How Add Update at my Haskel Yesod Project

Question

guys, i need suggestions to add Update at my Haskell Project. I'm using Yesod.

That's the part of my code that i List all the animals and for each one, a button to delete the animal. How can i make a Update, like this way ?

Thanks.

getListarAnimalR :: Handler Html
getListarAnimalR = do
             listaAnm <- runDB $ selectList [] [Asc AnimalsNome]
             defaultLayout $ [whamlet|
                 <h1> Animais cadastrados:
                 $forall Entity pid animals <- listaAnm
                     <a href=@{ChecarAnimalR pid}> #{animalsNome animals} 
                     <form method=post action=@{ChecarAnimalR pid}> 
                         <input type="submit" value="Deletar Animal"><br>
             |] >> toWidget [lucius|
                form  { display:inline; }
                input { background-color: #ecc; border:0;}
             |]


    postChecarAnimalR :: AnimalsId -> Handler Html
    postChecarAnimalR pid = do
         runDB $ delete pid
         redirect ListarAnimalR

formAnimal :: Form Animals
formAnimal = renderDivs $ Animals <$>
           areq textField "Nome: " Nothing <*>
           areq intField "Idade: " Nothing <*>
           areq (selectField racas) "Raca" Nothing