GATE CS 2017 Set 2 — Question 19
Go beyond PYQs with Success TrackerAI-powered personalised practice and doubt support. Unlimited practice on eligible plans; AI usage limits apply.NAT+1 / -0MediumKeys (Super, Candidate, Foreign)Relational ModelDatabases
Databases → Relational Model → Keys (Super, Candidate, Foreign)
Last updated
Question
Consider the following tables T1 and T2.
In table T1, P is the primary key and Q is the foreign key referencing R in table T2 with on-delete cascade and on-update cascade. In table T2, R is the primary key and S is the foreign key referencing P in table T1 with on-delete set NULL and on-update cascade. In order to delete record from table T1, the number of additional records that need to be deleted from table T1 is ________.
| T1 | T2 | |||
|---|---|---|---|---|
| P | Q | R | S | |
| 2 | 2 | 2 | 2 | |
| 3 | 8 | 8 | 3 | |
| 7 | 3 | 3 | 2 | |
| 5 | 8 | 9 | 7 | |
| 6 | 9 | 5 | 7 | |
| 8 | 5 | 7 | 2 | |
| 9 | 8 |
Correct answer
0 to 0
Solution
1.Deleting record from table T1 means the primary key value is removed.
2.Table T2 has a foreign key S referencing T1.**P** with the action on-delete set NULL. The record in T2 with is . Upon deletion of in T1, this record in T2 is updated to .
3.No record is deleted from table T2.
4.Table T1 has a foreign key Q referencing T2.**R** with the action on-delete cascade. Since no record was deleted from T2, no cascading deletions are triggered in T1.
5.Therefore, no additional records are deleted from T1. The answer is 0.
Continue learning with Success Tracker
A step still unclear? Work through it with support
Use Success Tracker to ask about the reasoning, then try another GATE CS question to check your understanding.
AI-powered practice· Unlimited practice on eligible plans
- PYQs with solutions
- Attempt available previous-year questions, then compare your reasoning with the worked solution. Coverage varies by stream.
- Practice that adapts
- Choose a topic, work on weaker areas and bookmark questions to revisit. Your attempts feed your progress tracking.
- AI doubt support
- Ask follow-up questions about a step or concept while practising, instead of stopping at the final answer.
Unlimited practice is available on eligible plans. Free practice and AI usage have limits; check the current plan allowances before choosing.
This page stays readable without an account. AI responses can be wrong; check them against the solution and source material.
More questions on Relational Model
2026 Set 2 Q15In the context of DBMS, consider the two sets T and S given below. | T | S | |---|---| | I:…2026 Set 2 Q20Consider concurrent execution of two transactions and in a DBMS, both of which access a…2026 Set 1 Q30Let and be the attributes of a relation in a relational schema. Let…2026 Set 1 Q31In the context of relational database normalization, which of the following statements is/are true?2026 Set 2 Q42In the context of schema normalization in relational DBMS, consider a set F of functional…