text{T}_4$ Read(A) Read(A) Read(A) Write(B) Write(A) Read ... $\text{T}_2, \text{T}_3, \text{T}_1, \text{T}_4$

Assume by "Serializability", we mean "Conflict Serializability".For the given schedule, which of the following is TRUE?$\text{T}_1$$\text{T}_2$$\text{T}_3$$\text{T}_4$ ...

GO Classes

615 views

GO Classes asked Mar 26, 2023

2 votes

1 answer

220

GO Classes 2023 | IIITH Mock Test 1 | Question: 46
Consider a relation schema $\mathrm{R}$ with attributes $(\mathrm{X}, \mathrm{Y}, \mathrm{Z}, \mathrm{U}, \mathrm{V}, \mathrm{W})$ and the functional dependency set $\mathrm{F}$ that holds on $\mathrm{R}:$ ... . Decomposition is dependency preserving. $\text{P}$ is in $3 \mathrm{NF}$. $\mathrm{S}$ is in $3 \mathrm{NF}$.

Consider a relation schema $\mathrm{R}$ with attributes $(\mathrm{X}, \mathrm{Y}, \mathrm{Z}, \mathrm{U}, \mathrm{V}, \mathrm{W})$ and the functional dependency set $\mat...

GO Classes

846 views

GO Classes asked Mar 26, 2023

1 votes

1 answer

221

GO Classes 2023 | IIITH Mock Test 1 | Question: 47
Consider the following relations and query. $ \begin{gathered} \textsf{r(A, B, C)}\\ \textsf{s(A, B, C)}\\ \sigma_{\textsf{A>C}}([(\textsf{r} \cup \text{s) - (r - s)] - (s - r))} \end{gathered} $ Which of the following is ... $\sigma_{\textsf{A>C}}(\text{r} \cap \textsf{s})$

Consider the following relations and query.$$\begin{gathered}\textsf{r(A, B, C)}\\\textsf{s(A, B, C)}\\\sigma_{\textsf{A>C}}([(\textsf{r} \cup \text{s) - (r - s)] - (s - ...

GO Classes

497 views

GO Classes asked Mar 26, 2023

1 votes

1 answer

222

GO Classes 2023 | IIITH Mock Test 1 | Question: 48
A simple way to detect a state of deadlock is to construct a wait-for graph. One node is created in the graph for each transaction that is currently executing in the schedule. Whenever a transaction $\text{T}_i$ is waiting to ... for, the directed edge is dropped from the waiting-for graph. Given the graph below, which is/are deadlock free?

A simple way to detect a state of deadlock is to construct a wait-for graph. One node is created in the graph for each transaction that is currently executing in the sche...

GO Classes

533 views

GO Classes asked Mar 26, 2023

0 votes

1 answer

223

#dbms #normalisation
2NF , 3NF, BCNF decomposition allowed if lossless and dependency preserving , both conditions must preserve. Otherwise given decomposition wrong for normal forms. Is this statement correct????

2NF , 3NF, BCNF decomposition allowed if lossless and dependency preserving , both conditions must preserve. Otherwise given decomposition wrong for normal forms. Is this...

chinmay_rajpurohit

660 views

chinmay_rajpurohit asked Mar 2, 2023

0 votes

0 answers

224

Ace workbook dbms

gaddalakonda_ganesh

316 views

gaddalakonda_ganesh asked Feb 28, 2023

0 votes

2 answers

225

When is a group of attributes prime?
Given the candidate keys CD and DE and the functional dependency AB->CDE. Is CDE considered prime because all attributes (C, D and E) are prime? Or is it non-prime because CDE is not found in a candidate key as a whole? Therefore, my question is if a group of prime attributes is also prime due to its attributes or it has to be part of a candidate key as well.

Given the candidate keys CD and DE and the functional dependency AB->CDE. Is CDE considered prime because all attributes (C, D and E) are prime? Or is it non-prime becaus...

Mira67

715 views

Mira67 asked Feb 20, 2023

13 votes

5 answers

226

GATE CSE 2023 | Question: 6
Which one of the options given below refers to the degree (or arity) of a relation in relational database systems? Number of attributes of its relation schema. Number of tuples stored in the relation. Number of entries in the relation. Number of distinct domains of its relation schema.

Which one of the options given below refers to the degree (or arity) of a relation in relational database systems?Number of attributes of its relation schema.Number of tu...

admin

8.7k views

admin asked Feb 15, 2023

9 votes

2 answers

227

GATE CSE 2023 | Question: 51
Consider the following table named $\text{Student}$ in a relational database. The primary key of this table is $\text{rollNum}.$ $\text{Student}$ ... . SELECT * FROM Student WHERE gender = 'F' AND marks > 65; The number of rows returned by the query is ___________.

Consider the following table named $\text{Student}$ in a relational database. The primary key of this table is $\text{rollNum}.$$\text{Student}$$\begin{array}{|c|l|c|c|}\...

admin

7.5k views

admin asked Feb 15, 2023

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