Raw SQL Query without DbSet - Entity Framework Core

Solution 1:

It depends if you're using EF Core 2.1 or EF Core 3 and higher versions.

If you're using EF Core 2.1

If you're using EF Core 2.1 Release Candidate 1 available since 7 may 2018, you can take advantage of the proposed new feature which is Query type.

What is query type?

In addition to entity types, an EF Core model can contain query types, which can be used to carry out database queries against data that isn't mapped to entity types.

When to use query type?

Serving as the return type for ad hoc FromSql() queries.

Mapping to database views.

Mapping to tables that do not have a primary key defined.

Mapping to queries defined in the model.

So you no longer need to do all the hacks or workarounds proposed as answers to your question. Just follow these steps:

First you defined a new property of type DbQuery<T> where T is the type of the class that will carry the column values of your SQL query. So in your DbContext you'll have this:

public DbQuery<SomeModel> SomeModels { get; set; }

Secondly use FromSql method like you do with DbSet<T>:

var result = context.SomeModels.FromSql("SQL_SCRIPT").ToList();
var result = await context.SomeModels.FromSql("SQL_SCRIPT").ToListAsync();

Also note that DdContexts are partial classes, so you can create one or more separate files to organize your 'raw SQL DbQuery' definitions as best suits you.

If you're using EF Core 3.0 and higher versions

Query type is now known as Keyless entity type. As said above query types were introduced in EF Core 2.1. If you're using EF Core 3.0 or higher version you should now consider using keyless entity types because query types are now marked as obsolete.

This feature was added in EF Core 2.1 under the name of query types. In EF Core 3.0 the concept was renamed to keyless entity types. The [Keyless] Data Annotation became available in EFCore 5.0.

We still have the same scenarios as for query types for when to use keyless entity type.

So to use it you need to first mark your class SomeModel with [Keyless] data annotation or through fluent configuration with .HasNoKey() method call like below:

public DbSet<SomeModel> SomeModels { get; set; }

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    modelBuilder.Entity<SomeModel>().HasNoKey();
}

After that configuration, you can use one of the methods explained here to execute your SQL query. For example you can use this one:

var result = context.SomeModels.FromSqlRaw("SQL SCRIPT").ToList();
var result = await context.SomeModels.FromSql("SQL_SCRIPT").ToListAsync();

Solution 2:

Building on the other answers I've written this helper that accomplishes the task, including example usage:

public static class Helper
{
    public static List<T> RawSqlQuery<T>(string query, Func<DbDataReader, T> map)
    {
        using (var context = new DbContext())
        {
            using (var command = context.Database.GetDbConnection().CreateCommand())
            {
                command.CommandText = query;
                command.CommandType = CommandType.Text;

                context.Database.OpenConnection();

                using (var result = command.ExecuteReader())
                {
                    var entities = new List<T>();

                    while (result.Read())
                    {
                        entities.Add(map(result));
                    }

                    return entities;
                }
            }
        }
    }

Usage:

public class TopUser
{
    public string Name { get; set; }

    public int Count { get; set; }
}

var result = Helper.RawSqlQuery(
    "SELECT TOP 10 Name, COUNT(*) FROM Users U"
    + " INNER JOIN Signups S ON U.UserId = S.UserId"
    + " GROUP BY U.Name ORDER BY COUNT(*) DESC",
    x => new TopUser { Name = (string)x[0], Count = (int)x[1] });

result.ForEach(x => Console.WriteLine($"{x.Name,-25}{x.Count}"));

I plan to get rid of it as soon as built-in support is added. According to a statement by Arthur Vickers from the EF Core team it is a high priority for post 2.0. The issue is being tracked here.

Solution 3:

In EF Core you no longer can execute "free" raw sql. You are required to define a POCO class and a DbSet for that class. In your case you will need to define Rank:

var ranks = DbContext.Ranks
   .FromSql("SQL_SCRIPT OR STORED_PROCEDURE @p0,@p1,...etc", parameters)
   .AsNoTracking().ToList();

As it will be surely readonly it will be useful to include the .AsNoTracking() call.

EDIT - Breaking change in EF Core 3.0:

DbQuery() is now obsolete, instead DbSet() should be used (again). If you have a keyless entity, i.e. it don't require primary key, you can use HasNoKey() method:

ModelBuilder.Entity<SomeModel>().HasNoKey()

More information can be found here

Solution 4:

For now, until there is something new from EFCore I would used a command and map it manually

  using (var command = this.DbContext.Database.GetDbConnection().CreateCommand())
  {
      command.CommandText = "SELECT ... WHERE ...> @p1)";
      command.CommandType = CommandType.Text;
      var parameter = new SqlParameter("@p1",...);
      command.Parameters.Add(parameter);

      this.DbContext.Database.OpenConnection();

      using (var result = command.ExecuteReader())
      {
         while (result.Read())
         {
            .... // Map to your entity
         }
      }
  }

Try to SqlParameter to avoid Sql Injection.

 dbData.Product.FromSql("SQL SCRIPT");

FromSql doesn't work with full query. Example if you want to include a WHERE clause it will be ignored.

Some Links:

Executing Raw SQL Queries using Entity Framework Core

Raw SQL Queries