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Recent questions tagged referential-integrity

3 votes

2 answers

1

Applied Test Series
Consider the following schema: Create table A(a1 int not null primary key, a2 int); Create table B(b1 int not null primary key, b2 int references A(a1) on delete cascade on update no action); Create table C(c1 int not null primary key, c2 int references ... number of tuples present in the relation B, and C after running the query Delete from A where a1 = 1; will be __________

LRU asked in Databases Nov 5, 2021

by LRU

433 views

15 votes

6 answers

2

GATE CSE 2021 Set 2 | Question: 6
Consider the following statements $S1$ and $S2$ about the relational data model: $S1$: A relation scheme can have at most one foreign key. $S2$: A foreign key in a relation scheme $R$ cannot be used to refer to tuples of $R.$ Which one of the following choices ... are true $S1$ is true and $S2$ is false $S1$ is false and $S2$ is true Both $S1$ and $S2$ are false

Arjun asked in Databases Feb 18, 2021

by Arjun

5.8k views

1 vote

2 answers

3

NIELIT Scientific Assistant A 2020 November: 97
Domain constraints, functional dependency and referential integrity are special forms of _______ Foreign key Primary key Assertion Referential constraint

gatecse asked in Databases Dec 9, 2020

221 views

2 votes

3 answers

4

UGC NET CSE | June 2019 | Part 2 | Question: 39
Following table has two attributes Employee_id and Manager_id, where Employee_id is a primary key and manager_id is a foreign key referencing Employee_id with on-delete cascade: ... $(35, 20)$ only $(35, 20)$ only $(40, 45)$ and $(25, 40)$ only

Arjun asked in Databases Jul 2, 2019

by Arjun

2.5k views

1 vote

1 answer

5

ER Model Self Doubt
How to represent referential integrity constraint in ER model? pls explain with diagram

aditi19 asked in Databases Jun 7, 2019

1.5k views

2 votes

3 answers

6

NIELIT 2018-49
The following table has two attributes $X$ and $Y$ where $X$ is the primary key and $Y$ is the foreign key referencing $X$ ... $(4,3)$ and $(6,4)$ $(2,4)$ and $(7,2)$ $(3,2)$ and $(9,5)$ $(3,4), (4,5)$ and $(6,4)$

Arjun asked in Databases Dec 7, 2018

by Arjun

2.9k views

0 votes

0 answers

7

Self-doubt [Foreign keys and Third Normal Form]
I've some elementary doubts regarding Foreign keys (referential integrity) : Can a foreign key consist of a collection of attributes - ie. can two or more columns collectively form a foreign key? If foreign key refers ... : Multiple candidate keys Composite candidate keys Overlapping candidate keys If possible, please provide an example. Thank You.!

Harsh Kumar asked in Databases Nov 19, 2018

734 views

0 votes

0 answers

8

Gate 2004 doubt on foreign keys
Referencing to this gate ques- https://gateoverflow.in/16095/gate2004_13-let-and-two-relation-schema-where-the-primary-key Let R1 (A, B, C) and R2 (D, E) be two relation schema, where the primary keys are shown underlined, and let C be a ... subtracting entities of D from C can still have null and other values(those were duplicate). So, how will it get empty set?

bts1jimin asked in Databases Sep 1, 2018

740 views

0 votes

2 answers

9

Test question
Consider the join of a relation R with a relation S. If R has 100 tuples and S has 9 tuples then the maximum and minimum sizes of the join respectively under referential integrity constraint: 9 and 0 9 and 9 9+100 and 0 9*100 and 9

Priyendu Mori asked in Databases Dec 31, 2017

by Priyendu Mori

371 views

2 votes

3 answers

10

DBMS :- Referential integrity constraints
select the correct statement from the following on referential integrity Select one: a. referential integrity constraints check whether the primary key, values are unique b. referential integrity constraints check whether an ... two relations in a schema d. referential integrity constraints are specified between entities having recursive relationship

rahul sharma 5 asked in Databases Dec 17, 2017

by rahul sharma 5

8.6k views

0 votes

1 answer

11

Referential Integrity
Consider the join of a relation R with a relation S. If R has 100 tuples and S has 9 tuples then the maximum and minimum sizes of the join respectively under referential integrity constraint:- (A) 9 and 0 (B) 9 and 9 (C) 9+100 and 0 (D) 9*100 and 9

ankitgupta.1729 asked in Databases Dec 16, 2017

by ankitgupta.1729

1.0k views

2 votes

1 answer

12

Self Doubt
Let R (ABCD) and S(DEF). D is the foreign key in R that references primary key in S. Which of the following will not violation? a. Insertion in R b. Insertion in S c. Deletion from R d. Deletion from S

Mk Utkarsh asked in Databases Dec 12, 2017

345 views

1 vote

1 answer

13

Recursive foreign key
Explain recursive foreign key with suitable example..

rishu_darkshadow asked in Programming Sep 29, 2017

by rishu_darkshadow

4.9k views

55 votes

6 answers

14

GATE CSE 2017 Set 2 | Question: 19
Consider the following tables $T1$ and $T2.$ ... delete record $\langle 3, 8 \rangle$ from the table $T1,$ the number of additional records that need to be deleted from table $T1$ is _______

Madhav asked in Databases Feb 14, 2017

by Madhav

14.9k views

1 vote

1 answer

15

Virtual Gate Test Series: Databases - Referential Integrity
We can convert any weak entity set to a strong entity set by simply adding appropriate attributes. Why, then, do we have weak entity sets at all? $1)$ We want to avoid the data duplication and consequent possible inconsistencies caused by duplicating the key of the strong ... : $A)1$ and $2$ $B)2$ and $3$ $C)1$ and $3$ $D)1,2$ and $3$

Purple asked in Databases Jan 19, 2017

by Purple

4.2k views

3 votes

2 answers

16

foreign key constraint
What is on delete no action,on delete cascade, on delete set null action?? explain through some eg??

Hira Thakur asked in Databases Nov 3, 2016

1.3k views

5 votes

2 answers

17

KISHALAY DAS asked in Databases Oct 19, 2016

by KISHALAY DAS

1.1k views

2 votes

1 answer

18

UGC NET CSE | September 2013 | Part 3 | Question: 24
____ constraints ensure that a value that appears in one relation for a given set of attributes also appears for a certain set of attributes in another relation. Logical Integrity Referential Integrity Domain Integrity Data Integrity

go_editor asked in Databases Jul 23, 2016

4.5k views

5 votes

2 answers

19

ISRO2009-72
Purpose of 'Foreign Key' in a table is to ensure Null Integrity Referential Integrity Domain Integrity Null and Domain Integrity

Anuanu asked in Databases May 30, 2016

by Anuanu

3.4k views

0 votes

0 answers

20

Navathe-Fundamentals of Database systems-basic SQL-sixth edition-4.7
Consider the LIBRARY relational database schema shown in the figure below .Choose the appropriate action (reject, cascade, set to NULL, set to default) for each referential integrity constraint, both for the deletion of a referenced tuple and for the update of primary key attribute value in a referenced tuple.Justify your choices

ibia asked in Databases Apr 2, 2016

by ibia

857 views

0 votes

0 answers

21

Navathe-sixth edition-4.5
Consider the database shown below ,Whose schema is also shown below .What are the referential integrity constraints that should hold on the schema ? Write appropriate $SQL$ $DDL$ ... Credit_hours Department PREREQUISITE Course_number Prerequisite_number SECTION Section_identifier Course_number Semester year Instructor GRADE_REPORT Student_number Section_identifier Grade

ibia asked in Databases Apr 1, 2016

by ibia

360 views

0 votes

1 answer

22

FOERIGN KEY
what is the advantage of keeping the Foreign Key null as we know if we make the Foreign Key null we cant reference it again so thats a disadvantage ......so there must be some advantage which outweighs this disadvantage so whats that advantage

Bhagirathi asked in Databases Feb 3, 2016

318 views

1 vote

3 answers

23

Relation between Intersection and natural inner join on common column
When , then the cost of computing is (A) the same as R S (B) greater the R S (C) less than R S (D) cannot say anything

Purple asked in Databases Jan 24, 2016

by Purple

1.4k views

0 votes

3 answers

24

if natural join is done then min and max no. of tuples if referential integrity is taken and not
R(ABC) S(BDE) F:A->B B ->C B->D D->E AND R HAS 100 TUPLES AND S HAS 200

uzumzki asked in Databases Aug 17, 2015

1.7k views

31 votes

2 answers

25

GATE CSE 1997 | Question: 6.10, ISRO2016-54
Let $R (a, b, c)$ and $S(d, e, f)$ be two relations in which $d$ is the foreign key of $S$ that refers to the primary key of $R$. Consider the following four operations $R$ and $S$ Insert into $R$ Insert ... Which of the following can cause violation of the referential integrity constraint above? Both I and IV Both II and III All of these None of these

Kathleen asked in Databases Sep 29, 2014

8.8k views

38 votes

2 answers

26

GATE CSE 2005 | Question: 76
The following table has two attributes $A$ and $C$ where $A$ is the primary key and $C$ is the foreign key referencing $A$ ... $(7, 2)$ $(5, 2), (7, 2)$ and $(9, 5)$ $(3, 4), (4, 3)$ and $(6, 4)$

Kathleen asked in Databases Sep 22, 2014

16.4k views

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