c#链接数据库

 //数据库
    public class GF_DA
    {
        /// <summary>
        /// 执行SQL语句 sConnStr 连接字符串,sql执行的sql命令 返回第一行第一列
        /// </summary>
        /// <param name="sConnStr"></param>
        /// <param name="sql"></param>
        /// <returns></returns>
        public static object ExecSQL(string sConnStr, string sql)
        {
            using (SqlConnection conn = new SqlConnection(sConnStr))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {
                        conn.Open();
                        cmd.Connection = conn;
                        cmd.CommandText = sql;
                        return cmd.ExecuteScalar();
                    }
                    catch
                    {
                        return null;
                    }
                }

            }
        }

        /// <summary>
        /// 执行SQL数组  
        /// </summary>
        /// <param name="sConnStr"></param>
        /// <param name="alSql"></param>
        /// <param name="iLen"></param>
        public static void ExecSQL(string sConnStr, ArrayList alSql, int iLen)
        {
            using (SqlConnection conn = new SqlConnection(sConnStr))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    try
                    {
                        conn.Open();
                        cmd.Connection = conn;
                        for (int i = 0; i < alSql.Count; i++)
                        {
                            cmd.CommandText = alSql[i].ToString();
                            cmd.ExecuteNonQuery();
                            
                        }
                    }
                    catch
                    {

                    }
                }

            }
        }

        /// <summary>
        /// 填充数据 返回DataTable
        /// </summary>
        /// <param name="sConnStr"></param>
        /// <param name="sql"></param>
        /// <param name="sTableName"></param>
        /// <returns></returns>
        public static DataTable DataFill(string sConnStr, string sql, string sTableName)
        {
            using (SqlConnection conn = new SqlConnection(sConnStr))
            {
                using (SqlCommand cmd = new SqlCommand())
                {
                    DataSet ds = new DataSet();
                    try
                    {
                        conn.Open();
                        cmd.Connection = conn;
                        cmd.CommandText = sql;
                        SqlDataAdapter ap = new SqlDataAdapter(cmd);
                        ap.Fill(ds, sTableName);
                        return ds.Tables[0];
                    }
                    catch
                    {
                        return null;
                    }
                }


            }
        }
    }