diff --git a/backend/src/main/java/com/linhelp/common/api/ApiResponse.java b/backend/src/main/java/com/linhelp/common/api/ApiResponse.java
new file mode 100644
index 0000000..e3887e4
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/api/ApiResponse.java
@@ -0,0 +1,52 @@
+package com.linhelp.common.api;
+
+public class ApiResponse<T> {
+    private int code;
+    private String message;
+    private T data;
+
+    public ApiResponse() {
+    }
+
+    public ApiResponse(int code, String message, T data) {
+        this.code = code;
+        this.message = message;
+        this.data = data;
+    }
+
+    public static <T> ApiResponse<T> ok(T data) {
+        return new ApiResponse<T>(0, "ok", data);
+    }
+
+    public static ApiResponse<Void> ok() {
+        return new ApiResponse<Void>(0, "ok", null);
+    }
+
+    public static ApiResponse<Void> fail(int code, String message) {
+        return new ApiResponse<Void>(code, message, null);
+    }
+
+    public int getCode() {
+        return code;
+    }
+
+    public void setCode(int code) {
+        this.code = code;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+
+    public T getData() {
+        return data;
+    }
+
+    public void setData(T data) {
+        this.data = data;
+    }
+}
diff --git a/backend/src/main/java/com/linhelp/common/api/PageResponse.java b/backend/src/main/java/com/linhelp/common/api/PageResponse.java
new file mode 100644
index 0000000..8686cc3
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/api/PageResponse.java
@@ -0,0 +1,52 @@
+package com.linhelp.common.api;
+
+import java.util.List;
+
+public class PageResponse<T> {
+    private long total;
+    private long pageNo;
+    private long pageSize;
+    private List<T> records;
+
+    public PageResponse() {
+    }
+
+    public PageResponse(long total, long pageNo, long pageSize, List<T> records) {
+        this.total = total;
+        this.pageNo = pageNo;
+        this.pageSize = pageSize;
+        this.records = records;
+    }
+
+    public long getTotal() {
+        return total;
+    }
+
+    public void setTotal(long total) {
+        this.total = total;
+    }
+
+    public long getPageNo() {
+        return pageNo;
+    }
+
+    public void setPageNo(long pageNo) {
+        this.pageNo = pageNo;
+    }
+
+    public long getPageSize() {
+        return pageSize;
+    }
+
+    public void setPageSize(long pageSize) {
+        this.pageSize = pageSize;
+    }
+
+    public List<T> getRecords() {
+        return records;
+    }
+
+    public void setRecords(List<T> records) {
+        this.records = records;
+    }
+}
diff --git a/backend/src/main/java/com/linhelp/common/enums/DeliveryMethod.java b/backend/src/main/java/com/linhelp/common/enums/DeliveryMethod.java
new file mode 100644
index 0000000..a5ba98c
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/enums/DeliveryMethod.java
@@ -0,0 +1,7 @@
+package com.linhelp.common.enums;
+
+public enum DeliveryMethod {
+    IMMEDIATE,
+    SCHEDULED,
+    SELF_PICKUP
+}
diff --git a/backend/src/main/java/com/linhelp/common/enums/DeliveryTaskStatus.java b/backend/src/main/java/com/linhelp/common/enums/DeliveryTaskStatus.java
new file mode 100644
index 0000000..0f73aa0
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/enums/DeliveryTaskStatus.java
@@ -0,0 +1,11 @@
+package com.linhelp.common.enums;
+
+public enum DeliveryTaskStatus {
+    ASSIGNED,
+    ACCEPTED,
+    DELIVERING,
+    DELIVERED,
+    EXCEPTION,
+    COMPLETED,
+    CANCELED
+}
diff --git a/backend/src/main/java/com/linhelp/common/enums/ExpressOrderStatus.java b/backend/src/main/java/com/linhelp/common/enums/ExpressOrderStatus.java
new file mode 100644
index 0000000..3a34546
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/enums/ExpressOrderStatus.java
@@ -0,0 +1,34 @@
+package com.linhelp.common.enums;
+
+import java.util.Collections;
+import java.util.EnumMap;
+import java.util.EnumSet;
+import java.util.Map;
+import java.util.Set;
+
+public enum ExpressOrderStatus {
+    PENDING_CONFIRM,
+    PENDING_PICKUP,
+    PICKING_UP,
+    DELIVERING,
+    DELIVERED,
+    COMPLETED,
+    CANCELED;
+
+    private static final Map<ExpressOrderStatus, Set<ExpressOrderStatus>> TRANSITIONS;
+
+    static {
+        Map<ExpressOrderStatus, Set<ExpressOrderStatus>> transitions = new EnumMap<ExpressOrderStatus, Set<ExpressOrderStatus>>(ExpressOrderStatus.class);
+        transitions.put(PENDING_CONFIRM, EnumSet.of(PENDING_PICKUP, CANCELED));
+        transitions.put(PENDING_PICKUP, EnumSet.of(PICKING_UP, CANCELED));
+        transitions.put(PICKING_UP, EnumSet.of(DELIVERING, CANCELED));
+        transitions.put(DELIVERING, EnumSet.of(DELIVERED, CANCELED));
+        transitions.put(DELIVERED, EnumSet.of(COMPLETED));
+        TRANSITIONS = Collections.unmodifiableMap(transitions);
+    }
+
+    public boolean canMoveTo(ExpressOrderStatus target) {
+        Set<ExpressOrderStatus> targets = TRANSITIONS.get(this);
+        return targets != null && targets.contains(target);
+    }
+}
diff --git a/backend/src/main/java/com/linhelp/common/enums/GoodsOrderStatus.java b/backend/src/main/java/com/linhelp/common/enums/GoodsOrderStatus.java
new file mode 100644
index 0000000..e1da8ac
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/enums/GoodsOrderStatus.java
@@ -0,0 +1,34 @@
+package com.linhelp.common.enums;
+
+import java.util.Collections;
+import java.util.EnumMap;
+import java.util.EnumSet;
+import java.util.Map;
+import java.util.Set;
+
+public enum GoodsOrderStatus {
+    PENDING_CONFIRM,
+    PREPARING,
+    PENDING_DELIVERY,
+    PENDING_PICKUP,
+    DELIVERING,
+    COMPLETED,
+    CANCELED;
+
+    private static final Map<GoodsOrderStatus, Set<GoodsOrderStatus>> TRANSITIONS;
+
+    static {
+        Map<GoodsOrderStatus, Set<GoodsOrderStatus>> transitions = new EnumMap<GoodsOrderStatus, Set<GoodsOrderStatus>>(GoodsOrderStatus.class);
+        transitions.put(PENDING_CONFIRM, EnumSet.of(PREPARING, CANCELED));
+        transitions.put(PREPARING, EnumSet.of(PENDING_DELIVERY, PENDING_PICKUP, CANCELED));
+        transitions.put(PENDING_DELIVERY, EnumSet.of(DELIVERING, CANCELED));
+        transitions.put(PENDING_PICKUP, EnumSet.of(COMPLETED, CANCELED));
+        transitions.put(DELIVERING, EnumSet.of(COMPLETED, CANCELED));
+        TRANSITIONS = Collections.unmodifiableMap(transitions);
+    }
+
+    public boolean canMoveTo(GoodsOrderStatus target) {
+        Set<GoodsOrderStatus> targets = TRANSITIONS.get(this);
+        return targets != null && targets.contains(target);
+    }
+}
diff --git a/backend/src/main/java/com/linhelp/common/enums/GroupBuyOrderStatus.java b/backend/src/main/java/com/linhelp/common/enums/GroupBuyOrderStatus.java
new file mode 100644
index 0000000..f34adb1
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/enums/GroupBuyOrderStatus.java
@@ -0,0 +1,11 @@
+package com.linhelp.common.enums;
+
+public enum GroupBuyOrderStatus {
+    PENDING_CONFIRM,
+    CONFIRMED,
+    PENDING_DELIVERY,
+    PENDING_PICKUP,
+    DELIVERING,
+    COMPLETED,
+    CANCELED
+}
diff --git a/backend/src/main/java/com/linhelp/common/enums/OfflinePayStatus.java b/backend/src/main/java/com/linhelp/common/enums/OfflinePayStatus.java
new file mode 100644
index 0000000..6e31a48
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/enums/OfflinePayStatus.java
@@ -0,0 +1,8 @@
+package com.linhelp.common.enums;
+
+public enum OfflinePayStatus {
+    UNPAID,
+    PAID,
+    FREE,
+    EXCEPTION
+}
diff --git a/backend/src/main/java/com/linhelp/common/enums/SecondGoodsStatus.java b/backend/src/main/java/com/linhelp/common/enums/SecondGoodsStatus.java
new file mode 100644
index 0000000..2ddc32c
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/enums/SecondGoodsStatus.java
@@ -0,0 +1,9 @@
+package com.linhelp.common.enums;
+
+public enum SecondGoodsStatus {
+    PENDING_REVIEW,
+    PUBLISHED,
+    REJECTED,
+    OFF_SHELF,
+    SOLD
+}
diff --git a/backend/src/main/java/com/linhelp/common/exception/BizException.java b/backend/src/main/java/com/linhelp/common/exception/BizException.java
new file mode 100644
index 0000000..194a3e1
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/exception/BizException.java
@@ -0,0 +1,18 @@
+package com.linhelp.common.exception;
+
+public class BizException extends RuntimeException {
+    private final int code;
+
+    public BizException(String message) {
+        this(400, message);
+    }
+
+    public BizException(int code, String message) {
+        super(message);
+        this.code = code;
+    }
+
+    public int getCode() {
+        return code;
+    }
+}
diff --git a/backend/src/main/java/com/linhelp/common/exception/GlobalExceptionHandler.java b/backend/src/main/java/com/linhelp/common/exception/GlobalExceptionHandler.java
new file mode 100644
index 0000000..ef0c74f
--- /dev/null
+++ b/backend/src/main/java/com/linhelp/common/exception/GlobalExceptionHandler.java
@@ -0,0 +1,26 @@
+package com.linhelp.common.exception;
+
+import com.linhelp.common.api.ApiResponse;
+import org.springframework.validation.BindException;
+import org.springframework.web.bind.MethodArgumentNotValidException;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    @ExceptionHandler(BizException.class)
+    public ApiResponse<Void> handleBizException(BizException exception) {
+        return ApiResponse.fail(exception.getCode(), exception.getMessage());
+    }
+
+    @ExceptionHandler({MethodArgumentNotValidException.class, BindException.class})
+    public ApiResponse<Void> handleValidationException(Exception exception) {
+        return ApiResponse.fail(422, "请求参数不正确");
+    }
+
+    @ExceptionHandler(Exception.class)
+    public ApiResponse<Void> handleException(Exception exception) {
+        return ApiResponse.fail(500, "系统繁忙，请稍后再试");
+    }
+}
diff --git a/backend/src/main/resources/db/migration/V1__init_schema.sql b/backend/src/main/resources/db/migration/V1__init_schema.sql
new file mode 100644
index 0000000..cca8d3d
--- /dev/null
+++ b/backend/src/main/resources/db/migration/V1__init_schema.sql
@@ -0,0 +1,458 @@
+CREATE TABLE tenant (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  name VARCHAR(80) NOT NULL,
+  status VARCHAR(24) NOT NULL DEFAULT 'ENABLED',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0
+);
+
+CREATE TABLE community (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  name VARCHAR(80) NOT NULL,
+  address VARCHAR(255) NOT NULL,
+  contact_name VARCHAR(40),
+  contact_phone VARCHAR(32),
+  status VARCHAR(24) NOT NULL DEFAULT 'ENABLED',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_community_tenant (tenant_id)
+);
+
+CREATE TABLE community_module_config (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  module_code VARCHAR(40) NOT NULL,
+  enabled TINYINT NOT NULL DEFAULT 1,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  UNIQUE KEY uk_community_module (community_id, module_code)
+);
+
+CREATE TABLE app_user (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  openid VARCHAR(80),
+  nickname VARCHAR(80),
+  avatar_url VARCHAR(255),
+  phone VARCHAR(32),
+  status VARCHAR(24) NOT NULL DEFAULT 'ENABLED',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_app_user_openid (openid),
+  INDEX idx_app_user_community (community_id)
+);
+
+CREATE TABLE user_address (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  user_id BIGINT NOT NULL,
+  contact_name VARCHAR(40) NOT NULL,
+  phone VARCHAR(32) NOT NULL,
+  building VARCHAR(80) NOT NULL,
+  room VARCHAR(80) NOT NULL,
+  detail VARCHAR(255),
+  is_default TINYINT NOT NULL DEFAULT 0,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_user_address_user (user_id)
+);
+
+CREATE TABLE sys_role (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  code VARCHAR(40) NOT NULL UNIQUE,
+  name VARCHAR(80) NOT NULL
+);
+
+CREATE TABLE user_role (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  user_id BIGINT NOT NULL,
+  role_code VARCHAR(40) NOT NULL,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT,
+  merchant_id BIGINT,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  UNIQUE KEY uk_user_role_scope (user_id, role_code, tenant_id, community_id, merchant_id)
+);
+
+CREATE TABLE merchant (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  name VARCHAR(100) NOT NULL,
+  merchant_type VARCHAR(40) NOT NULL,
+  contact_name VARCHAR(40),
+  contact_phone VARCHAR(32),
+  status VARCHAR(24) NOT NULL DEFAULT 'ENABLED',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_merchant_community (community_id)
+);
+
+CREATE TABLE product_category (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  name VARCHAR(80) NOT NULL,
+  sort_no INT NOT NULL DEFAULT 0,
+  enabled TINYINT NOT NULL DEFAULT 1,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0
+);
+
+CREATE TABLE product (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  merchant_id BIGINT NOT NULL,
+  category_id BIGINT NOT NULL,
+  name VARCHAR(120) NOT NULL,
+  cover_url VARCHAR(255),
+  description TEXT,
+  unit_name VARCHAR(20) NOT NULL DEFAULT '件',
+  status VARCHAR(24) NOT NULL DEFAULT 'OFF_SHELF',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_product_category (category_id),
+  INDEX idx_product_merchant (merchant_id)
+);
+
+CREATE TABLE product_sku (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  product_id BIGINT NOT NULL,
+  sku_name VARCHAR(80) NOT NULL,
+  price_cent INT NOT NULL,
+  origin_price_cent INT,
+  stock INT NOT NULL DEFAULT 0,
+  enabled TINYINT NOT NULL DEFAULT 1,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_product_sku_product (product_id)
+);
+
+CREATE TABLE goods_order (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  order_no VARCHAR(40) NOT NULL UNIQUE,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  user_id BIGINT NOT NULL,
+  merchant_id BIGINT NOT NULL,
+  address_id BIGINT,
+  delivery_method VARCHAR(24) NOT NULL,
+  scheduled_time DATETIME,
+  status VARCHAR(32) NOT NULL,
+  offline_pay_status VARCHAR(24) NOT NULL DEFAULT 'UNPAID',
+  total_amount_cent INT NOT NULL,
+  remark VARCHAR(255),
+  cancel_reason VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_goods_order_user (user_id),
+  INDEX idx_goods_order_status (community_id, status)
+);
+
+CREATE TABLE goods_order_item (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  order_id BIGINT NOT NULL,
+  product_id BIGINT NOT NULL,
+  sku_id BIGINT NOT NULL,
+  product_name VARCHAR(120) NOT NULL,
+  sku_name VARCHAR(80) NOT NULL,
+  quantity INT NOT NULL,
+  price_cent INT NOT NULL,
+  amount_cent INT NOT NULL,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_goods_order_item_order (order_id)
+);
+
+CREATE TABLE stock_log (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  product_id BIGINT NOT NULL,
+  sku_id BIGINT NOT NULL,
+  change_quantity INT NOT NULL,
+  before_stock INT NOT NULL,
+  after_stock INT NOT NULL,
+  biz_type VARCHAR(32) NOT NULL,
+  biz_order_id BIGINT,
+  note VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_stock_log_sku (sku_id)
+);
+
+CREATE TABLE order_log (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  biz_type VARCHAR(32) NOT NULL,
+  biz_order_id BIGINT NOT NULL,
+  from_status VARCHAR(32),
+  to_status VARCHAR(32),
+  action VARCHAR(64) NOT NULL,
+  operator_id BIGINT,
+  note VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_order_log_biz (biz_type, biz_order_id)
+);
+
+CREATE TABLE express_order (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  order_no VARCHAR(40) NOT NULL UNIQUE,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  user_id BIGINT NOT NULL,
+  address_id BIGINT NOT NULL,
+  express_company VARCHAR(80) NOT NULL,
+  pickup_code VARCHAR(120) NOT NULL,
+  pickup_address VARCHAR(255) NOT NULL,
+  package_count INT NOT NULL,
+  service_fee_cent INT NOT NULL,
+  phone VARCHAR(32) NOT NULL,
+  image_url VARCHAR(255),
+  status VARCHAR(32) NOT NULL,
+  offline_pay_status VARCHAR(24) NOT NULL DEFAULT 'UNPAID',
+  remark VARCHAR(255),
+  cancel_reason VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_express_order_status (community_id, status)
+);
+
+CREATE TABLE express_log (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  express_order_id BIGINT NOT NULL,
+  from_status VARCHAR(32),
+  to_status VARCHAR(32),
+  action VARCHAR(64) NOT NULL,
+  operator_id BIGINT,
+  note VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_express_log_order (express_order_id)
+);
+
+CREATE TABLE group_buy (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  merchant_id BIGINT NOT NULL,
+  title VARCHAR(120) NOT NULL,
+  cover_url VARCHAR(255),
+  description TEXT,
+  price_cent INT NOT NULL,
+  origin_price_cent INT,
+  stock INT NOT NULL,
+  deadline_at DATETIME NOT NULL,
+  expected_delivery_at DATETIME,
+  status VARCHAR(32) NOT NULL DEFAULT 'NOT_STARTED',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_group_buy_status (community_id, status)
+);
+
+CREATE TABLE group_buy_order (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  order_no VARCHAR(40) NOT NULL UNIQUE,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  group_buy_id BIGINT NOT NULL,
+  user_id BIGINT NOT NULL,
+  address_id BIGINT,
+  delivery_method VARCHAR(24) NOT NULL,
+  quantity INT NOT NULL,
+  amount_cent INT NOT NULL,
+  status VARCHAR(32) NOT NULL,
+  offline_pay_status VARCHAR(24) NOT NULL DEFAULT 'UNPAID',
+  remark VARCHAR(255),
+  cancel_reason VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_group_buy_order_activity (group_buy_id),
+  INDEX idx_group_buy_order_user (user_id)
+);
+
+CREATE TABLE delivery_user (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  user_id BIGINT NOT NULL,
+  name VARCHAR(40) NOT NULL,
+  phone VARCHAR(32) NOT NULL,
+  status VARCHAR(24) NOT NULL DEFAULT 'ENABLED',
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0
+);
+
+CREATE TABLE delivery_order (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  biz_type VARCHAR(32) NOT NULL,
+  biz_order_id BIGINT NOT NULL,
+  delivery_user_id BIGINT NOT NULL,
+  status VARCHAR(32) NOT NULL,
+  delivered_photo_url VARCHAR(255),
+  exception_type VARCHAR(64),
+  exception_note VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  UNIQUE KEY uk_delivery_biz_order (biz_type, biz_order_id),
+  INDEX idx_delivery_user_status (delivery_user_id, status)
+);
+
+CREATE TABLE delivery_log (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  delivery_order_id BIGINT NOT NULL,
+  from_status VARCHAR(32),
+  to_status VARCHAR(32),
+  action VARCHAR(64) NOT NULL,
+  operator_id BIGINT,
+  note VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_delivery_log_order (delivery_order_id)
+);
+
+CREATE TABLE second_goods (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  user_id BIGINT NOT NULL,
+  title VARCHAR(120) NOT NULL,
+  price_cent INT NOT NULL,
+  description TEXT,
+  category VARCHAR(40) NOT NULL,
+  contact_phone VARCHAR(32) NOT NULL,
+  trade_method VARCHAR(32) NOT NULL,
+  status VARCHAR(32) NOT NULL,
+  reject_reason VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_second_goods_status (community_id, status),
+  INDEX idx_second_goods_user (user_id)
+);
+
+CREATE TABLE second_goods_img (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  second_goods_id BIGINT NOT NULL,
+  image_url VARCHAR(255) NOT NULL,
+  sort_no INT NOT NULL DEFAULT 0,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_second_goods_img_goods (second_goods_id)
+);
+
+CREATE TABLE second_goods_comment (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  second_goods_id BIGINT NOT NULL,
+  user_id BIGINT NOT NULL,
+  content VARCHAR(500) NOT NULL,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_second_goods_comment_goods (second_goods_id)
+);
+
+CREATE TABLE notice (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  title VARCHAR(120) NOT NULL,
+  content TEXT NOT NULL,
+  category VARCHAR(40) NOT NULL,
+  pinned TINYINT NOT NULL DEFAULT 0,
+  status VARCHAR(24) NOT NULL DEFAULT 'DRAFT',
+  published_at DATETIME,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_notice_status (community_id, status, pinned)
+);
+
+CREATE TABLE banner (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  title VARCHAR(120) NOT NULL,
+  image_url VARCHAR(255) NOT NULL,
+  link_type VARCHAR(32),
+  link_value VARCHAR(255),
+  sort_no INT NOT NULL DEFAULT 0,
+  enabled TINYINT NOT NULL DEFAULT 1,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_banner_community (community_id, enabled)
+);
+
+CREATE TABLE feedback (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  user_id BIGINT NOT NULL,
+  biz_type VARCHAR(32),
+  biz_order_id BIGINT,
+  content VARCHAR(500) NOT NULL,
+  status VARCHAR(24) NOT NULL DEFAULT 'OPEN',
+  reply VARCHAR(500),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  deleted TINYINT NOT NULL DEFAULT 0,
+  INDEX idx_feedback_status (community_id, status)
+);
+
+CREATE TABLE payment_record (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  biz_type VARCHAR(32) NOT NULL,
+  biz_order_id BIGINT NOT NULL,
+  amount_cent INT NOT NULL,
+  pay_method VARCHAR(32) NOT NULL DEFAULT 'OFFLINE',
+  pay_status VARCHAR(24) NOT NULL,
+  paid_at DATETIME,
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_payment_biz (biz_type, biz_order_id)
+);
+
+CREATE TABLE refund_record (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  tenant_id BIGINT NOT NULL,
+  community_id BIGINT NOT NULL,
+  payment_record_id BIGINT,
+  biz_type VARCHAR(32) NOT NULL,
+  biz_order_id BIGINT NOT NULL,
+  amount_cent INT NOT NULL,
+  refund_status VARCHAR(24) NOT NULL,
+  reason VARCHAR(255),
+  created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  INDEX idx_refund_biz (biz_type, biz_order_id)
+);
diff --git a/backend/src/test/java/com/linhelp/common/enums/StatusTransitionTests.java b/backend/src/test/java/com/linhelp/common/enums/StatusTransitionTests.java
new file mode 100644
index 0000000..2a7098f
--- /dev/null
+++ b/backend/src/test/java/com/linhelp/common/enums/StatusTransitionTests.java
@@ -0,0 +1,25 @@
+package com.linhelp.common.enums;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class StatusTransitionTests {
+
+    @Test
+    void goodsOrderCanMoveFromPendingConfirmToPreparing() {
+        assertThat(GoodsOrderStatus.PENDING_CONFIRM.canMoveTo(GoodsOrderStatus.PREPARING)).isTrue();
+    }
+
+    @Test
+    void goodsOrderCannotMoveFromCompletedToDelivering() {
+        assertThat(GoodsOrderStatus.COMPLETED.canMoveTo(GoodsOrderStatus.DELIVERING)).isFalse();
+    }
+
+    @Test
+    void expressOrderCanMoveThroughPickupFlow() {
+        assertThat(ExpressOrderStatus.PENDING_CONFIRM.canMoveTo(ExpressOrderStatus.PENDING_PICKUP)).isTrue();
+        assertThat(ExpressOrderStatus.PENDING_PICKUP.canMoveTo(ExpressOrderStatus.PICKING_UP)).isTrue();
+        assertThat(ExpressOrderStatus.PICKING_UP.canMoveTo(ExpressOrderStatus.DELIVERING)).isTrue();
+    }
+}