Explain database design and consistency
Overview
This question evaluates proficiency in database design and consistency concepts, covering competencies such as data modeling, datastore selection, partitioning and indexing strategies, consistency semantics, operational trade-offs, validation and testing, and privacy/compliance considerations.
UiPath
Sep 6, 2025, 12:00 AM
Software Engineer
Technical Screen
System Design
0
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System Design (Technical Screen): Database Portion of a Project
Provide a structured description of the database component of a real project you owned. Keep your answer concrete, covering design choices, rationale, and outcomes.
What to Cover
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Business and performance goals
- Product context, user journeys, SLOs/SLAs (latency, availability), data retention, compliance/PII, multi-tenancy.
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Data model and access patterns
- Core entities, relationships, item sizes, cardinality; top read/write queries and their frequencies; pagination and filters.
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Datastore selection
- Chosen datastore(s) (e.g., DynamoDB, Postgres, Elasticsearch), why they fit, and why alternatives were not chosen.
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Partitioning and indexing strategy
- Partition and sort keys; sharding; GSIs/LSIs; projected attributes; TTL; hot key mitigation.
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Consistency settings and semantics
- Precisely define consistency (e.g., strong vs. eventual, read-after-write, monotonic reads, transactional/ACID scope). Explain implications for read and write paths and user-visible behavior.
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Trade-off evaluation
- How you balanced cost, latency, throughput, availability, durability, and operational complexity.
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Completion and validation
- What you delivered, how you load/scale tested, correctness checks, shadow/canary, and success metrics.
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Lessons learned
- Pitfalls, edge cases, what you would do differently.
Solution
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