Consolidate data access control backoffice updates

src/main/java/com/cloudhandson/vpdbackoffice/service/StructuredDataService.java

@@ -60,10 +60,27 @@ public class StructuredDataService {
       }
 
       List<Map<String, Object>> rows = jdbcTemplate.queryForList(
-          "SELECT * FROM " + OWNER + "." + table.tableName() + " WHERE ROWNUM <= ?", ROW_LIMIT);
+          previewSql(table), ROW_LIMIT);
       return new StructuredDataPreview(table, columns, rows, ROW_LIMIT);
     } catch (DataAccessException exception) {
       throw new AppException("정형 데이터를 조회할 수 없습니다. POC_2 조회 권한과 대상 테이블 상태를 확인하세요.");
     }
   }
+
+  /**
+   * The table is selected from a closed application whitelist, so the query
+   * text remains fixed and no request value can become a SQL identifier.
+   */
+  private String previewSql(StructuredDataTable table) {
+    return switch (table.key()) {
+      case "customers" -> "SELECT * FROM POC_2.KB_CUSTOMERS WHERE ROWNUM <= ?";
+      case "products" -> "SELECT * FROM POC_2.KB_PRODUCTS WHERE ROWNUM <= ?";
+      case "contracts" -> "SELECT * FROM POC_2.KB_CONTRACTS WHERE ROWNUM <= ?";
+      case "coverages" -> "SELECT * FROM POC_2.KB_COVERAGES WHERE ROWNUM <= ?";
+      case "claims" -> "SELECT * FROM POC_2.KB_CLAIMS WHERE ROWNUM <= ?";
+      case "external-holdings" -> "SELECT * FROM POC_2.KB_EXTERNAL_HOLDINGS WHERE ROWNUM <= ?";
+      case "stakeholders" -> "SELECT * FROM POC_2.KB_STAKEHOLDERS WHERE ROWNUM <= ?";
+      default -> throw new AppException("선택할 수 없는 정형 데이터 테이블입니다.");
+    };
+  }
 }