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

If possible. You have three alternatives:

1. Store file directly in database as type Bloband store binary directly.

2. Store file directly in database with type FileStream.

3. Store the file on disk and store the file path in a field of your table in the database.

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 it applies to any type of file) is the second . In case you do not use SQL Server, the second option is ruled out and I would recommend the third because it facilitates the maintenance of the files, the database is not so heavy, there is a separation of issues, it facilitates the tests, etc.

Here more information about it: https://stackoverflow.com/q/3748/1065197

Yes it is possible, although it is not recommended

You can declare your column like VARBINARYin Sql

And the code to upload the file would be more or less 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 numeric type. But if it is possible.

This topic is touched on in English here, take a look ;)

It doesn't 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 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);
            }
        }
    }

}

Here

[ASP.NET] Save File to Database

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

As you can see, a field of the type is defined in the table varbinaryand to insert you must pass INSERTan array of bytes as a parameter.

If your app is winformsvery simple you just use the File.ReadAllBytes ()

In the example of the link the code that is useful 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 validations if it is not useful for you to define the field as FileStream, for the version Sql Serveryou 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