APPENDIX: Quick Reference

(This appendix has the code snippets you'll actually copy-paste when building systems. Bookmark this page. You'll be back here constantly until this stuff becomes muscle memory.)

Common Code Patterns

1. Basic RAG Query

def rag_query(question, vector_db, llm):
    # Retrieve
    docs = vector_db.query(get_embedding(question), top_k=5)

    # Generate
    context = "\n".join([d['content'] for d in docs])
    prompt = f"Context: {context}\n\nQuestion: {question}\nAnswer:"
    answer = llm.generate(prompt)

    return answer

2. KG Entity Lookup

MATCH (e:Entity {name: $entity_name})
RETURN e, properties(e)

3. Hybrid Retrieval

# Get from both sources
kg_facts = graph_db.query(cypher_query)
rag_docs = vector_db.query(embedding)

# Fuse
context = format_kg(kg_facts) + format_docs(rag_docs)
answer = llm.generate(context + question)