diff --git a/backend-node/src/controllers/adminController.ts b/backend-node/src/controllers/adminController.ts
index 1a573834..9dea63b8 100644
--- a/backend-node/src/controllers/adminController.ts
+++ b/backend-node/src/controllers/adminController.ts
@@ -3563,19 +3563,21 @@ export async function getTableSchema(
 
     logger.info("테이블 스키마 조회", { tableName, companyCode });
 
-    // information_schema와 table_type_columns를 JOIN하여 컬럼 정보와 라벨 정보 함께 가져오기
-    // 회사별 라벨 우선, 없으면 공통(*) 라벨 사용
+    // information_schema와 table_type_columns를 JOIN하여 컬럼 정보 + 회사별 제약조건 함께 가져오기
+    // 회사별 설정 우선, 없으면 공통(*) 설정 사용
     const schemaQuery = `
       SELECT 
         ic.column_name,
         ic.data_type,
-        ic.is_nullable,
+        ic.is_nullable AS db_is_nullable,
         ic.column_default,
         ic.character_maximum_length,
         ic.numeric_precision,
         ic.numeric_scale,
         COALESCE(ttc_company.column_label, ttc_common.column_label) AS column_label,
-        COALESCE(ttc_company.display_order, ttc_common.display_order) AS display_order
+        COALESCE(ttc_company.display_order, ttc_common.display_order) AS display_order,
+        COALESCE(ttc_company.is_nullable, ttc_common.is_nullable) AS ttc_is_nullable,
+        COALESCE(ttc_company.is_unique, ttc_common.is_unique) AS ttc_is_unique
       FROM information_schema.columns ic
       LEFT JOIN table_type_columns ttc_common 
         ON ttc_common.table_name = ic.table_name 
@@ -3600,17 +3602,28 @@ export async function getTableSchema(
       return;
     }
 
-    // 컬럼 정보를 간단한 형태로 변환 (라벨 정보 포함)
-    const columnList = columns.map((col: any) => ({
-      name: col.column_name,
-      label: col.column_label || col.column_name, // 라벨이 없으면 컬럼명 사용
-      type: col.data_type,
-      nullable: col.is_nullable === "YES",
-      default: col.column_default,
-      maxLength: col.character_maximum_length,
-      precision: col.numeric_precision,
-      scale: col.numeric_scale,
-    }));
+    // 컬럼 정보를 간단한 형태로 변환 (회사별 제약조건 반영)
+    const columnList = columns.map((col: any) => {
+      // DB level nullable + 회사별 table_type_columns 제약조건 통합
+      // table_type_columns에서 is_nullable = 'N'이면 필수 (DB가 nullable이어도)
+      const dbNullable = col.db_is_nullable === "YES";
+      const ttcNotNull = col.ttc_is_nullable === "N";
+      const effectiveNullable = ttcNotNull ? false : dbNullable;
+
+      const ttcUnique = col.ttc_is_unique === "Y";
+
+      return {
+        name: col.column_name,
+        label: col.column_label || col.column_name,
+        type: col.data_type,
+        nullable: effectiveNullable,
+        unique: ttcUnique,
+        default: col.column_default,
+        maxLength: col.character_maximum_length,
+        precision: col.numeric_precision,
+        scale: col.numeric_scale,
+      };
+    });
 
     logger.info(`테이블 스키마 조회 성공: ${columnList.length}개 컬럼`);
 
diff --git a/backend-node/src/controllers/dataflowExecutionController.ts b/backend-node/src/controllers/dataflowExecutionController.ts
index 338fa628..71eb2211 100644
--- a/backend-node/src/controllers/dataflowExecutionController.ts
+++ b/backend-node/src/controllers/dataflowExecutionController.ts
@@ -8,6 +8,7 @@ import { Request, Response } from "express";
 import { AuthenticatedRequest } from "../types/auth";
 import { query } from "../database/db";
 import logger from "../utils/logger";
+import { TableManagementService } from "../services/tableManagementService";
 
 /**
  * 데이터 액션 실행
@@ -81,6 +82,19 @@ async function executeMainDatabaseAction(
       company_code: companyCode,
     };
 
+    // UNIQUE 제약조건 검증 (INSERT/UPDATE/UPSERT 전)
+    if (["insert", "update", "upsert"].includes(actionType.toLowerCase())) {
+      const tms = new TableManagementService();
+      const uniqueViolations = await tms.validateUniqueConstraints(
+        tableName,
+        dataWithCompany,
+        companyCode
+      );
+      if (uniqueViolations.length > 0) {
+        throw new Error(`중복된 값이 존재합니다: ${uniqueViolations.join(", ")}`);
+      }
+    }
+
     switch (actionType.toLowerCase()) {
       case "insert":
         return await executeInsert(tableName, dataWithCompany);
diff --git a/backend-node/src/controllers/dynamicFormController.ts b/backend-node/src/controllers/dynamicFormController.ts
index 4ba6013a..31c11638 100644
--- a/backend-node/src/controllers/dynamicFormController.ts
+++ b/backend-node/src/controllers/dynamicFormController.ts
@@ -1,6 +1,7 @@
 import { Response } from "express";
 import { dynamicFormService } from "../services/dynamicFormService";
 import { enhancedDynamicFormService } from "../services/enhancedDynamicFormService";
+import { TableManagementService } from "../services/tableManagementService";
 import { AuthenticatedRequest } from "../types/auth";
 import { formatPgError } from "../utils/pgErrorUtil";
 
@@ -48,6 +49,21 @@ export const saveFormData = async (
       formDataWithMeta.company_code = companyCode;
     }
 
+    // UNIQUE 제약조건 검증 (INSERT 전)
+    const tms = new TableManagementService();
+    const uniqueViolations = await tms.validateUniqueConstraints(
+      tableName,
+      formDataWithMeta,
+      companyCode || "*"
+    );
+    if (uniqueViolations.length > 0) {
+      res.status(400).json({
+        success: false,
+        message: `중복된 값이 존재합니다: ${uniqueViolations.join(", ")}`,
+      });
+      return;
+    }
+
     // 클라이언트 IP 주소 추출
     const ipAddress =
       req.ip ||
@@ -112,6 +128,21 @@ export const saveFormDataEnhanced = async (
       formDataWithMeta.company_code = companyCode;
     }
 
+    // UNIQUE 제약조건 검증 (INSERT 전)
+    const tmsEnhanced = new TableManagementService();
+    const uniqueViolations = await tmsEnhanced.validateUniqueConstraints(
+      tableName,
+      formDataWithMeta,
+      companyCode || "*"
+    );
+    if (uniqueViolations.length > 0) {
+      res.status(400).json({
+        success: false,
+        message: `중복된 값이 존재합니다: ${uniqueViolations.join(", ")}`,
+      });
+      return;
+    }
+
     // 개선된 서비스 사용
     const result = await enhancedDynamicFormService.saveFormData(
       screenId,
@@ -153,12 +184,28 @@ export const updateFormData = async (
     const formDataWithMeta = {
       ...data,
       updated_by: userId,
-      writer: data.writer || userId, // ✅ writer가 없으면 userId로 설정
+      writer: data.writer || userId,
       updated_at: new Date(),
     };
 
+    // UNIQUE 제약조건 검증 (UPDATE 시 자기 자신 제외)
+    const tmsUpdate = new TableManagementService();
+    const uniqueViolations = await tmsUpdate.validateUniqueConstraints(
+      tableName,
+      formDataWithMeta,
+      companyCode || "*",
+      id
+    );
+    if (uniqueViolations.length > 0) {
+      res.status(400).json({
+        success: false,
+        message: `중복된 값이 존재합니다: ${uniqueViolations.join(", ")}`,
+      });
+      return;
+    }
+
     const result = await dynamicFormService.updateFormData(
-      id, // parseInt 제거 - 문자열 ID 지원
+      id,
       tableName,
       formDataWithMeta
     );
@@ -209,11 +256,27 @@ export const updateFormDataPartial = async (
     const newDataWithMeta = {
       ...newData,
       updated_by: userId,
-      writer: newData.writer || userId, // ✅ writer가 없으면 userId로 설정
+      writer: newData.writer || userId,
     };
 
+    // UNIQUE 제약조건 검증 (부분 UPDATE 시 자기 자신 제외)
+    const tmsPartial = new TableManagementService();
+    const uniqueViolations = await tmsPartial.validateUniqueConstraints(
+      tableName,
+      newDataWithMeta,
+      companyCode || "*",
+      id
+    );
+    if (uniqueViolations.length > 0) {
+      res.status(400).json({
+        success: false,
+        message: `중복된 값이 존재합니다: ${uniqueViolations.join(", ")}`,
+      });
+      return;
+    }
+
     const result = await dynamicFormService.updateFormDataPartial(
-      id, // 🔧 parseInt 제거 - UUID 문자열도 지원
+      id,
       tableName,
       originalData,
       newDataWithMeta
diff --git a/backend-node/src/controllers/tableManagementController.ts b/backend-node/src/controllers/tableManagementController.ts
index 0c35fdbd..5087a1c9 100644
--- a/backend-node/src/controllers/tableManagementController.ts
+++ b/backend-node/src/controllers/tableManagementController.ts
@@ -2087,6 +2087,23 @@ export async function multiTableSave(
       return;
     }
 
+    // UNIQUE 제약조건 검증 (트랜잭션 전에)
+    const tmsMulti = new TableManagementService();
+    const uniqueViolations = await tmsMulti.validateUniqueConstraints(
+      mainTable.tableName,
+      mainData,
+      companyCode,
+      isUpdate ? mainData[mainTable.primaryKeyColumn] : undefined
+    );
+    if (uniqueViolations.length > 0) {
+      client.release();
+      res.status(400).json({
+        success: false,
+        message: `중복된 값이 존재합니다: ${uniqueViolations.join(", ")}`,
+      });
+      return;
+    }
+
     await client.query("BEGIN");
 
     // 1. 메인 테이블 저장
diff --git a/backend-node/src/middleware/errorHandler.ts b/backend-node/src/middleware/errorHandler.ts
index baa5ce38..b592ae2e 100644
--- a/backend-node/src/middleware/errorHandler.ts
+++ b/backend-node/src/middleware/errorHandler.ts
@@ -41,7 +41,18 @@ export const errorHandler = (
     // PostgreSQL 에러 코드 참조: https://www.postgresql.org/docs/current/errcodes-appendix.html
     if (pgError.code === "23505") {
       // unique_violation
-      error = new AppError("중복된 데이터가 존재합니다.", 400);
+      const constraint = pgError.constraint || "";
+      const tbl = pgError.table || "";
+      let col = "";
+      if (constraint && tbl) {
+        const prefix = `${tbl}_`;
+        const suffix = "_key";
+        if (constraint.startsWith(prefix) && constraint.endsWith(suffix)) {
+          col = constraint.slice(prefix.length, -suffix.length);
+        }
+      }
+      const detail = col ? ` [${col}]` : "";
+      error = new AppError(`중복된 데이터가 존재합니다.${detail}`, 400);
     } else if (pgError.code === "23503") {
       // foreign_key_violation
       error = new AppError("참조 무결성 제약 조건 위반입니다.", 400);
diff --git a/backend-node/src/routes/dataRoutes.ts b/backend-node/src/routes/dataRoutes.ts
index de83e720..c8ba23d8 100644
--- a/backend-node/src/routes/dataRoutes.ts
+++ b/backend-node/src/routes/dataRoutes.ts
@@ -5,6 +5,8 @@ import { multiTableExcelService, TableChainConfig } from "../services/multiTable
 import { authenticateToken } from "../middleware/authMiddleware";
 import { AuthenticatedRequest } from "../types/auth";
 import { auditLogService } from "../services/auditLogService";
+import { TableManagementService } from "../services/tableManagementService";
+import { formatPgError } from "../utils/pgErrorUtil";
 
 const router = express.Router();
 
@@ -950,6 +952,20 @@ router.post(
         console.log(`🏢 company_name 자동 추가: ${req.user.companyName}`);
       }
 
+      // UNIQUE 제약조건 검증
+      const tms = new TableManagementService();
+      const uniqueViolations = await tms.validateUniqueConstraints(
+        tableName,
+        enrichedData,
+        req.user?.companyCode || "*"
+      );
+      if (uniqueViolations.length > 0) {
+        return res.status(400).json({
+          success: false,
+          message: `중복된 값이 존재합니다: ${uniqueViolations.join(", ")}`,
+        });
+      }
+
       // 레코드 생성
       const result = await dataService.createRecord(tableName, enrichedData);
 
@@ -1019,6 +1035,21 @@ router.put(
 
       console.log(`✏️ 레코드 수정: ${tableName}/${id}`, data);
 
+      // UNIQUE 제약조건 검증 (자기 자신 제외)
+      const tmsUpdate = new TableManagementService();
+      const uniqueViolations = await tmsUpdate.validateUniqueConstraints(
+        tableName,
+        data,
+        req.user?.companyCode || "*",
+        String(id)
+      );
+      if (uniqueViolations.length > 0) {
+        return res.status(400).json({
+          success: false,
+          message: `중복된 값이 존재합니다: ${uniqueViolations.join(", ")}`,
+        });
+      }
+
       // 레코드 수정
       const result = await dataService.updateRecord(tableName, id, data);
 
diff --git a/backend-node/src/services/multiTableExcelService.ts b/backend-node/src/services/multiTableExcelService.ts
index d18f479b..7f9de79d 100644
--- a/backend-node/src/services/multiTableExcelService.ts
+++ b/backend-node/src/services/multiTableExcelService.ts
@@ -970,10 +970,11 @@ class MultiTableExcelService {
     const result = await pool.query(
       `SELECT
          c.column_name,
-         c.is_nullable,
+         c.is_nullable AS db_is_nullable,
          c.column_default,
          COALESCE(ttc.column_label, cl.column_label) AS column_label,
-         COALESCE(ttc.reference_table, cl.reference_table) AS reference_table
+         COALESCE(ttc.reference_table, cl.reference_table) AS reference_table,
+         COALESCE(ttc.is_nullable, cl.is_nullable) AS ttc_is_nullable
        FROM information_schema.columns c
        LEFT JOIN table_type_columns cl
          ON c.table_name = cl.table_name AND c.column_name = cl.column_name AND cl.company_code = '*'
@@ -991,13 +992,13 @@ class MultiTableExcelService {
       // 시스템 컬럼 제외
       if (MultiTableExcelService.SYSTEM_COLUMNS.has(colName)) continue;
 
-      // FK 컬럼 제외 (reference_table이 있는 컬럼 = 다른 테이블의 PK를 참조)
-      // 단, 비즈니스적으로 의미 있는 FK는 남길 수 있으므로,
-      // _id로 끝나면서 reference_table이 있는 경우만 제외
+      // FK 컬럼 제외
       if (row.reference_table && colName.endsWith("_id")) continue;
 
       const hasDefault = row.column_default !== null;
-      const isNullable = row.is_nullable === "YES";
+      const dbNullable = row.db_is_nullable === "YES";
+      const ttcNotNull = row.ttc_is_nullable === "N";
+      const isNullable = ttcNotNull ? false : dbNullable;
       const isRequired = !isNullable && !hasDefault;
 
       columns.push({
diff --git a/backend-node/src/utils/pgErrorUtil.ts b/backend-node/src/utils/pgErrorUtil.ts
index abec8f4e..3f7c56d3 100644
--- a/backend-node/src/utils/pgErrorUtil.ts
+++ b/backend-node/src/utils/pgErrorUtil.ts
@@ -37,8 +37,38 @@ export async function formatPgError(
       const detail = colName ? ` [${colName}]` : "";
       return `필수 입력값이 누락되었습니다.${detail}`;
     }
-    case "23505":
-      return "중복된 데이터가 존재합니다.";
+    case "23505": {
+      // unique_violation
+      const constraint = error.constraint || "";
+      const tblName = error.table || "";
+      // constraint 이름에서 컬럼명 추출 시도 (예: item_mst_item_code_key → item_code)
+      let colName = "";
+      if (constraint && tblName) {
+        const prefix = `${tblName}_`;
+        const suffix = "_key";
+        if (constraint.startsWith(prefix) && constraint.endsWith(suffix)) {
+          colName = constraint.slice(prefix.length, -suffix.length);
+        }
+      }
+      if (colName && tblName && companyCode) {
+        try {
+          const rows = await query(
+            `SELECT column_label FROM table_type_columns 
+             WHERE table_name = $1 AND column_name = $2 AND company_code = $3 
+             LIMIT 1`,
+            [tblName, colName, companyCode]
+          );
+          const label = rows[0]?.column_label;
+          if (label) {
+            return `중복된 데이터가 존재합니다: ${label}`;
+          }
+        } catch {
+          // 폴백
+        }
+      }
+      const detail = colName ? ` [${colName}]` : "";
+      return `중복된 데이터가 존재합니다.${detail}`;
+    }
     case "23503":
       return "참조 무결성 제약 조건 위반입니다.";
     default:
diff --git a/frontend/lib/registry/components/v2-table-list/TableListComponent.tsx b/frontend/lib/registry/components/v2-table-list/TableListComponent.tsx
index 4087be04..0ceb72fd 100644
--- a/frontend/lib/registry/components/v2-table-list/TableListComponent.tsx
+++ b/frontend/lib/registry/components/v2-table-list/TableListComponent.tsx
@@ -1061,19 +1061,22 @@ export const TableListComponent: React.FC<TableListComponentProps> = ({
         }
       }
 
-      // 백엔드 DISTINCT API로 전체 고유값 조회 (페이징과 무관하게 모든 값 반환)
-      try {
-        const { apiClient } = await import("@/lib/api/client");
-        const response = await apiClient.get(`/entity/${tableConfig.selectedTable}/distinct/${columnName}`);
+      // 카테고리/엔티티/코드 타입이 아닌 경우에만 DISTINCT API 사용
+      // (카테고리 등은 DISTINCT로 조회하면 코드만 반환되어 label이 없음)
+      if (!["category", "entity", "code"].includes(inputType)) {
+        try {
+          const { apiClient } = await import("@/lib/api/client");
+          const response = await apiClient.get(`/entity/${tableConfig.selectedTable}/distinct/${columnName}`);
 
-        if (response.data.success && response.data.data && response.data.data.length > 0) {
-          return response.data.data.map((item: any) => ({
-            value: String(item.value),
-            label: String(item.label),
-          }));
+          if (response.data.success && response.data.data && response.data.data.length > 0) {
+            return response.data.data.map((item: any) => ({
+              value: String(item.value),
+              label: String(item.label),
+            }));
+          }
+        } catch (error: any) {
+          // DISTINCT API 실패 시 현재 데이터 기반으로 fallback
         }
-      } catch (error: any) {
-        // DISTINCT API 실패 시 현재 데이터 기반으로 fallback
       }
 
       // fallback: 현재 로드된 데이터에서 고유 값 추출
diff --git a/frontend/lib/registry/components/v2-table-search-widget/TableSearchWidget.tsx b/frontend/lib/registry/components/v2-table-search-widget/TableSearchWidget.tsx
index 39e888ab..8799c835 100644
--- a/frontend/lib/registry/components/v2-table-search-widget/TableSearchWidget.tsx
+++ b/frontend/lib/registry/components/v2-table-search-widget/TableSearchWidget.tsx
@@ -467,14 +467,9 @@ export function TableSearchWidget({ component, screenId, onHeightChange }: Table
 
       if (hasNewOptions) {
         setSelectOptions((prev) => {
-          // 이미 로드된 옵션은 유지, 새로 로드된 옵션만 병합
-          const merged = { ...prev };
-          for (const [key, value] of Object.entries(loadedOptions)) {
-            if (!merged[key] || merged[key].length === 0) {
-              merged[key] = value;
-            }
-          }
-          return merged;
+          // 새로 로드된 옵션으로 항상 갱신 (카테고리 label 정보가 나중에 로드될 수 있으므로)
+          // 로드 실패한 컬럼의 기존 옵션은 유지
+          return { ...prev, ...loadedOptions };
         });
       }
     };