EF Core - Ignore field (do not create a column in db) but fill it from raw query

Question

I have an entity with a field that should not be created in the database, but should be filled from a stored procedure.

public class Item 
{
    public int Id {get; set;}
    public int CalculatedField {get; set;}
}

Then I want to fill it with a stored procedure

var items = _db.Items.FromSqlRaw("select * from StoredProcedure()").ToList()

But if I use [NotMapped] attribute or .Ignore fluent option - the EF the field completely, and even though my stored procedure returns CalculatedField, EF does not use it.

Is there any way to achieve this behavior?

What do you mean by "EF does not use it" ? How are you expecting EF to use the not mapped property? — devlin carnate, Jun 17 '20 at 18:58
@devlincarnate I want to find a way to not create a field in DB, but just fill it from rawQuery — Anarion, Jun 17 '20 at 19:03
So, what's preventing you from doing that? Does your raw query not return the value for the field? — devlin carnate, Jun 17 '20 at 19:07
@devlincarnate it returns it (if I execute it in DB), but EF doesn't map the field to storedProccedure result, because it's [NotMapped] — Anarion, Jun 17 '20 at 19:09
You get to do that yourself...create an instance of the class, and assign the property value from the query result. If you have a list of objects, then do it in a loop. Or using a LINQ or Lambda — devlin carnate, Jun 17 '20 at 19:11
@devlincarnate found a bit better solution, will post a reply soon. — Anarion, Jun 17 '20 at 19:13
@datwelk, I think I used another model to be mapped to the stored procedure result — Anarion, Feb 02 '21 at 23:03

score 1 · Answer 1 · answered Jun 18 '20 at 15:31

You can use the query results to assign the value. There are various ways in which to do that. Here's one, where you iterate over the query results and instantiate an Item, assign property values and add it to a list of Items:

var items = new List<Item>();
var results = _db.Items.FromSqlRaw("select * from StoredProcedure()").ToList();
foreach(var result in results) {
   var item = new Item {
      Id = result.Id,
      CalculatedField = result.CalculatedField
   }
   items.Add(item);
}

EF Core - Ignore field (do not create a column in db) but fill it from raw query

1 Answers1