Design an audit system using Low-Level Design principles?
This LLD question requires creating a detailed class diagram and interaction flow for a system that tracks changes and maintains compliance records.
Why Interviewers Ask This
Audit systems require strict data integrity and traceability. This tests your ability to design robust, immutable data structures and handle concurrent access securely.
How to Answer This Question
Define entities: User, Action, Timestamp, AuditLog. Discuss immutability of logs. Handle concurrency with locking or versioning. Ensure read-only access for auditors. Consider scalability for large volumes of logs.
Key Points to Cover
- Immutable log structure
- Entity relationships
- Concurrency control
- Access control policies
Sample Answer
An audit system needs immutable logs recording user actions. I would design classes for User, Action, and AuditEntry. Each Entry includes a timestamp, user ID, action type, and data snapshot. Logs should be append-only t…
Common Mistakes to Avoid
- Allowing log modification
- Poor handling of concurrent writes
- Ignoring scalability needs
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