Initial commit: GovAI 政务AI平台

server/migrations/011_knowledge_chunks.sql

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+-- 知识库分片与向量检索支持
+-- 需要 pgvector 扩展: CREATE EXTENSION IF NOT EXISTS vector;
+
+CREATE EXTENSION IF NOT EXISTS vector;
+
+-- 知识文档分片表（每篇文档切分为多个 chunk，每个 chunk 存储 embedding 向量）
+CREATE TABLE IF NOT EXISTS knowledge_chunks (
+    id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
+    kb_id UUID NOT NULL REFERENCES knowledge_bases(id) ON DELETE CASCADE,
+    doc_id UUID NOT NULL REFERENCES knowledge_documents(id) ON DELETE CASCADE,
+    chunk_index INTEGER NOT NULL DEFAULT 0,
+    content TEXT NOT NULL,
+    char_count INTEGER NOT NULL DEFAULT 0,
+    embedding vector(1024),  -- 向量维度 1024（适配 text-embedding-v3）
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW()
+);
+
+-- 索引
+CREATE INDEX IF NOT EXISTS idx_knowledge_chunks_kb_id ON knowledge_chunks(kb_id);
+CREATE INDEX IF NOT EXISTS idx_knowledge_chunks_doc_id ON knowledge_chunks(doc_id);
+
+-- HNSW 向量索引（余弦距离）
+CREATE INDEX IF NOT EXISTS idx_knowledge_chunks_embedding ON knowledge_chunks
+    USING hnsw (embedding vector_cosine_ops)
+    WITH (m = 16, ef_construction = 64);
+
+-- 在 knowledge_documents 表添加 chunk_count 字段
+ALTER TABLE knowledge_documents ADD COLUMN IF NOT EXISTS chunk_count INTEGER DEFAULT 0;