diff --git a/app/migrations/versions/150252c1cdb1_.py b/app/migrations/versions/150252c1cdb1_.py
index 753b70d..927c101 100644
--- a/app/migrations/versions/150252c1cdb1_.py
+++ b/app/migrations/versions/150252c1cdb1_.py
@@ -5,6 +5,7 @@ Revises: None
 Create Date: 2019-04-02 18:00:12.618368
 
 """
+# pylint: disable=invalid-name
 
 # revision identifiers, used by Alembic.
 revision = "150252c1cdb1"
diff --git a/app/migrations/versions/9159a6fed021_initial_haldis_support.py b/app/migrations/versions/9159a6fed021_initial_haldis_support.py
index 03551b2..4c9bdc0 100644
--- a/app/migrations/versions/9159a6fed021_initial_haldis_support.py
+++ b/app/migrations/versions/9159a6fed021_initial_haldis_support.py
@@ -5,83 +5,139 @@ Revises: 150252c1cdb1
 Create Date: 2020-01-26 16:22:00.935963
 
 """
+# pylint: disable=invalid-name
 
 # revision identifiers, used by Alembic.
-revision = '9159a6fed021'
-down_revision = '150252c1cdb1'
+revision = "9159a6fed021"
+down_revision = "150252c1cdb1"
 
+from itertools import chain
 from alembic import op
 import sqlalchemy as sa
+from sqlalchemy.sql import table, column, text
+
+from hlds.definitions import location_definitions
+from data.migration import LOCATION_LEGACY_TO_HLDS, DISH_LEGACY_TO_HLDS
 
 
 def upgrade():
-    # ### commands auto generated by Alembic - please adjust! ###
-    op.create_table('order_item_choice',
-    sa.Column('id', sa.Integer(), nullable=False),
-    sa.Column('choice_id', sa.String(length=64), nullable=True),
-    sa.Column('order_item_id', sa.Integer(), nullable=False),
-    sa.Column('kind', sa.String(length=1), nullable=False),
-    sa.Column('name', sa.String(length=120), nullable=True),
-    sa.Column('value', sa.String(length=120), nullable=True),
-    sa.ForeignKeyConstraint(['order_item_id'], ['order_item.id'], ),
-    sa.PrimaryKeyConstraint('id')
+    # First the simple actions
+    op.create_table("order_item_choice",
+        sa.Column("id", sa.Integer(), nullable=False),
+        sa.Column("choice_id", sa.String(length=64), nullable=True),
+        sa.Column("order_item_id", sa.Integer(), nullable=False),
+        sa.Column("kind", sa.String(length=1), nullable=False),
+        sa.Column("name", sa.String(length=120), nullable=True),
+        sa.Column("value", sa.String(length=120), nullable=True),
+        sa.ForeignKeyConstraint(["order_item_id"], ["order_item.id"], ),
+        sa.PrimaryKeyConstraint("id")
     )
-    op.drop_table('product')
-    op.drop_table('location')
-    op.add_column('order', sa.Column('courier_id', sa.Integer(), nullable=True))
-    op.add_column('order', sa.Column('location_name', sa.String(length=128), nullable=True))
-    op.drop_constraint(None, 'order', type_='foreignkey')
-    op.drop_column('order', 'courrier_id')
-    op.add_column('order_item', sa.Column('comment', sa.Text(), nullable=True))
-    op.add_column('order_item', sa.Column('dish_id', sa.String(length=120), nullable=True))
-    op.add_column('order_item', sa.Column('dish_name', sa.String(length=120), nullable=True))
-    op.add_column('order_item', sa.Column('hlds_data_version', sa.String(length=40), nullable=True))
-    op.add_column('order_item', sa.Column('price', sa.Integer(), nullable=False))
-    op.add_column('order_item', sa.Column('user_name', sa.String(length=120), nullable=True))
-    op.alter_column('order_item', 'paid',
-               existing_type=sa.BOOLEAN(),
-               nullable=False)
-    op.drop_constraint(None, 'order_item', type_='foreignkey')
-    op.drop_column('order_item', 'product_id')
-    op.drop_column('order_item', 'name')
-    op.drop_column('order_item', 'extra')
-    # ### end Alembic commands ###
+    op.add_column("order_item", sa.Column("hlds_data_version", sa.String(length=40), nullable=True))
+    op.alter_column("order_item", "paid", existing_type=sa.BOOLEAN(), nullable=False)
+    op.alter_column("order", "courrier_id", new_column_name="courier_id")
+    op.alter_column("order_item", "extra", new_column_name="comment",
+                    existing_type=sa.String(254), type_=sa.Text())
+    op.alter_column("order_item", "name", new_column_name="user_name")
+
+    #----------------------------------------------------------------------------------------------
+    # Migrate historical product data to order items
+
+    # First create the new columns we will populate
+    op.add_column("order_item", sa.Column("dish_id", sa.String(length=64), nullable=True))
+    op.add_column("order_item", sa.Column("dish_name", sa.String(length=120), nullable=True))
+    op.add_column("order_item", sa.Column("price", sa.Integer(), nullable=False))
+    # Brief, ad-hoc table constructs just for our UPDATE statement, see
+    # https://alembic.sqlalchemy.org/en/latest/ops.html#alembic.operations.Operations.execute
+    order_item = table("order_item",
+        column("product_id", sa.Integer),
+        column("dish_id", sa.String),
+        column("dish_name", sa.String),
+        column("price", sa.Integer)
+    )
+    # Construct and execute queries
+    new_dish_id = [
+        order_item.update()
+            .where(order_item.c.product_id == old_id)
+            .values(dish_id=new_id)
+        for old_id, new_id in DISH_LEGACY_TO_HLDS.items()
+    ]
+    dish_name_and_price_from_product = text("""
+        UPDATE order_item
+        SET dish_name = (SELECT name  FROM product WHERE product.id == order_item.product_id),
+            price     = (SELECT price FROM product WHERE product.id == order_item.product_id)"""
+    )
+    for query in chain(new_dish_id, [dish_name_and_price_from_product]):
+        op.execute(query)
+    # Historical product data migrated, drop obsolete column and table
+    op.drop_constraint(None, "order_item", type_="foreignkey")
+    op.drop_column("order_item", "product_id")
+    op.drop_table("product")
+
+    #----------------------------------------------------------------------------------------------
+    # Migrate historical location data to orders
+
+    op.add_column("order", sa.Column("location_name", sa.String(length=128), nullable=True))
+    op.alter_column("order", "location_id", new_column_name="legacy_location_id")
+    # Brief, ad-hoc table constructs just for our UPDATE statement, see
+    # https://alembic.sqlalchemy.org/en/latest/ops.html#alembic.operations.Operations.execute
+    order = table("order",
+        column("legacy_location_id", sa.Integer),
+        column("location_id", sa.String),
+        column("location_name", sa.String)
+    )
+    # Construct and execute queries
+    new_location_id = [
+        order.update()
+            .where(order.c.legacy_location_id == old_id)
+            .values(location_id=new_id)
+        for old_id, new_id in LOCATION_LEGACY_TO_HLDS.items()
+    ]
+    location_name_from_location = text("""
+        UPDATE order
+        SET location_name = (SELECT name FROM location
+                             WHERE location.id == order.legacy_location_id)"""
+    )
+    for query in chain(new_location_id, [location_name_from_location]):
+        op.execute(query)
+    # Historical location data migrated, drop obsolete column and table
+    op.drop_column("order", "legacy_location_id")
+    op.drop_constraint(None, "order", type_="foreignkey")
+    op.drop_table("location")
 
 
 def downgrade():
+    "Don't use this. It will cripple the data."
+
+    op.alter_column("order_item", "paid", existing_type=sa.Boolean(), nullable=True)
+    op.alter_column("order", "courier_id", new_column_name="courrier_id")
+    op.alter_column("order_item", "comment", new_column_name="extra",
+                    existing_type=sa.Text(), type_=sa.String(254))
+    op.alter_column("order_item", "user_name", new_column_name="name")
+
     # ### commands auto generated by Alembic - please adjust! ###
-    op.add_column('order_item', sa.Column('extra', sa.VARCHAR(length=254), nullable=True))
-    op.add_column('order_item', sa.Column('name', sa.VARCHAR(length=120), nullable=True))
-    op.add_column('order_item', sa.Column('product_id', sa.INTEGER(), nullable=True))
-    op.create_foreign_key(None, 'order_item', 'product', ['product_id'], ['id'])
-    op.alter_column('order_item', 'paid',
-               existing_type=sa.BOOLEAN(),
-               nullable=True)
-    op.drop_column('order_item', 'user_name')
-    op.drop_column('order_item', 'price')
-    op.drop_column('order_item', 'hlds_data_version')
-    op.drop_column('order_item', 'dish_name')
-    op.drop_column('order_item', 'dish_id')
-    op.drop_column('order_item', 'comment')
-    op.add_column('order', sa.Column('courrier_id', sa.INTEGER(), nullable=True))
-    op.create_foreign_key(None, 'order', 'location', ['location_id'], ['id'])
-    op.drop_column('order', 'location_name')
-    op.drop_column('order', 'courier_id')
-    op.create_table('location',
-    sa.Column('id', sa.INTEGER(), nullable=False),
-    sa.Column('name', sa.VARCHAR(length=120), nullable=False),
-    sa.Column('address', sa.VARCHAR(length=254), nullable=True),
-    sa.Column('website', sa.VARCHAR(length=120), nullable=True),
-    sa.Column('telephone', sa.VARCHAR(length=20), nullable=True),
-    sa.PrimaryKeyConstraint('id')
+    op.add_column("order_item", sa.Column("product_id", sa.INTEGER(), nullable=True))
+    op.create_foreign_key(None, "order_item", "product", ["product_id"], ["id"])
+    op.drop_column("order_item", "price")
+    op.drop_column("order_item", "hlds_data_version")
+    op.drop_column("order_item", "dish_name")
+    op.drop_column("order_item", "dish_id")
+    op.create_foreign_key(None, "order", "location", ["location_id"], ["id"])
+    op.drop_column("order", "location_name")
+    op.create_table("location",
+        sa.Column("id", sa.INTEGER(), nullable=False),
+        sa.Column("name", sa.VARCHAR(length=120), nullable=False),
+        sa.Column("address", sa.VARCHAR(length=254), nullable=True),
+        sa.Column("website", sa.VARCHAR(length=120), nullable=True),
+        sa.Column("telephone", sa.VARCHAR(length=20), nullable=True),
+        sa.PrimaryKeyConstraint("id")
     )
-    op.create_table('product',
-    sa.Column('id', sa.INTEGER(), nullable=False),
-    sa.Column('location_id', sa.INTEGER(), nullable=True),
-    sa.Column('name', sa.VARCHAR(length=120), nullable=False),
-    sa.Column('price', sa.INTEGER(), nullable=False),
-    sa.ForeignKeyConstraint(['location_id'], ['location.id'], ),
-    sa.PrimaryKeyConstraint('id')
+    op.create_table("product",
+        sa.Column("id", sa.INTEGER(), nullable=False),
+        sa.Column("location_id", sa.INTEGER(), nullable=True),
+        sa.Column("name", sa.VARCHAR(length=120), nullable=False),
+        sa.Column("price", sa.INTEGER(), nullable=False),
+        sa.ForeignKeyConstraint(["location_id"], ["location.id"], ),
+        sa.PrimaryKeyConstraint("id")
     )
-    op.drop_table('order_item_choice')
+    op.drop_table("order_item_choice")
     # ### end Alembic commands ###
diff --git a/app/models/orderitem.py b/app/models/orderitem.py
index 49ebb34..1e6a5f3 100644
--- a/app/models/orderitem.py
+++ b/app/models/orderitem.py
@@ -12,7 +12,7 @@ class OrderItem(db.Model):
     order_id = db.Column(db.Integer, db.ForeignKey("order.id"), nullable=False)
     user_id = db.Column(db.Integer, db.ForeignKey("user.id"))
     user_name = db.Column(db.String(120))
-    dish_id = db.Column(db.String(120), nullable=True)
+    dish_id = db.Column(db.String(64), nullable=True)
     dish_name = db.Column(db.String(120), nullable=True)
     price = db.Column(db.Integer, nullable=False)
     paid = db.Column(
diff --git a/data/migration.py b/data/migration.py
index c5fee0d..bab0094 100644
--- a/data/migration.py
+++ b/data/migration.py
@@ -1,4 +1,4 @@
-LEGACY_TO_HLDS_TRANSLATION = {
+LOCATION_LEGACY_TO_HLDS = {
     2: "blauw_kotje",
     3: "ocean_garden",
     4: "delhaize",
@@ -26,3 +26,7 @@ LEGACY_TO_HLDS_TRANSLATION = {
     29: "fitchen",
     30: "kebab_anadolu",
 }
+
+DISH_LEGACY_TO_HLDS = {
+    # TODO
+}