Migrate modified field on games table

migrations/versions/eaa992d1469b_make_updated_field_nullable.py

@@ -0,0 +1,45 @@
+"""make updated field nullable
+
+Revision ID: eaa992d1469b
+Revises: 
+Create Date: 2020-07-04 18:08:31.035209
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "eaa992d1469b"
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    tables = {
+        "modified": "cities",
+        "modified": "games",
+        "cancel_date": "games",
+        "modified": "payments",
+        "modified": "player_availabilities",
+        "modified": "player_cancel_games",
+        "modified": "purchase_games",
+        "modified": "sports",
+        "modified": "teams",
+        "modified": "user_ratings",
+        "modified": "venues",
+        "updated": "venue_images",
+        "updated": "web_bookings",
+    }
+    for field, table in tables.items():
+        with op.batch_alter_table(table) as batch_op:
+            batch_op.alter_column(column_name=field, nullable=True)
+        query = "UPDATE {0} SET {1} = NULL WHERE {1} = '0000-00-00 00:00:00'".format(
+            table, field
+        )
+        op.execute(query)
+
+
+def downgrade():
+    pass