diff --git a/corepos/db/office_op/model.py b/corepos/db/office_op/model.py
index 68627c0..6087f67 100644
--- a/corepos/db/office_op/model.py
+++ b/corepos/db/office_op/model.py
@@ -1636,7 +1636,9 @@ class BatchType(Base):
     """
     __tablename__ = 'batchType'
 
-    id = sa.Column('batchTypeID', sa.Integer(), primary_key=True, autoincrement=False, nullable=False)
+    # nb. this is *not* autoincrement for some reason; must
+    # calculate new ID manually based on max existing
+    id = sa.Column('batchTypeID', sa.Integer(), nullable=False, primary_key=True, autoincrement=False)
 
     description = sa.Column('typeDesc', sa.String(length=50), nullable=True)
 
@@ -1661,9 +1663,6 @@ class Batch(Base):
     Represents a batch.
     """
     __tablename__ = 'batches'
-    __table_args__ = (
-        sa.ForeignKeyConstraint(['batchType'], ['batchType.batchTypeID']),
-    )
 
     id = sa.Column('batchID', sa.Integer(), primary_key=True, autoincrement=True, nullable=False)
 
@@ -1673,7 +1672,8 @@ class Batch(Base):
 
     name = sa.Column('batchName', sa.String(length=80), nullable=True)
 
-    batch_type_id = sa.Column('batchType', sa.Integer(), nullable=True)
+    batch_type_id = sa.Column('batchType', sa.Integer(),
+                              sa.ForeignKey('batchType.batchTypeID'), nullable=True)
     batch_type = orm.relationship(BatchType)
 
     discount_type = sa.Column('discountType', sa.Integer(), nullable=True)
@@ -1695,16 +1695,18 @@ class BatchItem(Base):
     Represents a batch "list" item.
     """
     __tablename__ = 'batchList'
-    __table_args__ = (
-        sa.ForeignKeyConstraint(['batchID'], ['batches.batchID']),
-    )
 
     id = sa.Column('listID', sa.Integer(), primary_key=True, autoincrement=True, nullable=False)
 
-    batch_id = sa.Column('batchID', sa.Integer(), nullable=True)
+    batch_id = sa.Column('batchID', sa.Integer(),
+                         sa.ForeignKey('batches.batchID'), nullable=True)
     batch = orm.relationship(Batch, backref=orm.backref('items'))
 
     upc = sa.Column(sa.String(length=13), nullable=True)
+    product = orm.relationship(
+        Product,
+        primaryjoin=Product.upc == upc,
+        foreign_keys=[upc])
 
     sale_price = sa.Column('salePrice', sa.Numeric(precision=9, scale=3), nullable=True)