diff --git a/CHANGELOG.md b/CHANGELOG.md
index 39309fe..2c26baa 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,41 @@ All notable changes to pyCOREPOS will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## v0.5.1 (2025-02-20)
+
+### Fix
+
+- add `Product.default_vendor_item` convenience property
+
+## v0.5.0 (2025-02-01)
+
+### Feat
+
+- use true column names for transaction data models
+
+### Fix
+
+- define common base schema for Product model
+- add `Parameter` model for lane_op
+- add model for lane_trans `LocalTrans`
+
+## v0.4.0 (2025-01-24)
+
+### Feat
+
+- add common base class for `dtransactions` and similar models
+
+### Fix
+
+- add `Employee` model for lane_op
+- fix ordering of name columns for MemberInfo
+
+## v0.3.5 (2025-01-15)
+
+### Fix
+
+- add workaround to avoid missing schema columns
+
 ## v0.3.4 (2025-01-15)
 
 ### Fix
diff --git a/corepos/db/common/__init__.py b/corepos/db/common/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/corepos/db/common/op.py b/corepos/db/common/op.py
new file mode 100644
index 0000000..30ecc1c
--- /dev/null
+++ b/corepos/db/common/op.py
@@ -0,0 +1,173 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  pyCOREPOS -- Python Interface to CORE POS
+#  Copyright © 2018-2025 Lance Edgar
+#
+#  This file is part of pyCOREPOS.
+#
+#  pyCOREPOS is free software: you can redistribute it and/or modify it under
+#  the terms of the GNU General Public License as published by the Free
+#  Software Foundation, either version 3 of the License, or (at your option)
+#  any later version.
+#
+#  pyCOREPOS is distributed in the hope that it will be useful, but WITHOUT ANY
+#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+#  details.
+#
+#  You should have received a copy of the GNU General Public License along with
+#  pyCOREPOS.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+"""
+Common schema for operational data models
+"""
+
+import sqlalchemy as sa
+
+
+class ParameterBase:
+    """
+    Base class for Parameter models, shared by Office + Lane.
+    """
+    store_id = sa.Column(sa.SmallInteger(), primary_key=True, nullable=False)
+
+    lane_id = sa.Column(sa.SmallInteger(), primary_key=True, nullable=False)
+
+    param_key = sa.Column(sa.String(length=100), primary_key=True, nullable=False)
+
+    param_value = sa.Column(sa.String(length=255), nullable=True)
+
+    is_array = sa.Column(sa.Boolean(), nullable=True)
+
+    def __str__(self):
+        return f"{self.store_id}-{self.lane_id} {self.param_key}"
+
+
+class EmployeeBase:
+    """
+    Base class for Employee models, shared by Office + Lane.
+    """
+    number = sa.Column('emp_no', sa.SmallInteger(), nullable=False,
+                       primary_key=True, autoincrement=False)
+
+    cashier_password = sa.Column('CashierPassword', sa.String(length=50), nullable=True)
+
+    admin_password = sa.Column('AdminPassword', sa.String(length=50), nullable=True)
+
+    first_name = sa.Column('FirstName', sa.String(length=255), nullable=True)
+
+    last_name = sa.Column('LastName', sa.String(length=255), nullable=True)
+
+    job_title = sa.Column('JobTitle', sa.String(length=255), nullable=True)
+
+    active = sa.Column('EmpActive', sa.Boolean(), nullable=True)
+
+    frontend_security = sa.Column('frontendsecurity', sa.SmallInteger(), nullable=True)
+
+    backend_security = sa.Column('backendsecurity', sa.SmallInteger(), nullable=True)
+
+    birth_date = sa.Column('birthdate', sa.DateTime(), nullable=True)
+
+    def __str__(self):
+        return ' '.join([self.first_name or '', self.last_name or '']).strip()
+
+
+class ProductBase:
+    """
+    Base class for Product models, shared by Office + Lane.
+    """
+    id = sa.Column(sa.Integer(), nullable=False, primary_key=True, autoincrement=True)
+
+    upc = sa.Column(sa.String(length=13), nullable=True)
+
+    description = sa.Column(sa.String(length=30), nullable=True)
+
+    brand = sa.Column(sa.String(length=30), nullable=True)
+
+    formatted_name = sa.Column(sa.String(length=30), nullable=True)
+
+    normal_price = sa.Column(sa.Float(), nullable=True)
+
+    price_method = sa.Column('pricemethod', sa.SmallInteger(), nullable=True)
+
+    group_price = sa.Column('groupprice', sa.Float(), nullable=True)
+
+    quantity = sa.Column(sa.SmallInteger(), nullable=True)
+
+    special_price = sa.Column(sa.Float(), nullable=True)
+
+    special_price_method = sa.Column('specialpricemethod', sa.SmallInteger(), nullable=True)
+
+    special_group_price = sa.Column('specialgroupprice', sa.Float(), nullable=True)
+
+    special_quantity = sa.Column('specialquantity', sa.SmallInteger(), nullable=True)
+
+    special_limit = sa.Column(sa.SmallInteger(), nullable=True)
+
+    start_date = sa.Column(sa.DateTime(), nullable=True)
+
+    end_date = sa.Column(sa.DateTime(), nullable=True)
+
+    department_number = sa.Column('department', sa.SmallInteger(), nullable=True)
+
+    size = sa.Column(sa.String(length=9), nullable=True)
+
+    tax_rate_id = sa.Column('tax', sa.SmallInteger(), nullable=True)
+
+    foodstamp = sa.Column(sa.Boolean(), nullable=True)
+
+    scale = sa.Column(sa.Boolean(), nullable=True)
+
+    scale_price = sa.Column('scaleprice', sa.Float(), nullable=True)
+
+    mix_match_code = sa.Column('mixmatchcode', sa.String(length=13), nullable=True)
+
+    created = sa.Column(sa.DateTime(), nullable=True)
+
+    modified = sa.Column(sa.DateTime(), nullable=True)
+
+    tare_weight = sa.Column('tareweight', sa.Float(), nullable=True)
+
+    discount = sa.Column(sa.SmallInteger(), nullable=True)
+
+    discount_type = sa.Column('discounttype', sa.SmallInteger(), nullable=True)
+
+    line_item_discountable = sa.Column(sa.Boolean(), nullable=True)
+
+    unit_of_measure = sa.Column('unitofmeasure', sa.String(length=15), nullable=True)
+
+    wicable = sa.Column(sa.SmallInteger(), nullable=True)
+
+    quantity_enforced = sa.Column('qttyEnforced', sa.Boolean(), nullable=True)
+
+    id_enforced = sa.Column('idEnforced', sa.SmallInteger(), nullable=True)
+
+    cost = sa.Column(sa.Float(), nullable=True)
+
+    special_cost = sa.Column(sa.Float(), nullable=True)
+
+    received_cost = sa.Column(sa.Float(), nullable=True)
+
+    in_use = sa.Column('inUse', sa.Boolean(), nullable=True)
+
+    numflag = sa.Column(sa.Integer(), nullable=True)
+
+    subdepartment_number = sa.Column('subdept', sa.SmallInteger(), nullable=True)
+
+    deposit = sa.Column(sa.Float(), nullable=True)
+
+    local = sa.Column(sa.Integer(), nullable=True, default=0)
+
+    store_id = sa.Column(sa.SmallInteger(), nullable=True)
+
+    default_vendor_id = sa.Column(sa.Integer(), nullable=True)
+
+    current_origin_id = sa.Column(sa.Integer(), nullable=True)
+
+    auto_par = sa.Column(sa.Float(), nullable=True, default=0)
+
+    price_rule_id = sa.Column(sa.Integer(), nullable=True, default=0)
+
+    last_sold = sa.Column(sa.DateTime(), nullable=True)
diff --git a/corepos/db/common/trans.py b/corepos/db/common/trans.py
new file mode 100644
index 0000000..9ec5601
--- /dev/null
+++ b/corepos/db/common/trans.py
@@ -0,0 +1,114 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  pyCOREPOS -- Python Interface to CORE POS
+#  Copyright © 2018-2025 Lance Edgar
+#
+#  This file is part of pyCOREPOS.
+#
+#  pyCOREPOS is free software: you can redistribute it and/or modify it under
+#  the terms of the GNU General Public License as published by the Free
+#  Software Foundation, either version 3 of the License, or (at your option)
+#  any later version.
+#
+#  pyCOREPOS is distributed in the hope that it will be useful, but WITHOUT ANY
+#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+#  details.
+#
+#  You should have received a copy of the GNU General Public License along with
+#  pyCOREPOS.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+"""
+Common schema for transaction data models
+"""
+
+import sqlalchemy as sa
+from sqlalchemy import orm
+from sqlalchemy.ext.declarative import declared_attr
+
+
+class TransactionDetailBase:
+    """
+    Base class for POS transaction detail models, shared by Office +
+    Lane.
+    """
+
+    # register
+    register_no = sa.Column(sa.Integer(), nullable=True)
+
+    # txn
+    trans_id = sa.Column(sa.Integer(), nullable=True)
+    trans_no = sa.Column(sa.Integer(), nullable=True)
+    trans_type = sa.Column(sa.String(length=1), nullable=True)
+    trans_subtype = sa.Column(sa.String(length=2), nullable=True)
+    trans_status = sa.Column(sa.String(length=1), nullable=True)
+
+    # cashier
+    emp_no = sa.Column(sa.Integer(), nullable=True)
+
+    # customer
+    card_no = sa.Column(sa.Integer(), nullable=True)
+    memType = sa.Column(sa.Integer(), nullable=True)
+    staff = sa.Column(sa.Boolean(), nullable=True)
+
+    ##############################
+    # remainder is "line item" ...
+    ##############################
+
+    upc = sa.Column(sa.String(length=13), nullable=True)
+
+    department = sa.Column(sa.Integer(), nullable=True)
+
+    description = sa.Column(sa.String(length=30), nullable=True)
+
+    quantity = sa.Column(sa.Float(), nullable=True)
+
+    scale = sa.Column(sa.Boolean(), nullable=True, default=False)
+
+    cost = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
+
+    unitPrice = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
+
+    total = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
+
+    regPrice = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
+
+    tax = sa.Column(sa.SmallInteger(), nullable=True)
+
+    foodstamp = sa.Column(sa.Boolean(), nullable=True)
+
+    discount = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
+
+    memDiscount = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
+
+    discountable = sa.Column(sa.Boolean(), nullable=True)
+
+    discounttype = sa.Column(sa.Integer(), nullable=True)
+
+    voided = sa.Column(sa.Integer(), nullable=True)
+
+    percentDiscount = sa.Column(sa.Integer(), nullable=True)
+
+    ItemQtty = sa.Column(sa.Float(), nullable=True)
+
+    volDiscType = sa.Column(sa.Integer(), nullable=True)
+
+    volume = sa.Column(sa.Integer(), nullable=True)
+
+    VolSpecial = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
+
+    mixMatch = sa.Column(sa.String(length=13), nullable=True)
+
+    matched = sa.Column(sa.Boolean(), nullable=True)
+
+    numflag = sa.Column(sa.Integer(), nullable=True, default=0)
+
+    charflag = sa.Column(sa.String(length=2), nullable=True)
+
+    def __str__(self):
+        txnid = '-'.join([str(val) for val in [self.register_no,
+                                               self.trans_no,
+                                               self.trans_id]])
+        return f"{txnid} {self.description or ''}"
diff --git a/corepos/db/lane_op/model.py b/corepos/db/lane_op/model.py
index c7ed5b2..456b1b8 100644
--- a/corepos/db/lane_op/model.py
+++ b/corepos/db/lane_op/model.py
@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  pyCOREPOS -- Python Interface to CORE POS
-#  Copyright © 2018-2023 Lance Edgar
+#  Copyright © 2018-2025 Lance Edgar
 #
 #  This file is part of pyCOREPOS.
 #
@@ -27,10 +27,26 @@ Data model for CORE POS "lane_op" DB
 import sqlalchemy as sa
 from sqlalchemy import orm
 
+from corepos.db.common import op as common
+
 
 Base = orm.declarative_base()
 
 
+class Parameter(common.ParameterBase, Base):
+    """
+    Data model for ``parameters`` table.
+    """
+    __tablename__ = 'parameters'
+
+
+class Employee(common.EmployeeBase, Base):
+    """
+    Data model for ``employees`` table.
+    """
+    __tablename__ = 'employees'
+
+
 class Department(Base):
     """
     Represents a department within the organization.
@@ -72,141 +88,11 @@ class Department(Base):
         return self.name or ""
 
 
-class Product(Base):
+class Product(common.ProductBase, Base):
     """
-    Represents a product, purchased and/or sold by the organization.
+    Data model for ``products`` table.
     """
     __tablename__ = 'products'
-    # __table_args__ = (
-    #     sa.ForeignKeyConstraint(['department'], ['departments.dept_no']),
-    #     sa.ForeignKeyConstraint(['subdept'], ['subdepts.subdept_no']),
-    #     sa.ForeignKeyConstraint(['tax'], ['taxrates.id']),
-    # )
-
-    id = sa.Column(sa.Integer(), nullable=False, 
-                   primary_key=True, autoincrement=True)
-
-    upc = sa.Column(sa.String(length=13), nullable=True)
-
-    description = sa.Column(sa.String(length=30), nullable=True)
-
-    brand = sa.Column(sa.String(length=30), nullable=True)
-
-    formatted_name = sa.Column(sa.String(length=30), nullable=True)
-
-    normal_price = sa.Column(sa.Float(), nullable=True)
-
-    price_method = sa.Column('pricemethod', sa.SmallInteger(), nullable=True)
-
-    group_price = sa.Column('groupprice', sa.Float(), nullable=True)
-
-    quantity = sa.Column(sa.SmallInteger(), nullable=True)
-
-    special_price = sa.Column(sa.Float(), nullable=True)
-
-    special_price_method = sa.Column('specialpricemethod', sa.SmallInteger(), nullable=True)
-
-    special_group_price = sa.Column('specialgroupprice', sa.Float(), nullable=True)
-
-    special_quantity = sa.Column('specialquantity', sa.SmallInteger(), nullable=True)
-
-    special_limit = sa.Column(sa.SmallInteger(), nullable=True)
-
-    start_date = sa.Column(sa.DateTime(), nullable=True)
-
-    end_date = sa.Column(sa.DateTime(), nullable=True)
-
-    department_number = sa.Column('department', sa.SmallInteger(), nullable=True)
-    # department = orm.relationship(
-    #     Department,
-    #     primaryjoin=Department.number == department_number,
-    #     foreign_keys=[department_number],
-    #     doc="""
-    #     Reference to the :class:`Department` to which the product belongs.
-    #     """)
-
-    size = sa.Column(sa.String(length=9), nullable=True)
-
-    tax_rate_id = sa.Column('tax', sa.SmallInteger(), nullable=True)
-    # tax_rate = orm.relationship(TaxRate)
-
-    foodstamp = sa.Column(sa.Boolean(), nullable=True)
-
-    scale = sa.Column(sa.Boolean(), nullable=True)
-
-    scale_price = sa.Column('scaleprice', sa.Float(), nullable=True)
-
-    mix_match_code = sa.Column('mixmatchcode', sa.String(length=13), nullable=True)
-
-    created = sa.Column(sa.DateTime(), nullable=True)
-
-    modified = sa.Column(sa.DateTime(), nullable=True)
-
-    # TODO: what to do about this 'replaces' thing?
-    # 'batchID'=>array('type'=>'TINYINT', 'replaces'=>'advertised'),
-    # batch_id = sa.Column('batchID', sa.SmallInteger(), nullable=True)
-    # advertised = sa.Column(sa.Boolean(), nullable=True)
-
-    tare_weight = sa.Column('tareweight', sa.Float(), nullable=True)
-
-    discount = sa.Column(sa.SmallInteger(), nullable=True)
-
-    discount_type = sa.Column('discounttype', sa.SmallInteger(), nullable=True)
-
-    line_item_discountable = sa.Column(sa.Boolean(), nullable=True)
-
-    unit_of_measure = sa.Column('unitofmeasure', sa.String(length=15), nullable=True)
-
-    wicable = sa.Column(sa.SmallInteger(), nullable=True)
-
-    quantity_enforced = sa.Column('qttyEnforced', sa.Boolean(), nullable=True)
-
-    id_enforced = sa.Column('idEnforced', sa.SmallInteger(), nullable=True)
-
-    cost = sa.Column(sa.Float(), nullable=True)
-
-    special_cost = sa.Column(sa.Float(), nullable=True)
-
-    received_cost = sa.Column(sa.Float(), nullable=True)
-
-    in_use = sa.Column('inUse', sa.Boolean(), nullable=True)
-
-    flags = sa.Column('numflag', sa.Integer(), nullable=True)
-
-    subdepartment_number = sa.Column('subdept', sa.SmallInteger(), nullable=True)
-    # subdepartment = orm.relationship(
-    #     Subdepartment,
-    #     primaryjoin=Subdepartment.number == subdepartment_number,
-    #     foreign_keys=[subdepartment_number],
-    #     doc="""
-    #     Reference to the :class:`Subdepartment` to which the product belongs.
-    #     """)
-
-    deposit = sa.Column(sa.Float(), nullable=True)
-
-    local = sa.Column(sa.Integer(), nullable=True,
-                      default=0) # TODO: do we want a default here?
-
-    store_id = sa.Column(sa.SmallInteger(), nullable=True)
-
-    default_vendor_id = sa.Column(sa.Integer(), nullable=True)
-    # default_vendor = orm.relationship(
-    #     Vendor,
-    #     primaryjoin=Vendor.id == default_vendor_id,
-    #     foreign_keys=[default_vendor_id],
-    #     doc="""
-    #     Reference to the default :class:`Vendor` from which the product is obtained.
-    #     """)
-
-    current_origin_id = sa.Column(sa.Integer(), nullable=True)
-
-    auto_par = sa.Column(sa.Float(), nullable=True,
-                         default=0) # TODO: do we want a default here?
-
-    price_rule_id = sa.Column(sa.Integer(), nullable=True)
-
-    # TODO: some older DB's might not have this?  guess we'll see
-    last_sold = sa.Column(sa.DateTime(), nullable=True)
 
 
 class CustomerClassic(Base):
diff --git a/corepos/db/lane_trans/__init__.py b/corepos/db/lane_trans/__init__.py
new file mode 100644
index 0000000..8e8c706
--- /dev/null
+++ b/corepos/db/lane_trans/__init__.py
@@ -0,0 +1,30 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  pyCOREPOS -- Python Interface to CORE POS
+#  Copyright © 2018-2025 Lance Edgar
+#
+#  This file is part of pyCOREPOS.
+#
+#  pyCOREPOS is free software: you can redistribute it and/or modify it under
+#  the terms of the GNU General Public License as published by the Free
+#  Software Foundation, either version 3 of the License, or (at your option)
+#  any later version.
+#
+#  pyCOREPOS is distributed in the hope that it will be useful, but WITHOUT ANY
+#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+#  details.
+#
+#  You should have received a copy of the GNU General Public License along with
+#  pyCOREPOS.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+"""
+Lane Transaction Database
+"""
+
+from sqlalchemy import orm
+
+
+Session = orm.sessionmaker()
diff --git a/corepos/db/lane_trans/model.py b/corepos/db/lane_trans/model.py
new file mode 100644
index 0000000..f2245f5
--- /dev/null
+++ b/corepos/db/lane_trans/model.py
@@ -0,0 +1,79 @@
+# -*- coding: utf-8; -*-
+################################################################################
+#
+#  pyCOREPOS -- Python Interface to CORE POS
+#  Copyright © 2018-2025 Lance Edgar
+#
+#  This file is part of pyCOREPOS.
+#
+#  pyCOREPOS is free software: you can redistribute it and/or modify it under
+#  the terms of the GNU General Public License as published by the Free
+#  Software Foundation, either version 3 of the License, or (at your option)
+#  any later version.
+#
+#  pyCOREPOS is distributed in the hope that it will be useful, but WITHOUT ANY
+#  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+#  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+#  details.
+#
+#  You should have received a copy of the GNU General Public License along with
+#  pyCOREPOS.  If not, see <http://www.gnu.org/licenses/>.
+#
+################################################################################
+"""
+Data model for CORE POS "lane_trans" DB
+"""
+
+import sqlalchemy as sa
+from sqlalchemy import orm
+from sqlalchemy.ext.declarative import declared_attr
+
+from corepos.db.common import trans as common
+
+
+Base = orm.declarative_base()
+
+
+class DTransactionBase(common.TransactionDetailBase):
+    """
+    Base class for ``dtransactions`` and similar models.
+    """
+    pos_row_id = sa.Column(sa.Integer(), primary_key=True, nullable=False)
+
+    store_id = sa.Column(sa.Integer(), nullable=True, default=0)
+    date_time = sa.Column('datetime', sa.DateTime(), nullable=True)
+
+
+class DTransaction(DTransactionBase, Base):
+    """
+    Data model for ``dtransactions`` table.
+    """
+    __tablename__ = 'dtransactions'
+
+
+class LocalTransBase(common.TransactionDetailBase):
+    """
+    Base class for ``localtrans`` and similar models.
+    """
+
+    @declared_attr
+    def __table_args__(self):
+        return (
+            sa.PrimaryKeyConstraint('trans_id'),
+        )
+
+    date_time = sa.Column('datetime', sa.DateTime(), nullable=True)
+
+
+class LocalTrans(LocalTransBase, Base):
+    """
+    Data model for ``localtrans`` table.
+    """
+    __tablename__ = 'localtrans'
+
+
+class LocalTempTrans(LocalTransBase, Base):
+    """
+    Data model for ``localtemptrans`` table.
+    """
+    __tablename__ = 'localtemptrans'
diff --git a/corepos/db/office_arch/model.py b/corepos/db/office_arch/model.py
index 49b0bbd..bc5838f 100644
--- a/corepos/db/office_arch/model.py
+++ b/corepos/db/office_arch/model.py
@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  pyCOREPOS -- Python Interface to CORE POS
-#  Copyright © 2018-2024 Lance Edgar
+#  Copyright © 2018-2025 Lance Edgar
 #
 #  This file is part of pyCOREPOS.
 #
@@ -24,9 +24,11 @@
 CORE Office "arch" data model
 """
 
+import sqlalchemy as sa
 from sqlalchemy import orm
 
-from corepos.db.office_trans.model import DTransactionBase, DLogBase
+from corepos.db.common import trans as common
+from corepos.db.office_trans.model import DTransactionBase
 
 
 Base = orm.declarative_base()
@@ -34,7 +36,7 @@ Base = orm.declarative_base()
 
 class BigArchive(DTransactionBase, Base):
     """
-    Represents a record from ``bigArchive`` table.
+    Data model for ``bigArchive`` table.
     """
     __tablename__ = 'bigArchive'
 
@@ -43,8 +45,19 @@ class BigArchive(DTransactionBase, Base):
 TransactionDetail = BigArchive
 
 
+class DLogBase(common.TransactionDetailBase):
+    """
+    Base class for ``dlogBig`` and similar models.
+    """
+    store_row_id = sa.Column(sa.Integer(), primary_key=True, nullable=False)
+
+    store_id = sa.Column(sa.Integer(), nullable=True, default=0)
+    pos_row_id = sa.Column(sa.Integer(), nullable=True)
+    date_time = sa.Column('tdate', sa.DateTime(), nullable=True)
+
+
 class DLogBig(DLogBase, Base):
     """
-    Represents a record from ``dlogBig`` view.
+    Data model for ``dlogBig`` view.
     """
     __tablename__ = 'dlogBig'
diff --git a/corepos/db/office_op/model.py b/corepos/db/office_op/model.py
index 6087f67..60ad478 100644
--- a/corepos/db/office_op/model.py
+++ b/corepos/db/office_op/model.py
@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  pyCOREPOS -- Python Interface to CORE POS
-#  Copyright © 2018-2024 Lance Edgar
+#  Copyright © 2018-2025 Lance Edgar
 #
 #  This file is part of pyCOREPOS.
 #
@@ -31,6 +31,8 @@ import sqlalchemy as sa
 from sqlalchemy import orm
 from sqlalchemy.ext.associationproxy import association_proxy
 
+from corepos.db.common import op as common
+
 
 log = logging.getLogger(__name__)
 
@@ -54,25 +56,12 @@ class StringableDateTime(sa.TypeDecorator):
         raise NotImplementedError
 
 
-class Parameter(Base):
+class Parameter(common.ParameterBase, Base):
     """
-    Represents a "parameter" value.
+    Data model for ``parameters`` table.
     """
     __tablename__ = 'parameters'
 
-    store_id = sa.Column(sa.SmallInteger(), primary_key=True, nullable=False)
-
-    lane_id = sa.Column(sa.SmallInteger(), primary_key=True, nullable=False)
-
-    param_key = sa.Column(sa.String(length=100), primary_key=True, nullable=False)
-
-    param_value = sa.Column(sa.String(length=255), nullable=True)
-
-    is_array = sa.Column(sa.Boolean(), nullable=True)
-
-    def __str__(self):
-        return "{}-{} {}".format(self.store_id, self.lane_id, self.param_key)
-
 
 class TableSyncRule(Base):
     """
@@ -547,7 +536,7 @@ class Origin(Base):
         return self.name or self.short_name or ""
 
 
-class Product(Base):
+class Product(common.ProductBase, Base):
     """
     Represents a product, purchased and/or sold by the organization.
     """
@@ -558,125 +547,68 @@ class Product(Base):
         sa.ForeignKeyConstraint(['tax'], ['taxrates.id']),
     )
 
-    id = sa.Column(sa.Integer(), primary_key=True, autoincrement=True, nullable=False)
-
-    upc = sa.Column(sa.String(length=13), nullable=True)
-
-    description = sa.Column(sa.String(length=30), nullable=True)
-
-    brand = sa.Column(sa.String(length=30), nullable=True)
-
-    formatted_name = sa.Column(sa.String(length=30), nullable=True)
-
-    normal_price = sa.Column(sa.Float(), nullable=True)
-
-    price_method = sa.Column('pricemethod', sa.SmallInteger(), nullable=True)
-
-    group_price = sa.Column('groupprice', sa.Float(), nullable=True)
-
-    quantity = sa.Column(sa.SmallInteger(), nullable=True)
-
-    special_price = sa.Column(sa.Float(), nullable=True)
-
-    special_price_method = sa.Column('specialpricemethod', sa.SmallInteger(), nullable=True)
-
-    special_group_price = sa.Column('specialgroupprice', sa.Float(), nullable=True)
-
-    special_quantity = sa.Column('specialquantity', sa.SmallInteger(), nullable=True)
-
-    start_date = sa.Column(sa.DateTime(), nullable=True)
-
-    end_date = sa.Column(sa.DateTime(), nullable=True)
-
-    department_number = sa.Column('department', sa.SmallInteger(), nullable=True)
     department = orm.relationship(
         Department,
-        primaryjoin=Department.number == department_number,
-        foreign_keys=[department_number],
+        primaryjoin='Department.number == Product.department_number',
+        foreign_keys='Product.department_number',
         doc="""
         Reference to the :class:`Department` to which the product belongs.
         """)
 
-    size = sa.Column(sa.String(length=9), nullable=True)
-
-    tax_rate_id = sa.Column('tax', sa.SmallInteger(), nullable=True)
     tax_rate = orm.relationship(TaxRate)
 
-    foodstamp = sa.Column(sa.Boolean(), nullable=True)
-
-    scale = sa.Column(sa.Boolean(), nullable=True)
-
-    # TODO: yikes, did i just code this all wrong the first time?  pretty sure
-    # this needs to change to a decimal column...
-    scale_price = sa.Column('scaleprice', sa.Boolean(), nullable=True)
-    # scale_price = sa.Column('scaleprice', sa.Numeric(precision=10, scale=2), nullable=True)
-
-    mix_match_code = sa.Column('mixmatchcode', sa.String(length=13), nullable=True)
-
-    created = sa.Column(StringableDateTime(), nullable=True)
-
-    modified = sa.Column(sa.DateTime(), nullable=True)
-
     # advertised = sa.Column(sa.Boolean(), nullable=True)
 
-    tare_weight = sa.Column('tareweight', sa.Float(), nullable=True)
-
-    discount = sa.Column(sa.SmallInteger(), nullable=True)
-
-    discount_type = sa.Column('discounttype', sa.SmallInteger(), nullable=True)
-
-    line_item_discountable = sa.Column(sa.Boolean(), nullable=True)
-
-    unit_of_measure = sa.Column('unitofmeasure', sa.String(length=15), nullable=True)
-
-    wicable = sa.Column(sa.SmallInteger(), nullable=True)
-
-    quantity_enforced = sa.Column('qttyEnforced', sa.Boolean(), nullable=True)
-
-    id_enforced = sa.Column('idEnforced', sa.SmallInteger(), nullable=True)
-
-    cost = sa.Column(sa.Float(), nullable=True)
-
-    in_use = sa.Column('inUse', sa.Boolean(), nullable=True)
-
-    flags = sa.Column('numflag', sa.Integer(), nullable=True)
-
-    subdepartment_number = sa.Column('subdept', sa.SmallInteger(), nullable=True)
     subdepartment = orm.relationship(
         Subdepartment,
-        primaryjoin=Subdepartment.number == subdepartment_number,
-        foreign_keys=[subdepartment_number],
+        primaryjoin='Subdepartment.number == Product.subdepartment_number',
+        foreign_keys='Product.subdepartment_number',
         doc="""
         Reference to the :class:`Subdepartment` to which the product belongs.
         """)
 
-    deposit = sa.Column(sa.Float(), nullable=True)
-
-    local = sa.Column(sa.Integer(), nullable=True)
-
-    store_id = sa.Column(sa.SmallInteger(), nullable=True)
-
-    default_vendor_id = sa.Column(sa.Integer(), nullable=True)
     default_vendor = orm.relationship(
         Vendor,
-        primaryjoin=Vendor.id == default_vendor_id,
-        foreign_keys=[default_vendor_id],
+        primaryjoin='Vendor.id == Product.default_vendor_id',
+        foreign_keys='Product.default_vendor_id',
         doc="""
         Reference to the default :class:`Vendor` from which the product is obtained.
         """)
+
     # TODO: deprecate / remove this?
     vendor = orm.synonym('default_vendor')
 
-    current_origin_id = sa.Column(sa.Integer(), nullable=True)
-
-    # TODO: some older DB's might not have this?  guess we'll see
-    last_sold = sa.Column(sa.DateTime(), nullable=True)
-
     like_code = association_proxy(
         '_like_code', 'like_code',
         creator=lambda lc: ProductLikeCode(like_code=lc),
     )
 
+    vendor_items = orm.relationship(
+        'VendorItem',
+        back_populates='product',
+        primaryjoin='VendorItem.upc == Product.upc',
+        foreign_keys='VendorItem.upc',
+        order_by='VendorItem.vendor_item_id',
+        doc="""
+        List of :class:`VendorItem` records for this product.
+        """)
+
+    @property
+    def default_vendor_item(self):
+        """
+        Returns the "default" vendor item record.  This will
+        correspond to the :attr:`default_vendor` if possible.
+
+        :rtype: :class:`VendorItem` or ``None``
+        """
+        if self.default_vendor:
+            for item in self.vendor_items:
+                if item.vendor_id == self.default_vendor.id:
+                    return item
+
+        if self.vendor_items:
+            return self.vendor_items[0]
+
     @property
     def full_description(self):
         fields = ['brand', 'description', 'size']
@@ -826,17 +758,12 @@ class VendorItem(Base):
     upc = sa.Column(sa.String(length=13), nullable=False)
     product = orm.relationship(
         Product,
+        back_populates='vendor_items',
         primaryjoin=Product.upc == upc,
         foreign_keys=[upc],
         doc="""
         Reference to the :class:`Product` to which this record applies.
-        """,
-        backref=orm.backref(
-            'vendor_items',
-            order_by=vendor_item_id,
-            doc="""
-            List of :class:`VendorItem` records for this product.
-            """))
+        """)
 
     brand = sa.Column(sa.String(length=50), nullable=True)
 
@@ -991,35 +918,12 @@ class ProductPhysicalLocation(Base):
     location = sa.Column(sa.SmallInteger(), nullable=True, default=0)
 
 
-class Employee(Base):
+class Employee(common.EmployeeBase, Base):
     """
-    Represents an employee within the organization.
+    Data model for ``employees`` table.
     """
     __tablename__ = 'employees'
 
-    number = sa.Column('emp_no', sa.SmallInteger(), primary_key=True, autoincrement=False, nullable=False)
-
-    cashier_password = sa.Column('CashierPassword', sa.String(length=50), nullable=True)
-
-    admin_password = sa.Column('AdminPassword', sa.String(length=50), nullable=True)
-
-    first_name = sa.Column('FirstName', sa.String(length=255), nullable=True)
-
-    last_name = sa.Column('LastName', sa.String(length=255), nullable=True)
-
-    job_title = sa.Column('JobTitle', sa.String(length=255), nullable=True)
-
-    active = sa.Column('EmpActive', sa.Boolean(), nullable=True)
-
-    frontend_security = sa.Column('frontendsecurity', sa.SmallInteger(), nullable=True)
-
-    backend_security = sa.Column('backendsecurity', sa.SmallInteger(), nullable=True)
-
-    birth_date = sa.Column('birthdate', sa.DateTime(), nullable=True)
-
-    def __str__(self):
-        return ' '.join([self.first_name or '', self.last_name or '']).strip()
-
 
 class MemberType(Base):
     """
@@ -1039,12 +943,11 @@ class MemberType(Base):
 
     ssi = sa.Column(sa.Boolean(), nullable=True)
 
-    ignoreSales = sa.Column(sa.Boolean(), nullable=True, default=False)
-    ignore_sales = orm.synonym('ignoreSales')
+    # nb. this must be added explicitly if DB is new enough
+    #ignore_sales = sa.Column('ignoreSales', sa.Boolean(), nullable=True, default=False)
 
-    # TODO: this was apparently added "recently" - isn't present in all DBs
-    # (need to figure out how to conditionally include it in model?)
-    # sales_code = sa.Column('salesCode', sa.Integer(), nullable=True)
+    # nb. this must be added explicitly if DB is new enough
+    #sales_code = sa.Column('salesCode', sa.Integer(), nullable=True)
 
     def __str__(self):
         return self.description or ""
@@ -1260,14 +1163,14 @@ class MemberInfo(Base):
 
     card_number = sa.Column('card_no', sa.Integer(), primary_key=True, autoincrement=False, nullable=False)
 
-    last_name = sa.Column(sa.String(length=30), nullable=True)
-
     first_name = sa.Column(sa.String(length=30), nullable=True)
 
-    other_last_name = sa.Column('othlast_name', sa.String(length=30), nullable=True)
+    last_name = sa.Column(sa.String(length=30), nullable=True)
 
     other_first_name = sa.Column('othfirst_name', sa.String(length=30), nullable=True)
 
+    other_last_name = sa.Column('othlast_name', sa.String(length=30), nullable=True)
+
     street = sa.Column(sa.String(length=255), nullable=True)
 
     city = sa.Column(sa.String(length=20), nullable=True)
@@ -1842,3 +1745,22 @@ class PurchaseOrderNote(Base):
 
     def __str__(self):
         return self.notes or ""
+
+
+# the rest of this is a workaround to deal with the fact that some
+# CORE databases have columns which others do not.  i had assumed that
+# all would be more or less the same but not so in practice.  so if
+# your DB *does* have these columns, you must invoke the function
+# below in order to merge them into your schema.  you should do this
+# on app startup and they'll be available normally from then on.
+
+RUNTIME = {'added_latest_columns': False}
+
+def use_latest_columns():
+    if RUNTIME['added_latest_columns']:
+        return
+
+    MemberType.ignore_sales = sa.Column('ignoreSales', sa.Boolean(), nullable=True, default=False)
+    MemberType.sales_code = sa.Column('salesCode', sa.Integer(), nullable=True)
+
+    RUNTIME['added_latest_columns'] = True
diff --git a/corepos/db/office_trans/model.py b/corepos/db/office_trans/model.py
index b4659cd..c2b0959 100644
--- a/corepos/db/office_trans/model.py
+++ b/corepos/db/office_trans/model.py
@@ -2,7 +2,7 @@
 ################################################################################
 #
 #  pyCOREPOS -- Python Interface to CORE POS
-#  Copyright © 2018-2024 Lance Edgar
+#  Copyright © 2018-2025 Lance Edgar
 #
 #  This file is part of pyCOREPOS.
 #
@@ -26,7 +26,8 @@ CORE POS Transaction Data Model
 
 import sqlalchemy as sa
 from sqlalchemy import orm
-from sqlalchemy.ext.declarative import declared_attr
+
+from corepos.db.common import trans as common
 
 
 Base = orm.declarative_base()
@@ -68,118 +69,20 @@ class EquityLiveBalance(Base):
     start_date = sa.Column('startdate', sa.DateTime(), nullable=True)
 
 
-class TransactionDetailBase:
+class DTransactionBase(common.TransactionDetailBase):
     """
-    Represents a POS transaction detail record.
+    Base class for ``dtransactions`` and similar models.
     """
-
-    # store
     store_row_id = sa.Column(sa.Integer(), primary_key=True, nullable=False)
-    store_id = sa.Column(sa.Integer(), nullable=True, default=0)
 
-    # register
-    register_number = sa.Column('register_no', sa.Integer(), nullable=True)
     pos_row_id = sa.Column(sa.Integer(), nullable=True)
-
-    # txn
-    transaction_id = sa.Column('trans_id', sa.Integer(), nullable=True)
-    transaction_number = sa.Column('trans_no', sa.Integer(), nullable=True)
-    transaction_type = sa.Column('trans_type', sa.String(length=1), nullable=True)
-    transaction_subtype = sa.Column('trans_subtype', sa.String(length=2), nullable=True)
-
-    trans_status = sa.Column(sa.String(length=1), nullable=True)
-
-    @declared_attr
-    def transaction_status(self):
-        return orm.synonym('trans_status')
-
-    # cashier
-    employee_number = sa.Column('emp_no', sa.Integer(), nullable=True)
-
-    # customer
-    card_number = sa.Column('card_no', sa.Integer(), nullable=True)
-    member_type = sa.Column('memType', sa.Integer(), nullable=True)
-    staff = sa.Column(sa.Boolean(), nullable=True)
-
-    ##############################
-    # remainder is "line item" ...
-    ##############################
-
-    upc = sa.Column(sa.String(length=13), nullable=True)
-
-    department_number = sa.Column('department', sa.Integer(), nullable=True)
-
-    description = sa.Column(sa.String(length=30), nullable=True)
-
-    quantity = sa.Column(sa.Float(), nullable=True)
-
-    scale = sa.Column(sa.Boolean(), nullable=True, default=False)
-
-    cost = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
-
-    unitPrice = sa.Column('unitPrice', sa.Numeric(precision=10, scale=2), nullable=True)
-
-    @declared_attr
-    def unit_price(self):
-        return orm.synonym('unitPrice')
-
-    total = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
-
-    reg_price = sa.Column('regPrice', sa.Numeric(precision=10, scale=2), nullable=True)
-
-    tax = sa.Column(sa.SmallInteger(), nullable=True)
-
-    @declared_attr
-    def tax_rate_id(self):
-        return orm.synonym('tax')
-
-    food_stamp = sa.Column('foodstamp', sa.Boolean(), nullable=True)
-
-    discount = sa.Column(sa.Numeric(precision=10, scale=2), nullable=True)
-
-    member_discount = sa.Column('memDiscount', sa.Numeric(precision=10, scale=2), nullable=True)
-
-    discountable = sa.Column(sa.Boolean(), nullable=True)
-
-    discount_type = sa.Column('discounttype', sa.Integer(), nullable=True)
-
-    voided = sa.Column(sa.Integer(), nullable=True)
-
-    percent_discount = sa.Column('percentDiscount', sa.Integer(), nullable=True)
-
-    item_quantity = sa.Column('ItemQtty', sa.Float(), nullable=True)
-
-    volume_discount_type = sa.Column('volDiscType', sa.Integer(), nullable=True)
-
-    volume = sa.Column(sa.Integer(), nullable=True)
-
-    volume_special = sa.Column('VolSpecial', sa.Numeric(precision=10, scale=2), nullable=True)
-
-    mix_match = sa.Column('mixMatch', sa.String(length=13), nullable=True)
-
-    matched = sa.Column(sa.Boolean(), nullable=True)
-
-    num_flag = sa.Column('numflag', sa.Integer(), nullable=True, default=0)
-
-    char_flag = sa.Column('charflag', sa.String(length=2), nullable=True)
-
-    def __str__(self):
-        return self.description or ''
-
-
-class DTransactionBase(TransactionDetailBase):
-
+    store_id = sa.Column(sa.Integer(), nullable=True, default=0)
     date_time = sa.Column('datetime', sa.DateTime(), nullable=True)
 
 
-class DLogBase(TransactionDetailBase):
-
-    date_time = sa.Column('tdate', sa.DateTime(), nullable=True)
-
-
 class DTransaction(DTransactionBase, Base):
     """
-    Represents a record from ``dtransactions`` table.
+    Data model for ``dtransactions`` table.
     """
     __tablename__ = 'dtransactions'
 
diff --git a/pyproject.toml b/pyproject.toml
index 143843f..cf50f41 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -6,7 +6,7 @@ build-backend = "hatchling.build"
 
 [project]
 name = "pyCOREPOS"
-version = "0.3.4"
+version = "0.5.1"
 description = "Python Interface to CORE POS"
 readme = "README.md"
 authors = [{name = "Lance Edgar", email = "lance@edbob.org"}]