how to download a file through sqlserver database using asp c#

hi,
i created database tables in sqlserver regarding upload a file its working but now i want how to down load a file through database . i was use grid view also when i upload a file it shows through gridview and if we want to delete just click delete symbol. so, any one can under stand pls send me solution.

protected void Button1_Click(object sender, EventArgs e)
    {
        if (FileUpload1.HasFile)
        {
            // delete and content with the same name
            ContentDataSource.Insert();
            // insert new content
            ContentDataSource.Delete();
            // refresh the content list
            GridView1.DataBind();
        }
    }

protected void ContentDataSource_Inserting(object sender, SqlDataSourceCommandEventArgs e)
    {
        e.Command.Parameters["@name"].Value = FileUpload1.FileName;
        e.Command.Parameters["@type"].Value = FileUpload1.PostedFile.ContentType;
        e.Command.Parameters["@length"].Value = FileUpload1.PostedFile.ContentLength;
        e.Command.Parameters["@img"].Value = FileUpload1.FileBytes;
    }
  

 protected void ContentDataSource_Deleting(object sender, SqlDataSourceCommandEventArgs e)
    {
        e.Command.Parameters["@name"].Value = FileUpload1.FileName;
        
    }