Does Using UUID as PK Hurt Index Performance?
Code Review Comment While building the Gift API at Kakao Tech Campus, I used UUIDs as member identifiers. My mentor left this comment in a code review: “Since you’re using UUID, you might want...
Junyoung Yang
Select-then-Update vs Single Update: What Matters More Than Performance
Problem While building the Gift API clone at Kakao Tech Campus, I needed to implement a product update API. In a JDBC environment, there were two main approaches: Method 1: Single Update Query ...
Building a RAG Pipeline to Reduce LLM Hallucination
Problem At PNU x Upstage DOCUMENT AI CHALLENGE, I developed “DocDoc,” an AI service for overseas medical teams. It was a chatbot that finds relevant papers and answers questions from medical profe...
Android Fragment Lifecycle and savedInstanceState Debugging
Problem Back in high school, I built a convenience app called “Dongcheon Alimi” for my classmates. It displayed timetables, meal info, announcements, and more. The screen layout was: 4 Fragmen...
Building a TCP/IP Socket Server for IoT Smart Lighting
Project Background I participated in the 1st Woosong University National SW Club Competition and built an IoT smart lighting system that automatically adjusts brightness based on ambient light lev...