c# - Update a database generated option -

i have ef model class magazine.

i have property magazinecode database generated option (trigger) .

property(o => o.magazinecode).hasdatabasegeneratedoption(databasegeneratedoption.computed); 

when insert new magazine works fine. can retrieve magazinecode after .savechanges() , can send generated magazinecode 3rd party.

i want generate magazine code when insert , after have possibility update.

if try update now, ef makes fun of me must flagged column database generated.

is there way keep column database generated (at insertion) , have possibility update (after insertion) ?