Как узнать id вставленной строки

SELECT @@IDENTITY

DataTable myTable = new DataTable();

myTable.Columns.Add("Id", System.Type.GetType("System.Int32"));
myTable.Columns.Add("Value", System.Type.GetType("System.String"));

for (int i = 0; i < 23; i++)
{
	DataRow dr = myTable.NewRow();
	dr[0] = i;
	dr[1] = "val" + i.ToString();
	myTable.Rows.Add(dr);
}

string strFilter = "Id = " + myTable.Rows[myTable.Rows.Count-1].ItemArray[0].ToString();
string strSort = "Id";
DataRow[] foundRows;
foundRows = myTable.Select(strFilter, strSort);

SqlCommand cmd=new SqlCommand("INSERT INTO T34 (nm) VALUES('петя'); SELECT SCOPE_IDENTITY();", cn);
decimal id=(decimal)cmd.ExecuteScalar();