@app.route("/art/edit/<int:id>/", methods=["GET", "POST"])

@user_login_req def art_edit(id):    

art = Art.query.get_or_404(int(id))    

form = ArtEditForm()   

if request.method == "GET":       

form.title.data = art.title        

form.cate.data = art.cate        

form.logo.data = art.logo       

form.content.data = art.content   

if form.validate_on_submit():       

data = form.data        

art.title = data["title"]       

art.cate = data["cate"]         # 上传文件        

file = secure_filename(form.logo.data.filename)        

logo = change_name(file)        

if not os.path.exists(app.config["UP"]):           

os.makedirs(app.config["UP"])         # 保存文件      

  form.logo.data.save(app.config["UP"] + "/" + logo)       

art.logo = logo        

art.content = data["content"]        

db.session.add(art)        

db.session.commit()        

flash(u"编辑文章成功", "okey")  

  return render_template("art_edit.html", form=form, title=u"编辑文章", art=art) 

提交修改不成功，Why?