Which data type for distance rounded to the nearest mile?
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
When storing distance rounded to the nearest whole mile, an integer data type is the optimal choice:
ALTER TABLE travel_logs ADD COLUMN distance_miles INT NOT NULL;
### Choosing the Exact Integer Type:
SMALLINT(-32,768 to 32,767 or 0 to 65,535 unsigned): Ideal for domestic road trips and regional commutes (takes only 2 bytes).INT/INTEGER(up to ~2.14 billion, 4 bytes): Safe default for global flights or astronomical distances.DECIMAL(8, 2)/NUMERIC: If requirements ever change to support fractional miles (e.g.14.75miles), switch to exact fixed-point decimals rather than floating-pointFLOAT/DOUBLEto prevent binary rounding inaccuracies.
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.