如何插入/更新部分映射到视图的实体框架实体？

Question

I have a database with an 'Equipment' table and a view called 'EquipmentStatuses' that does something complicated to associate each entry in the 'Equipment' table to some aggregated value from another table and returns a simple 2 column view with the EquipmentId and a calculated value.

I have mapped the 'Equipment' table to an Equipment entity and created one extra scalar field that maps to the calculated field from the View. It all works fine when I just retrieve records from the database, but when I try to insert or update the Equipment table I get an error from Entity Framework:

Unable to update the EntitySet 'EquipmentStatuses' because it has a DefiningQuery and no <InsertFunction> element exists in the <ModificationFunctionMapping> element to support the current operation.

It seems that entity framework is trying to insert something into the view, but fails because I haven't actually told EF how to do that. However, the single field from the view doesn't need to be updated because it's calculated automatically from another table.

Is there a way to tell entity framework to ignore the view and just update the Equipment table without writing all sorts of boilerplate insert/update/delete stored procedures?

I'm using EF6 with a SQL Server database.

Answer 1

You can detach that object from the context:

dbContext.Entry(EquipmentStatuses).State = EntityState.Detached;

If this is MVC you could also compose viewmodels, send them to the view and then map them back to the proper entities on the POST. A tool like Automapper is great for this.