public IHttpActionResult PostPais(Pais pais)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            db.Pais.Add(pais);
            try
            {
                db.SaveChanges();
            }
            catch (DbEntityValidationException db)
            {
                foreach (var validationErrors in db.EntityValidationErrors)
                {
                    foreach (var validationError in validationErrors.ValidationErrors)
                    {
                        Trace.TraceInformation("Property: {0} Error: {1}",
                                                validationError.PropertyName,
                                                validationError.ErrorMessage);
                    }
                }
            }

            return CreatedAtRoute("DefaultApi", new { id = pais.cd_pais }, pais);
        }
        public IHttpActionResult PutPais(int id, Pais pais)
        {
            if (!ModelState.IsValid)
            {
                return BadRequest(ModelState);
            }

            if (id != pais.cd_pais)
            {
                return BadRequest();
            }

            db.Entry(pais).State = EntityState.Modified;

            try
            {
                db.SaveChanges();
            }
            catch (DbUpdateConcurrencyException)
            {
                if (!PaisExists(id))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }

            return StatusCode(HttpStatusCode.NoContent);
        }