diff --git a/backend-node/src/routes/companyManagementRoutes.ts b/backend-node/src/routes/companyManagementRoutes.ts
index a2e4a85c..630a3234 100644
--- a/backend-node/src/routes/companyManagementRoutes.ts
+++ b/backend-node/src/routes/companyManagementRoutes.ts
@@ -3,10 +3,9 @@ import { authenticateToken } from "../middleware/authMiddleware";
 import { AuthenticatedRequest } from "../types/auth";
 import { logger } from "../utils/logger";
 import { FileSystemManager } from "../utils/fileSystemManager";
-import { PrismaClient } from "@prisma/client";
+import { query, queryOne } from "../database/db";
 
 const router = express.Router();
-const prisma = new PrismaClient();
 
 // 모든 라우트에 인증 미들웨어 적용
 router.use(authenticateToken);
@@ -29,9 +28,10 @@ router.delete(
       });
 
       // 1. 회사 존재 확인
-      const existingCompany = await prisma.company_mng.findUnique({
-        where: { company_code: companyCode },
-      });
+      const existingCompany = await queryOne<any>(
+        `SELECT * FROM company_mng WHERE company_code = $1`,
+        [companyCode]
+      );
 
       if (!existingCompany) {
         res.status(404).json({
@@ -58,12 +58,10 @@ router.delete(
       }
 
       // 3. 데이터베이스에서 회사 삭제 (soft delete)
-      await prisma.company_mng.update({
-        where: { company_code: companyCode },
-        data: {
-          status: "deleted",
-        },
-      });
+      await query(
+        `UPDATE company_mng SET status = 'deleted' WHERE company_code = $1`,
+        [companyCode]
+      );
 
       logger.info("회사 삭제 완료", {
         companyCode,
diff --git a/backend-node/src/routes/ddlRoutes.ts b/backend-node/src/routes/ddlRoutes.ts
index f32ae586..ef80ede5 100644
--- a/backend-node/src/routes/ddlRoutes.ts
+++ b/backend-node/src/routes/ddlRoutes.ts
@@ -10,6 +10,7 @@ import {
   validateDDLPermission,
 } from "../middleware/superAdminMiddleware";
 import { authenticateToken } from "../middleware/authMiddleware";
+import { query } from "../database/db";
 
 const router = express.Router();
 
@@ -180,11 +181,7 @@ router.get("/info", authenticateToken, requireSuperAdmin, (req, res) => {
 router.get("/health", authenticateToken, async (req, res) => {
   try {
     // 기본적인 데이터베이스 연결 테스트
-    const { PrismaClient } = await import("@prisma/client");
-    const prisma = new PrismaClient();
-
-    await prisma.$queryRaw`SELECT 1`;
-    await prisma.$disconnect();
+    await query("SELECT 1");
 
     res.json({
       success: true,
diff --git a/backend-node/src/services/multiConnectionQueryService.ts b/backend-node/src/services/multiConnectionQueryService.ts
index 0751dfef..45e77500 100644
--- a/backend-node/src/services/multiConnectionQueryService.ts
+++ b/backend-node/src/services/multiConnectionQueryService.ts
@@ -8,7 +8,7 @@ import { ExternalDbConnectionService } from "./externalDbConnectionService";
 import { TableManagementService } from "./tableManagementService";
 import { ExternalDbConnection, ApiResponse } from "../types/externalDbTypes";
 import { ColumnTypeInfo, TableInfo } from "../types/tableManagement";
-import prisma from "../config/database";
+import { query } from "../database/db";
 import { logger } from "../utils/logger";
 
 // 🔧 Prisma 클라이언트 중복 생성 방지 - 기존 인스턴스 재사용
@@ -1002,7 +1002,7 @@ export class MultiConnectionQueryService {
             queryParams.push(...Object.values(conditions));
           }
 
-          return await prisma.$queryRawUnsafe(query, ...queryParams);
+          return await query(query, queryParams);
 
         case "insert":
           if (!data) throw new Error("INSERT 작업에는 데이터가 필요합니다.");
@@ -1019,11 +1019,10 @@ export class MultiConnectionQueryService {
             RETURNING *
           `;
 
-          const insertResult = await prisma.$queryRawUnsafe(
-            insertQuery,
-            ...insertValues
-          );
-          return Array.isArray(insertResult) ? insertResult[0] : insertResult;
+          const insertResult = await query(insertQuery, insertValues);
+          return Array.isArray(insertResult) && insertResult.length > 0
+            ? insertResult[0]
+            : insertResult;
 
         case "update":
           if (!data) throw new Error("UPDATE 작업에는 데이터가 필요합니다.");
@@ -1052,7 +1051,7 @@ export class MultiConnectionQueryService {
             ...Object.values(data),
             ...Object.values(conditions),
           ];
-          return await prisma.$queryRawUnsafe(updateQuery, ...updateParams);
+          return await query(updateQuery, updateParams);
 
         case "delete":
           if (!conditions)
@@ -1068,10 +1067,7 @@ export class MultiConnectionQueryService {
             RETURNING *
           `;
 
-          return await prisma.$queryRawUnsafe(
-            deleteQuery,
-            ...Object.values(conditions)
-          );
+          return await query(deleteQuery, Object.values(conditions));
 
         default:
           throw new Error(`지원하지 않는 작업입니다: ${operation}`);