diff --git a/shierfeng-fastapi-backend/module_business/entity/do/operation_do.py b/shierfeng-fastapi-backend/module_business/entity/do/operation_do.py
index 90147e5..af3edac 100644
--- a/shierfeng-fastapi-backend/module_business/entity/do/operation_do.py
+++ b/shierfeng-fastapi-backend/module_business/entity/do/operation_do.py
@@ -387,7 +387,7 @@ class BizPalletEvent(Base):
 
     event_id = Column(BigInteger, primary_key=True, nullable=False, autoincrement=True, comment='事件ID')
     pallet_id = Column(BigInteger, ForeignKey('biz_pallet.pallet_id'), nullable=False, comment='托盘ID')
-    event_seq = Column(BigInteger, nullable=False, comment='托盘内事件序号')
+    event_seq = Column(Integer, nullable=False, comment='托盘内事件序号')
     event_type = Column(String(32), nullable=False, comment='事件类型')
     source_type = Column(String(32), nullable=False, comment='来源类型')
     source_id = Column(BigInteger, nullable=False, comment='来源记录ID')
diff --git a/shierfeng-fastapi-backend/tests/module_business/test_model_contract.py b/shierfeng-fastapi-backend/tests/module_business/test_model_contract.py
index db8ca37..0e45488 100644
--- a/shierfeng-fastapi-backend/tests/module_business/test_model_contract.py
+++ b/shierfeng-fastapi-backend/tests/module_business/test_model_contract.py
@@ -1,6 +1,6 @@
 import unittest
 
-from sqlalchemy import CHAR, BigInteger, CheckConstraint, Integer, String, Table, UniqueConstraint
+from sqlalchemy import CHAR, BigInteger, CheckConstraint, DateTime, Integer, String, Table, UniqueConstraint
 
 from config.database import Base
 from module_business.entity.do import master_do, operation_do
@@ -228,6 +228,472 @@ EXPECTED_COLUMNS = {
     },
 }
 
+EXPECTED_COLUMN_TYPES = {
+    'biz_strain': {
+        'strain_id': (BigInteger, None),
+        'strain_code': (String, 64),
+        'strain_name': (String, 100),
+        'status': (CHAR, 1),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_warehouse': {
+        'warehouse_id': (BigInteger, None),
+        'warehouse_code': (String, 64),
+        'warehouse_name': (String, 100),
+        'address': (String, 500),
+        'status': (CHAR, 1),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_customer': {
+        'customer_id': (BigInteger, None),
+        'customer_code': (String, 64),
+        'customer_name': (String, 100),
+        'status': (CHAR, 1),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_customer_site': {
+        'site_id': (BigInteger, None),
+        'customer_id': (BigInteger, None),
+        'site_code': (String, 64),
+        'site_name': (String, 100),
+        'address': (String, 500),
+        'status': (CHAR, 1),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_production_line': {
+        'line_id': (BigInteger, None),
+        'site_id': (BigInteger, None),
+        'line_code': (String, 64),
+        'line_name': (String, 100),
+        'status': (CHAR, 1),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_pallet': {
+        'pallet_id': (BigInteger, None),
+        'pallet_code': (String, 64),
+        'qr_token': (String, 128),
+        'capacity_packages': (Integer, None),
+        'asset_status': (CHAR, 1),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_user_warehouse': {
+        'user_id': (BigInteger, None),
+        'warehouse_id': (BigInteger, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+    },
+    'biz_user_site': {
+        'user_id': (BigInteger, None),
+        'site_id': (BigInteger, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+    },
+    'biz_inbound_order': {
+        'inbound_id': (BigInteger, None),
+        'inbound_no': (String, 64),
+        'warehouse_id': (BigInteger, None),
+        'status': (String, 32),
+        'confirm_idempotency_key': (String, 64),
+        'confirm_request_hash': (String, 64),
+        'confirmed_by': (BigInteger, None),
+        'confirmed_at': (DateTime, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_inbound_item': {
+        'inbound_item_id': (BigInteger, None),
+        'inbound_id': (BigInteger, None),
+        'pallet_id': (BigInteger, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+    },
+    'biz_filling_record': {
+        'filling_id': (BigInteger, None),
+        'filling_no': (String, 64),
+        'pallet_id': (BigInteger, None),
+        'warehouse_id': (BigInteger, None),
+        'strain_id': (BigInteger, None),
+        'strain_code_snapshot': (String, 64),
+        'strain_name_snapshot': (String, 100),
+        'batch_no': (String, 64),
+        'package_spec': (String, 64),
+        'initial_packages': (Integer, None),
+        'active_slot': (String, 16),
+        'closed_at': (DateTime, None),
+        'idempotency_key': (String, 64),
+        'request_hash': (String, 64),
+        'operator_id': (BigInteger, None),
+        'operated_at': (DateTime, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_shipment_order': {
+        'shipment_id': (BigInteger, None),
+        'shipment_no': (String, 64),
+        'source_warehouse_id': (BigInteger, None),
+        'target_site_id': (BigInteger, None),
+        'status': (String, 32),
+        'confirm_idempotency_key': (String, 64),
+        'confirm_request_hash': (String, 64),
+        'confirmed_by': (BigInteger, None),
+        'confirmed_at': (DateTime, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_shipment_item': {
+        'shipment_item_id': (BigInteger, None),
+        'shipment_id': (BigInteger, None),
+        'pallet_id': (BigInteger, None),
+        'active_filling_id': (BigInteger, None),
+        'package_qty': (Integer, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+    },
+    'biz_usage_record': {
+        'usage_id': (BigInteger, None),
+        'usage_no': (String, 64),
+        'pallet_id': (BigInteger, None),
+        'active_filling_id': (BigInteger, None),
+        'site_id': (BigInteger, None),
+        'line_id': (BigInteger, None),
+        'used_packages': (Integer, None),
+        'remaining_packages_after': (Integer, None),
+        'idempotency_key': (String, 64),
+        'request_hash': (String, 64),
+        'operator_id': (BigInteger, None),
+        'occurred_at': (DateTime, None),
+    },
+    'biz_return_order': {
+        'return_id': (BigInteger, None),
+        'return_no': (String, 64),
+        'source_site_id': (BigInteger, None),
+        'target_warehouse_id': (BigInteger, None),
+        'status': (String, 32),
+        'request_idempotency_key': (String, 64),
+        'request_hash': (String, 64),
+        'confirm_idempotency_key': (String, 64),
+        'confirm_request_hash': (String, 64),
+        'requested_by': (BigInteger, None),
+        'requested_at': (DateTime, None),
+        'confirmed_by': (BigInteger, None),
+        'confirmed_at': (DateTime, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+        'update_by': (String, 64),
+        'update_time': (DateTime, None),
+        'remark': (String, 500),
+    },
+    'biz_return_item': {
+        'return_item_id': (BigInteger, None),
+        'return_id': (BigInteger, None),
+        'pallet_id': (BigInteger, None),
+        'active_filling_id_snapshot': (BigInteger, None),
+        'remaining_packages_snapshot': (Integer, None),
+        'create_by': (String, 64),
+        'create_time': (DateTime, None),
+    },
+    'biz_pallet_inventory': {
+        'pallet_id': (BigInteger, None),
+        'active_filling_id': (BigInteger, None),
+        'warehouse_id': (BigInteger, None),
+        'site_id': (BigInteger, None),
+        'current_line_id': (BigInteger, None),
+        'flow_state': (String, 32),
+        'remaining_packages': (Integer, None),
+        'last_event_id': (BigInteger, None),
+        'version': (Integer, None),
+        'updated_at': (DateTime, None),
+    },
+    'biz_pallet_event': {
+        'event_id': (BigInteger, None),
+        'pallet_id': (BigInteger, None),
+        'event_seq': (Integer, None),
+        'event_type': (String, 32),
+        'source_type': (String, 32),
+        'source_id': (BigInteger, None),
+        'before_state': (String, 32),
+        'after_state': (String, 32),
+        'before_warehouse_id': (BigInteger, None),
+        'before_site_id': (BigInteger, None),
+        'before_line_id': (BigInteger, None),
+        'after_warehouse_id': (BigInteger, None),
+        'after_site_id': (BigInteger, None),
+        'after_line_id': (BigInteger, None),
+        'before_remaining_packages': (Integer, None),
+        'after_remaining_packages': (Integer, None),
+        'operator_id': (BigInteger, None),
+        'occurred_at': (DateTime, None),
+        'idempotency_key': (String, 64),
+        'request_hash': (String, 64),
+    },
+}
+
+EXPECTED_NULLABILITY = {
+    'biz_strain': {
+        'strain_id': False,
+        'strain_code': False,
+        'strain_name': False,
+        'status': False,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_warehouse': {
+        'warehouse_id': False,
+        'warehouse_code': False,
+        'warehouse_name': False,
+        'address': True,
+        'status': False,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_customer': {
+        'customer_id': False,
+        'customer_code': False,
+        'customer_name': False,
+        'status': False,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_customer_site': {
+        'site_id': False,
+        'customer_id': False,
+        'site_code': False,
+        'site_name': False,
+        'address': True,
+        'status': False,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_production_line': {
+        'line_id': False,
+        'site_id': False,
+        'line_code': False,
+        'line_name': False,
+        'status': False,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_pallet': {
+        'pallet_id': False,
+        'pallet_code': False,
+        'qr_token': False,
+        'capacity_packages': False,
+        'asset_status': False,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_user_warehouse': {
+        'user_id': False,
+        'warehouse_id': False,
+        'create_by': True,
+        'create_time': True,
+    },
+    'biz_user_site': {
+        'user_id': False,
+        'site_id': False,
+        'create_by': True,
+        'create_time': True,
+    },
+    'biz_inbound_order': {
+        'inbound_id': False,
+        'inbound_no': False,
+        'warehouse_id': False,
+        'status': False,
+        'confirm_idempotency_key': True,
+        'confirm_request_hash': True,
+        'confirmed_by': True,
+        'confirmed_at': True,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_inbound_item': {
+        'inbound_item_id': False,
+        'inbound_id': False,
+        'pallet_id': False,
+        'create_by': True,
+        'create_time': True,
+    },
+    'biz_filling_record': {
+        'filling_id': False,
+        'filling_no': False,
+        'pallet_id': False,
+        'warehouse_id': False,
+        'strain_id': False,
+        'strain_code_snapshot': False,
+        'strain_name_snapshot': False,
+        'batch_no': False,
+        'package_spec': False,
+        'initial_packages': False,
+        'active_slot': True,
+        'closed_at': True,
+        'idempotency_key': False,
+        'request_hash': False,
+        'operator_id': False,
+        'operated_at': False,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_shipment_order': {
+        'shipment_id': False,
+        'shipment_no': False,
+        'source_warehouse_id': False,
+        'target_site_id': False,
+        'status': False,
+        'confirm_idempotency_key': True,
+        'confirm_request_hash': True,
+        'confirmed_by': True,
+        'confirmed_at': True,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_shipment_item': {
+        'shipment_item_id': False,
+        'shipment_id': False,
+        'pallet_id': False,
+        'active_filling_id': True,
+        'package_qty': True,
+        'create_by': True,
+        'create_time': True,
+    },
+    'biz_usage_record': {
+        'usage_id': False,
+        'usage_no': False,
+        'pallet_id': False,
+        'active_filling_id': False,
+        'site_id': False,
+        'line_id': False,
+        'used_packages': False,
+        'remaining_packages_after': False,
+        'idempotency_key': False,
+        'request_hash': False,
+        'operator_id': False,
+        'occurred_at': False,
+    },
+    'biz_return_order': {
+        'return_id': False,
+        'return_no': False,
+        'source_site_id': False,
+        'target_warehouse_id': False,
+        'status': False,
+        'request_idempotency_key': False,
+        'request_hash': False,
+        'confirm_idempotency_key': True,
+        'confirm_request_hash': True,
+        'requested_by': False,
+        'requested_at': False,
+        'confirmed_by': True,
+        'confirmed_at': True,
+        'create_by': True,
+        'create_time': True,
+        'update_by': True,
+        'update_time': True,
+        'remark': True,
+    },
+    'biz_return_item': {
+        'return_item_id': False,
+        'return_id': False,
+        'pallet_id': False,
+        'active_filling_id_snapshot': True,
+        'remaining_packages_snapshot': False,
+        'create_by': True,
+        'create_time': True,
+    },
+    'biz_pallet_inventory': {
+        'pallet_id': False,
+        'active_filling_id': True,
+        'warehouse_id': True,
+        'site_id': True,
+        'current_line_id': True,
+        'flow_state': False,
+        'remaining_packages': False,
+        'last_event_id': True,
+        'version': False,
+        'updated_at': False,
+    },
+    'biz_pallet_event': {
+        'event_id': False,
+        'pallet_id': False,
+        'event_seq': False,
+        'event_type': False,
+        'source_type': False,
+        'source_id': False,
+        'before_state': False,
+        'after_state': False,
+        'before_warehouse_id': True,
+        'before_site_id': True,
+        'before_line_id': True,
+        'after_warehouse_id': True,
+        'after_site_id': True,
+        'after_line_id': True,
+        'before_remaining_packages': False,
+        'after_remaining_packages': False,
+        'operator_id': False,
+        'occurred_at': False,
+        'idempotency_key': False,
+        'request_hash': False,
+    },
+}
+
 EXPECTED_PRIMARY_KEYS = {
     'biz_strain': ('strain_id',),
     'biz_warehouse': ('warehouse_id',),
@@ -436,6 +902,34 @@ class BusinessModelContractTest(unittest.TestCase):
                 self.assertEqual(table_name, model.__tablename__)
                 self.assertEqual(EXPECTED_COLUMNS[table_name], set(model.__table__.columns.keys()))
 
+    def test_every_column_type_and_string_length_matches_contract(self) -> None:
+        business_tables = {name for name in Base.metadata.tables if name.startswith('biz_')}
+        self.assertEqual(business_tables, set(EXPECTED_COLUMN_TYPES))
+
+        for table_name, expected_columns in EXPECTED_COLUMN_TYPES.items():
+            table = Base.metadata.tables[table_name]
+            with self.subTest(table_name=table_name, contract='all_type_columns'):
+                self.assertEqual(set(expected_columns), set(table.columns.keys()))
+
+            for column_name, (expected_type, expected_length) in expected_columns.items():
+                column_type = table.c[column_name].type
+                with self.subTest(table_name=table_name, column_name=column_name):
+                    self.assertIs(expected_type, type(column_type))
+                    self.assertEqual(expected_length, getattr(column_type, 'length', None))
+
+    def test_every_column_nullable_flag_matches_contract(self) -> None:
+        business_tables = {name for name in Base.metadata.tables if name.startswith('biz_')}
+        self.assertEqual(business_tables, set(EXPECTED_NULLABILITY))
+
+        for table_name, expected_columns in EXPECTED_NULLABILITY.items():
+            table = Base.metadata.tables[table_name]
+            with self.subTest(table_name=table_name, contract='all_nullable_columns'):
+                self.assertEqual(set(expected_columns), set(table.columns.keys()))
+
+            for column_name, expected_nullable in expected_columns.items():
+                with self.subTest(table_name=table_name, column_name=column_name):
+                    self.assertIs(expected_nullable, table.c[column_name].nullable)
+
     def test_primary_keys_and_foreign_keys_match_contract(self) -> None:
         for table_name, expected_primary_key in EXPECTED_PRIMARY_KEYS.items():
             table = Base.metadata.tables[table_name]