在EF Core 2.1中的DbContext上执行RAW SQL

Question

I have researched this and always found examples like this:

var blogs = context.Blogs
    .FromSql("SELECT * FROM dbo.Blogs")
    .ToList();

The problem is, I don't want to run my raw SQL on the Blogs table. Basically, I want to implement an interface like this:

bool ExecuteNonSafeSql(
    string connectionString,
    string sql);

Is there a way to do that with DbContext?

Answer 1

At the time of writing (EF Core 2.1), there is no way to execute arbitrary secuence returning SQL command.

Only entity types and Query Types are supported via FromSql .

So the closest solution is to define query type (a class holding the query result) and use FromSql , but it's not generic - the query types must be registered in the DbContext via fluent API and the method should receive a generic argument specifying that type, eg

class ResultType
{
   // ...
}

then

modelBuilder.Query<ResultType>();

and finally

db.Query<ResultType>().FromSql(...)

Note that Database.ExecuteSqlCommand can execute arbitrary SQL, but can't be used to return sequence ( IEnumerable<T> , IQueryable<T> ).

Answer 2

You can use context.Database.ExecuteSqlCommand() to execute sql.

If you want to use SqlCommand you can get the connection by

var cnn = (SqlConnection) context.Database.GetDbConnection();
cnn.Open();
using (var cmd = new SqlCommand(sql, cnn))
using (var rdr = cmd.ExecuteReader(CommandBehavior.SingleResult))

Answer 3

You can use Database.SqlQuery() directly to context.

Here i create a generic function that can execute your query directly with target to Database rather than entity.

public static List<T> Execute<T>(MyDbContext context, string query) where T : class
{
    var result = context.Database
                        .SqlQuery<T>(query)
                        .ToList();

    return result;
}

You can use above function like

var blogs = Execute<Blog>(context, "SELECT * FROM dbo.Blogs");