Exportando dados de uma tabela SQL - Update e Inser

Hoje no forum da MSDN postaram uma uma dúvida de como exportar dados de uma tabela do banco de dados SQL Server e gerar um script para inserção e atualização. 

A necessidade da pessoa era poder fazer o Backup de uma tabela em qualquer momento. 

Esse código abaixo resolve esse problema:

static string ExportarDados(string tabela)

        {

            int i, j;

            string res1 = "", res2 = "";

            string queryStrutura = "select syscolumns.xtype,length,isnullable,syscolumns.name from syscolumns,sysobjects where syscolumns.id=sysobjects.id and sysobjects.name='" + tabela + "' order by colid";

            string query = "select * from " + tabela;

            DataTable dt = ObterDados(queryStrutura);

            DataTable d = ObterDados(query);

            DateTime data;

            string sql;

            for (j = 0; j < d.Rows.Count; j++)

            {

                sql = "if (select count(*) from " + tabela + " where " + dt.Rows[0][3].ToString() + "='" + d.Rows[j][0].ToString()  + "')=0 begin\r\n";

                sql += "insert " + tabela + " values(";

                for (i = 0; i < dt.Rows.Count; i++)

                {

                    switch ( dt.Rows[i][0].ToString())

                    {

                        case "35":

                        case "36":

                        case "167":

                        case "175": // campo do tipo texto

                            if (dt.Rows[i][2].ToString() == "1" && d.Rows[j][i] ==null)

                                sql += "null";

                            else

                                sql += "'" + d.Rows[j][i].ToString().Replace("'", "''") + "'";

                            break;

                        case "108": //campo do tipo numérico

                            if (dt.Rows[i][2].ToString() == "1" && d.Rows[j][i] == null)

                                sql += "null";

                            else

                                sql += d.Rows[j][i].ToString();

                            break;

                        case "61": //campo do tipo data

                            if (dt.Rows[i][2].ToString() == "1" && d.Rows[j][i] == null)

                                sql += "null";

                            else

                            {

                                data =DateTime.Parse( d.Rows[j][i].ToString());

                                sql += "convert(datetime,'" + data.Day + "/" + data.Month + "/" + data.Year + " " + data.Hour + ":" + data.Minute + ":" + data.Second + ":" + data.Millisecond + "',103)";

                            }

                            break;

                    }

                    if (i < d.Columns.Count - 1)

                        sql += ",";

                }

                sql += ")\r\nend else begin\r\n";

                sql += "update " + tabela + " set ";

                for (i = 1; i < d.Columns.Count; i++)

                {

                    sql += dt.Rows[i][3].ToString()  + "=";

                    switch (dt.Rows[i][0].ToString())

                    {

                        case "35":

                        case "36":

                        case "167":

                        case "175": // Campos do tipo texto

                            if (dt.Rows[i][2].ToString() == "1" && d.Rows[j][i] == null)

                                sql += "null";

                            else

                                sql += "'" + d.Rows[j][i].ToString().Replace("'", "''") + "'";

                            break;

                        case "108": // campos do tipo numérico

                            if (dt.Rows[i][2].ToString() == "1" && d.Rows[j][i] == null)

                                sql += "null";

                            else

                                sql += d.Rows[j][i].ToString();

                            break;

                        case "61": //campo do tipo data

                            if (dt.Rows[i][2].ToString() == "1" && d.Rows[j][i] == null)

                                sql += "null";

                            else

                            {

                                data = DateTime.Parse( d.Rows[j][i].ToString());

                                sql += "convert(datetime,'" + data.Day + "/" + data.Month + "/" + data.Year + " " + data.Hour + ":" + data.Minute + ":" + data.Second + ":" + data.Millisecond + "',103)";

                            }

                            break;

                    }

                    if (i < d.Columns.Count - 1)

                        sql += ",";

                }

                sql += " where " + dt.Rows[0][3].ToString() + "='" + d.Rows[j][0].ToString() + "'";

                sql += "\r\nend\r\nGO\r\n\r\n";

                res1 += sql;

                if ((j - 15 * (j / 15)) == 0)

                {

                    res2 += res1;

                    res1 = "";

                }

            }

            res2 += res1;

            return res2;

        }