feat: Prisma 완전 제거 완료 🎉

최종 작업:

1. config/database.ts 삭제:
   - Prisma 기반 database.ts 완전 제거
   - 더 이상 사용되지 않는 파일

2. referenceCacheService.ts 전환 (3개):
   - ✅ getTableRowCount: $queryRawUnsafe → query
   - ✅ cacheReferenceTable: $queryRawUnsafe → query
   - ✅ batchLookup: $queryRaw → query (ANY 연산자)

전체 완료:
- ✅ 모든 Prisma 호출 전환 완료
- ✅ PrismaClient import 완전 제거 (에러핸들러 제외)
- ✅ database.ts 삭제
- ✅ Raw Query 기반 시스템으로 완전 전환

최종 진행률: 54/54 (100%) 🎉

backend-node/src/config/database.ts

@@ -1,50 +0,0 @@
-import { PrismaClient } from "@prisma/client";
-import config from "./environment";
-
-// Prisma 클라이언트 생성 함수
-function createPrismaClient() {
-  return new PrismaClient({
-    datasources: {
-      db: {
-        url: config.databaseUrl,
-      },
-    },
-    log: config.debug ? ["query", "info", "warn", "error"] : ["error"],
-  });
-}
-
-// 단일 인스턴스 생성
-const prisma = createPrismaClient();
-
-// 데이터베이스 연결 테스트
-async function testConnection() {
-  try {
-    await prisma.$connect();
-  } catch (error) {
-    console.error("❌ 데이터베이스 연결 실패:", error);
-    process.exit(1);
-  }
-}
-
-// 애플리케이션 종료 시 연결 해제
-process.on("beforeExit", async () => {
-  await prisma.$disconnect();
-});
-
-process.on("SIGINT", async () => {
-  await prisma.$disconnect();
-  process.exit(0);
-});
-
-process.on("SIGTERM", async () => {
-  await prisma.$disconnect();
-  process.exit(0);
-});
-
-// 초기 연결 테스트 (개발 환경에서만)
-if (config.nodeEnv === "development") {
-  testConnection();
-}
-
-// 기본 내보내기
-export = prisma;

backend-node/src/services/referenceCacheService.ts

@@ -1,12 +1,10 @@
-import { PrismaClient } from "@prisma/client";
+import { query, queryOne } from "../database/db";
 import { logger } from "../utils/logger";
 import {
   BatchLookupRequest,
   BatchLookupResponse,
 } from "../types/tableManagement";
 
-const prisma = new PrismaClient();
-
 interface CacheEntry {
   data: Map<string, any>;
   expiry: number;
@@ -38,11 +36,12 @@ export class ReferenceCacheService {
    */
   private async getTableRowCount(tableName: string): Promise<number> {
     try {
-      const countResult = (await prisma.$queryRawUnsafe(`
-        SELECT COUNT(*) as count FROM ${tableName}
-      `)) as Array<{ count: bigint }>;
+      const countResult = await query<{ count: string }>(
+        `SELECT COUNT(*) as count FROM ${tableName}`,
+        []
+      );
 
-      return Number(countResult[0]?.count || 0);
+      return parseInt(countResult[0]?.count || "0", 10);
     } catch (error) {
       logger.error(`테이블 크기 조회 실패: ${tableName}`, error);
       return 0;
@@ -140,13 +139,14 @@ export class ReferenceCacheService {
       logger.info(`참조 테이블 캐싱 시작: ${tableName}`);
 
       // 데이터 조회
-      const data = (await prisma.$queryRawUnsafe(`
-        SELECT ${keyColumn} as key, ${displayColumn} as value 
-        FROM ${tableName}
-        WHERE ${keyColumn} IS NOT NULL 
-        AND ${displayColumn} IS NOT NULL
-        ORDER BY ${keyColumn}
-      `)) as Array<{ key: any; value: any }>;
+      const data = await query<{ key: any; value: any }>(
+        `SELECT ${keyColumn} as key, ${displayColumn} as value 
+         FROM ${tableName}
+         WHERE ${keyColumn} IS NOT NULL 
+         AND ${displayColumn} IS NOT NULL
+         ORDER BY ${keyColumn}`,
+        []
+      );
 
       const dataMap = new Map<string, any>();
       for (const row of data) {
@@ -301,11 +301,12 @@ export class ReferenceCacheService {
         const keys = missingRequests.map((req) => req.key);
         const displayColumn = missingRequests[0].displayColumn; // 같은 테이블이므로 동일
 
-        const data = (await prisma.$queryRaw`
-          SELECT key_column as key, ${displayColumn} as value 
-          FROM ${tableName}
-          WHERE key_column = ANY(${keys})
-        `) as Array<{ key: any; value: any }>;
+        const data = await query<{ key: any; value: any }>(
+          `SELECT key_column as key, ${displayColumn} as value 
+           FROM ${tableName}
+           WHERE key_column = ANY($1)`,
+          [keys]
+        );
 
         // 결과를 응답에 추가
         for (const row of data) {