diff --git a/src/modules/masters/items/items.service.js b/src/modules/masters/items/items.service.js
index de05316..91d73f0 100644
--- a/src/modules/masters/items/items.service.js
+++ b/src/modules/masters/items/items.service.js
@@ -8,6 +8,13 @@ const ITEM_SERIES_CODE = 'ITEM';
 
 const SEARCH_FIELDS = ['item_code', 'item_name'];
 
+const SOFT_DELETE_TABLES = new Set([
+  'item_categories',
+  'item_subcategories',
+  'uom',
+  'brands',
+]);
+
 const normalizeString = (value) => {
   if (value === undefined || value === null) return value;
   const str = String(value).trim();
@@ -60,13 +67,26 @@ const normalizePayload = (payload, { isCreate = false } = {}) => {
 const assertReference = async (table, id, label, { requireActive = true } = {}) => {
   if (!id) return null;
   const row = await prisma[table].findFirst({
-    where: { id: BigInt(id), deleted_at: null },
+    where: {
+      id: BigInt(id),
+      ...(SOFT_DELETE_TABLES.has(table) ? { deleted_at: null } : {}),
+    },
   });
   if (!row) throw new ApiError(422, `Invalid ${label}`);
   if (requireActive && row.is_active === false) throw new ApiError(422, `${label} is inactive`);
   return row;
 };
 
+const assertGstRate = async (gstRateId) => {
+  if (!gstRateId) return null;
+  const row = await prisma.gst_rates.findFirst({
+    where: { id: BigInt(gstRateId) },
+  });
+  if (!row) throw new ApiError(422, 'Invalid gst_rate_id');
+  if (row.is_active === false) throw new ApiError(422, 'gst_rate_id is inactive');
+  return row;
+};
+
 const assertHsnCode = async (hsnCodeId) => {
   if (!hsnCodeId) return null;
   const row = await prisma.hsn_codes.findFirst({
@@ -102,9 +122,7 @@ const validateItemPayload = async (payload, { isCreate = false } = {}) => {
   }
   if (payload.uom_id) await assertReference('uom', payload.uom_id, 'uom_id');
   if (payload.hsn_code_id !== undefined) await assertHsnCode(payload.hsn_code_id);
-  if (payload.gst_rate_id) {
-    await assertReference('gst_rates', payload.gst_rate_id, 'gst_rate_id', { requireActive: false });
-  }
+  if (payload.gst_rate_id !== undefined) await assertGstRate(payload.gst_rate_id);
   if (payload.brand_id) {
     await assertReference('brands', payload.brand_id, 'brand_id', { requireActive: false });
   }
diff --git a/src/utils/mapDbError.js b/src/utils/mapDbError.js
index 5cd5b5c..fe7c1b1 100644
--- a/src/utils/mapDbError.js
+++ b/src/utils/mapDbError.js
@@ -90,6 +90,10 @@ const mapDbError = (err) => {
   if (err instanceof ApiError) return err;
   if (!err) return null;
 
+  if (err.name === 'PrismaClientValidationError') {
+    return new ApiError(500, 'Internal server error');
+  }
+
   if (err.name === 'PrismaClientKnownRequestError' || err.code?.startsWith?.('P')) {
     const mapped = mapPrismaKnownError(err);
     if (mapped) return mapped;