EntitySet Clear followed by Add results in duplicate entries
Posted: Thu 17 Sep 2015 17:15
I am seeing an issue similar to: http://forums.devart.com/viewtopic.php? ... set#p72059
I have a business object which has the desired list of computer groups. My strategy to sync the EntitySet to the business object list is to .Clear() the EntitySet and then re-add each desired computer group.
However this results in duplicate entries (in cases where there should be an effective 'remove' of one of the elements), since no DELETE is ever generated to correspond with the .Clear() call. All that is generated is the UPDATE for the e_Policy and an INSERT for the EntitySet e_ComputerGroups.
I have used other ORMs and they support Clear() followed by re-adding the desired entries.
I could workaround this by manually calculating for each desired entry, whether it would result in an add or delete by comparing the current EntitySet list. Or I could SubmitChanges after calling Clear(), but that is not desirable because it creates a whole new set of problems by submitting changes midway through a possibly complex business transaction.
Can you advise if this behavior is a bug? It seems like an ORM should be able to handle the case of figuring out the SQL required to cause the database to match the ORM objects after simple manipulation of those ORM objects. Isn't this the whole point of an ORM?
Thanks
Craig
results in:
Begin transaction
Execute:
UPDATE public.policies SET date_modified = :p1 WHERE id = :key1;
INSERT INTO public.policy_to_computer_groups (computer_group_id, policy_id) VALUES (:p2, :p3);
Expected a DELETE to correspond to entries that were effectively removed as a result of the Clear() and re-add of EntitySet members.
Below is my my code. I get the entity e_Policy, which has an EntitySet of e_ComputerGroup named ComputerGroups.>> if ...delete/add several items from EntitySet LinqConnect generates an Update statement for Entity A but only generates the Insert statements for EntitySet not the delete statements.
I have a business object which has the desired list of computer groups. My strategy to sync the EntitySet to the business object list is to .Clear() the EntitySet and then re-add each desired computer group.
However this results in duplicate entries (in cases where there should be an effective 'remove' of one of the elements), since no DELETE is ever generated to correspond with the .Clear() call. All that is generated is the UPDATE for the e_Policy and an INSERT for the EntitySet e_ComputerGroups.
I have used other ORMs and they support Clear() followed by re-adding the desired entries.
I could workaround this by manually calculating for each desired entry, whether it would result in an add or delete by comparing the current EntitySet list. Or I could SubmitChanges after calling Clear(), but that is not desirable because it creates a whole new set of problems by submitting changes midway through a possibly complex business transaction.
Can you advise if this behavior is a bug? It seems like an ORM should be able to handle the case of figuring out the SQL required to cause the database to match the ORM objects after simple manipulation of those ORM objects. Isn't this the whole point of an ORM?
Thanks
Craig
Code: Select all
e_Policy pol = GetPolicyById(bo.IdGuid.ToString(), ctx);
// sync the DAL from the business object
pol.DateModified = DateTime.UtcNow;
// Sync the EntitySet by clearing and re-adding desired entities from business object
pol.e_ComputerGroups.Clear();
foreach (var group in bo.ComputerGroups)
{
e_ComputerGroup groupToAdd = e_ComputerGroup.GetComputerGroupById(group.IdGuid.ToString(), ctx);
pol.e_ComputerGroups.Add(groupToAdd);
}
ctx.SubmitChanges();
Begin transaction
Execute:
UPDATE public.policies SET date_modified = :p1 WHERE id = :key1;
INSERT INTO public.policy_to_computer_groups (computer_group_id, policy_id) VALUES (:p2, :p3);
Expected a DELETE to correspond to entries that were effectively removed as a result of the Clear() and re-add of EntitySet members.