add pg vector and embed

prisma/migrations/20250822104302_add_pgvector/migration.sql

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+-- Migration: Add pgvector support to icd_codes table
+
+-- Enable pgvector extension
+CREATE EXTENSION IF NOT EXISTS vector;
+
+-- Add embedding column with pgvector type
+ALTER TABLE "icd_codes" ADD COLUMN IF NOT EXISTS "embedding" vector(1536);
+
+-- Add metadata column for LangChain pgvector
+ALTER TABLE "icd_codes" ADD COLUMN IF NOT EXISTS "metadata" JSONB;
+
+-- Add content column for LangChain pgvector
+ALTER TABLE "icd_codes" ADD COLUMN IF NOT EXISTS "content" TEXT;
+
+-- Create ivfflat index for fast vector similarity search
+CREATE INDEX IF NOT EXISTS "icd_codes_embedding_idx" ON "icd_codes" 
+USING ivfflat (embedding vector_cosine_ops) WITH (lists = 100);
+
+-- Create index on metadata for fast JSON queries
+CREATE INDEX IF NOT EXISTS "icd_codes_metadata_idx" ON "icd_codes" USING GIN (metadata);
+
+-- Add comments for documentation
+COMMENT ON COLUMN "icd_codes"."embedding" IS 'Vector embedding for semantic search using pgvector (1536 dimensions)';
+COMMENT ON COLUMN "icd_codes"."metadata" IS 'JSON metadata for LangChain pgvector operations';
+COMMENT ON COLUMN "icd_codes"."content" IS 'Text content for LangChain pgvector operations';
+COMMENT ON INDEX "icd_codes_embedding_idx" IS 'IVFFlat index for fast cosine similarity search with 100 lists';
+COMMENT ON INDEX "icd_codes_metadata_idx" IS 'GIN index for fast JSON metadata queries';