namespace SendMailSMSService{    class Program    {        static void Main(string[] args)        {            var connString = SqlDataHelper.GetConnectionString
     
      ();            //读取Excle文件并写入表中            var bytes = File.ReadAllBytes("a.xlsx");            var entity = new FileContent            {                FileContentID = Guid.NewGuid(),                Content = bytes            };            var count = entity.InsertToSql(connString);            //从表中读取二进制并生成Excel文件            var query = entity;            var newEntity = entity.Query(connString, _ => _.FileContentID).FirstOrDefault();            var newBytes = newEntity.Content;            var fs = File.Create("b.xlsx");            fs.Write(newBytes, 0, newBytes.Length);            fs.Flush();            fs.Close();            fs.Dispose();        }    }    [DB("FileDB")]    [Table("Portal.FileContent")]    public class FileContent    {        [Key]        [DataMapping]        [SqlDataType(System.Data.SqlDbType.UniqueIdentifier)]        public Guid FileContentID { get; set; }        [DataMapping("FileContent")]        [SqlDataType(System.Data.SqlDbType.VarBinary)]        public byte[] Content { get; set; }    }}