How can I attach a PDF file to a DB record in SQL with C #?

It does not really matter what version of the IDE you use, with C # you can do many things, and among them you can choose to serialize the file (PDF or any other) to a Base64 string and save it as if it were a string:

using System;
using System.IO;

public class Serializador
{
    public static bool GuardarArchivo(string archivo)
    {
        // Leemos todos los bytes del archivo y luego lo guardamos como Base64 en un string.
        string resultado = Convert.ToBase64String(File.ReadAllBytes(archivo));

        using (var cn = 
            new SqlConnection(ConfigurationManager.ConnectionStrings[0].ConnectionString))
        {
            using(var cmd = cn.CreateCommand())
            {
                // Se invoca a un StoreProcedure para insertar el registro.
                cmd.CommandText = "usp_InsertArchivo";
                cmd.CommandType = CommandType.StoreProcedure;
                // Con la ayuda de FileInfo devolvemos unicamente el nombre del archivo.
                cmd.Parameters.AddWithValue("@nombreArchivo", new FileInfo(archivo).Name);
                // El resultado serializado del archivo pasa como un varchar cualquiera.
                cmd.Parameters.AddWithValue("@contenido", resultado);

                cn.Open();

                int cantidad = cmd.ExecuteNonQuery();

                // Si es mayor a 0 entonces se guardo correctamente.
                return (cantidad > 0);
            }
        }
    }

}

Yes, it is possible. You have three alternatives:

Each alternative has its pros and cons after several discussions about it. The most recommended I've seen for SQL Server (at least on images, but applies to any type of file) is the second . In case you do not use SQL Server, the second option is discarded and I would recommend the third because it facilitates the maintenance of the files, the database is not so heavy, there is separation of issues, facilitates testing, etc.

Here is more information: link

If possible, although it is not recommended

You can declare your column as VARBINARY in Sql

And the code to upload the file would be more or less would be something like this:

byte[] byteArray = cargarArchivo(); //Regresa tu archivo como un arreglo de bytes
var command = new SqlCommand("Insert Into Tu_Tabla columna_archivo Values (@archivo)" , sqlConection); // Creamos un SqlCommand que tenga un insert comun, pero apuntando a la columna
command.Parameters.Add("@archivo", SqlDbType.VarBinary, byteArray.Length).Value = byteArray; //Pasamos la referencia del arreglo de bytes
command.ExecuteNonQuery();// Y ejecutamos el query sin retorno

Working with files within the database is not a very good practice, since inserts and requests are more expensive than simple text or some other numerical type. But if possible.

Here you touch that topic in English, take a look;)

Here

[ASP.NET] Burn file on base of data

I explain how you could insert a file into a field in the table

As you will see, a field of type varbinary is defined in the table and to insert you must pass a parameter array to INSERT .

If your application is winforms it's very simple just use the File.ReadAllBytes ()

In the link example, the useful code is in the persistence layer

    public static void Guardar(string nombrearchivo, int length, byte[] archivo)
    {
        using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["default"].ToString()))
        {
            conn.Open();

            string query = @"INSERT INTO Archivos (nombre, length, archivo)
                             VALUES (@name, @length, @archivo)";

            SqlCommand cmd = new SqlCommand(query, conn);

            cmd.Parameters.AddWithValue("@name", nombrearchivo);
            cmd.Parameters.AddWithValue("@length", length);

            SqlParameter archParam = cmd.Parameters.Add("@archivo", SqlDbType.VarBinary);
            archParam.Value = archivo;

            cmd.ExecuteNonQuery();

        }

    }

generating a parameter in the INSERT that allows assigning the byte [] of the file

I would also recommend values if you find it useful to define the field as FileStream , for the version of Sql Server that you mention you can use it and it is more optimal when registering files in the db.

An Introduction to SQL Server FileStream

How Do I: Use SQL File Stream