c# - Include with FromSqlRaw and stored procedure in EF Core 3.1

Question

So here's the deal - I am currently using EF Core 3.1 and let's say I have an entity:

public class Entity
{
    public int Id { get; set; }
    public int AnotherEntityId { get; set; }
    public virtual AnotherEntity AnotherEntity { get; set; }
}

When I access the DbSet<Entity> Entities normal way, I include AnotherEntity like:

_context.Entities.Include(e => e.AnotherEntity)

and this works. Why wouldn't it, right? Then I go with:

_context.Entities.FromSqlRaw("SELECT * FROM Entities").Include(e => e.AnotherEntity)

and this also works. Both return me the same collection of objects joined with AnotherEntity. Then I use a stored procedure which consists of the same query SELECT * FROM Entities named spGetEntities:

_context.Entities.FromSqlRaw("spGetEntities")

guess what? This also works. It gives me the same output but without joined AnotherEntity, obviously. However if I try to add the Include like this:

_context.Entities.FromSqlRaw("spGetEntities").Include(e => e.AnotherEntity)

I am getting:

FromSqlRaw or FromSqlInterpolated was called with non-composable SQL and with a query composing over it. Consider calling AsEnumerable after the FromSqlRaw or FromSqlInterpolated method to perform the composition on the client side.

Even though the output of _context.Entities.FromSqlRaw("SELECT * FROM Entities") and _context.Entities.FromSqlRaw("spGetEntities") is identical.

I couldn't find a proof that I can or I can not do this with EF Core 3.1 but if someone could give me any hint of possibility of this approach it would be nice.

Also if there is another way to get joined entities using stored procedure I would probably accept it as the solution of my issue.

Answer 1

Shortly, you can't do that (at least for SqlServer). The explanation is contained in EF Core documentation - Raw SQL Queries - Composing with LINQ:

Composing with LINQ requires your raw SQL query to be composable since EF Core will treat the supplied SQL as a subquery. SQL queries that can be composed on begin with the SELECT keyword. Further, SQL passed shouldn't contain any characters or options that aren't valid on a subquery, such as:

• A trailing semicolon
• On SQL Server, a trailing query-level hint (for example, OPTION (HASH JOIN))
• On SQL Server, an ORDER BY clause that isn't used with OFFSET 0 OR TOP 100 PERCENT in the SELECT clause

SQL Server doesn't allow composing over stored procedure calls, so any attempt to apply additional query operators to such a call will result in invalid SQL. Use AsEnumerable or AsAsyncEnumerable method right after FromSqlRaw or FromSqlInterpolated methods to make sure that EF Core doesn't try to compose over a stored procedure.

Additionally, since Include / ThenInclude require EF Core IQueryable<>, AsEnumerable / AsAsyncEnumerable etc. is not an option. You really need composable SQL, hence stored procedures are no option.

Instead of stored procedures though, you can use Table-Valued Functions (TVF) or database views because they are composable (select * from TVF(params) or select * from db_view) .