Asp.net MVC5 How can I shorten the URL of item so that It uses less space on database . I get the following error

Problem description: As an example Ebay link

Can be shortened to https://www.ebay.com/itm//263591535536, so that it takes less space on the database . I try to capture the full url in Razer page and then in the Controller I try to shorten it . Then I get the validation error . My code is:

if (ModelState.IsValid)
{
    db.Entry(home).State = EntityState.Modified;
    home.DetailUrl = RealHouses2.Models.Miscellaneous.RemoveExtraCharFromUrl(home.DetailUrl);

    db.SaveChanges();

    return RedirectToAction("Index");
}
return View(home);

Error message is:

System.Data.Entity.Validation.DbEntityValidationException HResult=0x80131920 Message=Validation failed for one or more entities. See 'EntityValidationErrors' property for more details.

Thanks, Nick.McDermaid. Yes the issue is my method to reduce the URL length does not produce the correct url. So it produce a validation error. That corrected my mistake.