feat: 订单明细增加商品冗余字段，保存完整商品信息

src/main/java/com/example/building/entity/OrderItem.java

@@ -26,6 +26,11 @@ public class OrderItem {
      */
     private String productId;
 
+    /**
+     * 分类ID(冗余)
+     */
+    private String categoryId;
+
     /**
      * 商品名称(冗余)
      */
@@ -41,11 +46,36 @@ public class OrderItem {
      */
     private String unit;
 
+    /**
+     * 成本价(冗余)
+     */
+    private BigDecimal costPrice;
+
     /**
      * 销售单价(当时标价)
      */
     private BigDecimal price;
 
+    /**
+     * 商品图片URL(冗余)
+     */
+    private String imageUrl;
+
+    /**
+     * 商品条码(冗余)
+     */
+    private String barcode;
+
+    /**
+     * 库存预警阈值(冗余)
+     */
+    private Integer stockAlert;
+
+    /**
+     * 商品描述(冗余)
+     */
+    private String description;
+
     /**
      * 数量
      */

src/main/java/com/example/building/service/impl/OrderServiceImpl.java

@@ -102,9 +102,15 @@ public class OrderServiceImpl implements OrderService {
             item.setItemId(UUID.randomUUID().toString());
             item.setOrderId(order.getOrderId());
             item.setProductId(product.getProductId());
+            item.setCategoryId(product.getCategoryId());
             item.setProductName(product.getName());
             item.setProductSpec(product.getSpec());
             item.setUnit(product.getUnit());
+            item.setCostPrice(product.getCostPrice());
+            item.setImageUrl(product.getImageUrl());
+            item.setBarcode(product.getBarcode());
+            item.setStockAlert(product.getStockAlert());
+            item.setDescription(product.getDescription());
             item.setPrice(price);
             item.setQuantity(itemDTO.getQuantity());
             item.setSubtotal(subtotal);
@@ -347,9 +353,15 @@ public class OrderServiceImpl implements OrderService {
             item.setItemId(UUID.randomUUID().toString());
             item.setOrderId(orderId);
             item.setProductId(product.getProductId());
+            item.setCategoryId(product.getCategoryId());
             item.setProductName(product.getName());
             item.setProductSpec(product.getSpec());
             item.setUnit(product.getUnit());
+            item.setCostPrice(product.getCostPrice());
+            item.setImageUrl(product.getImageUrl());
+            item.setBarcode(product.getBarcode());
+            item.setStockAlert(product.getStockAlert());
+            item.setDescription(product.getDescription());
             item.setPrice(price);
             item.setQuantity(itemDTO.getQuantity());
             item.setSubtotal(subtotal);

src/main/resources/db/migration/V10__add_order_item_product_fields.sql

@@ -0,0 +1,7 @@
+-- 订单明细表增加商品冗余字段
+ALTER TABLE order_items ADD COLUMN IF NOT EXISTS category_id VARCHAR(36);
+ALTER TABLE order_items ADD COLUMN IF NOT EXISTS cost_price DECIMAL(10,2);
+ALTER TABLE order_items ADD COLUMN IF NOT EXISTS image_url VARCHAR(500);
+ALTER TABLE order_items ADD COLUMN IF NOT EXISTS barcode VARCHAR(50);
+ALTER TABLE order_items ADD COLUMN IF NOT EXISTS stock_alert INTEGER;
+ALTER TABLE order_items ADD COLUMN IF NOT EXISTS description TEXT;