When I update my database schema with drush entity-updates. I get an error When I try to update my database Schema I'm getting the following error:


  Drupal\Core\Entity\Exception\FieldStorageDefinitionUpdateForbiddenException:[error]
  The SQL storage cannot change the schema for an existing field
  (order_total in uc_order entity) with data. in
  Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema->updateSharedTableSchema()
  (line 1376 of
  /www/htdocs/xxx/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php).
  Failed:                                                              [error]
  Drupal\Core\Entity\Exception\FieldStorageDefinitionUpdateForbiddenException:
  !message in
  Drupal\Core\Entity\Sql\SqlContentEntityStorageSchema-&gt;updateSharedTableSchema()
  (line 1376 of
  /www/htdocs/xxx/core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorageSchema.php).


What can I do?
Sounds like you are trying to update existing field order_total in uc_order. You can't update it since you have some data in it already. Remove content that uses it (orders), and try again.

Also note that drush entity:updates currently doesn't support all changes (e.g. changing table keys). See this Change Record for information on providing a hook_update(): https://www.drupal.org/node/2554097