Which is NOT TRUE about constraints?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of SQL & Databases conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
Any assertion claiming that constraints are optional in production or that constraints significantly slow down reads is false.
### Why Constraints Are Vital:
- Constraints preserve data integrity at the lowest physical database tier, preventing corrupted data even if application code contains bugs.
- Primary key and unique constraints automatically create underlying B-tree indexes, accelerating query performance rather than degrading it.
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.