databases

Work with databases from code: SQL queries, JDBC, connections, CRUD, and indexes, demonstrated with tested, copy-ready snippets.

Agentic RAG in Python: Hybrid Search, Reranking, and GraphRAG

Plain RAG works right up until real users show up: typed keywords miss, and questions that span two files come back half answered. Agentic RAG treats retrieval as a loop the system can steer, rewriting the query, blending keyword and vector search, reranking, and retrieving again. This post upgrades the LlamaIndex pipeline with real numbers for every step, so you tune with proof instead of vibes. One quick definition first, because “agentic” leans on an idea we have not properly ... Read More

FastAPI Capstone: Build, Test, and Ship a Real API

This FastAPI project is the capstone for Part 3: one small but real Application Programming Interface (API) that you build, test, containerize, gate behind CI, and deploy to a public URL. It is a bookmarks service (sign up, log in, save links, list them with pagination), the kind of thing you could actually put your name on and hand to an interviewer. “Code without tests is broken as designed.” Jacob Kaplan-Moss, Django co-creator Last Updated: July 2026 | Tested on: ... Read More

SQL Indexes, Query Plans, and Schema Design That Scales

SQL indexes are the single biggest lever you have for making a slow database query fast, and in this post you will watch one index turn a query from 72 milliseconds into 0.04 milliseconds on a one million row table. You will also learn to read EXPLAIN QUERY PLAN line by line, design a schema that stays fast as it grows, keep your data honest with transactions, and kill the N+1 query problem that quietly wrecks so many apps. “An ... Read More