view demo/more/versioned1.ur @ 1954:1802eb00a0ae

MySQL: catch deadlocks during queries
author Adam Chlipala <adam@chlipala.net>
date Sun, 05 Jan 2014 20:20:09 -0500
parents e6bc6bbd7a32
children
line wrap: on
line source
open Versioned.Make(struct
                        con key = [Id = int]
                        con data = [Nam = string, ShoeSize = int]

                        val key = {Id = _}
                        val data = {Nam = {Inj = _,
                                           Eq = _},
                                    ShoeSize = {Inj = _,
                                                Eq = _}}
                    end)

fun retro vr =
    ks <- keysAt vr;
    ks <- List.mapM (fn r => fso <- archive vr r; return (r.Id, fso)) ks;

    return <xml><body>
      {List.mapX (fn (k, r) => <xml><li>
        {[k]}: {case r of
                    None => <xml>Whoa!</xml>
                  | Some r => <xml>{[r.Nam]}, {[r.ShoeSize]}</xml>}
      </li></xml>) ks}
    </body></xml>

fun expandKey k =
    name <- source "";
    shoeSize <- source "";
    return {Key = k, Nam = name, ShoeSize = shoeSize}

fun main () =
    ks0 <- keys;
    ks0 <- List.mapM (fn r => expandKey r.Id) ks0;
    ks <- source ks0;

    id <- source "";
    name <- source "";
    shoeSize <- source "";

    times <- updateTimes;

    return <xml><body>
      <dyn signal={ks <- signal ks;
                   return (List.mapX (fn kr => <xml><div>
                     {[kr.Key]}:
                     <ctextbox source={kr.Nam}/>
                     <ctextbox size={5} source={kr.ShoeSize}/>
                     <button value="Latest" onclick={fn _ => ro <- rpc (current {Id = kr.Key});
                                                        case ro of
                                                            None => alert "Can't get it!"
                                                          | Some r =>
                                                            set kr.Nam r.Nam;
                                                            set kr.ShoeSize (show r.ShoeSize)}/>
                     <button value="Update" onclick={fn _ => name <- get kr.Nam;
                                                        shoeSize <- get kr.ShoeSize;
                                                        rpc (update {Id = kr.Key,
                                                                     Nam = name,
                                                                     ShoeSize = readError shoeSize})
                                                    }/>
                   </div></xml>) ks)}/>

      <h2>Add one:</h2>

      <table>
        <tr><th>Id:</th> <td><ctextbox size={5} source={id}/></td></tr>
        <tr><th>Name:</th> <td><ctextbox source={name}/></td></tr>
        <tr><th>Shoe size:</th> <td><ctextbox size={5} source={shoeSize}/></td></tr>
        <tr><th><button value="Add" onclick={fn _ => id <- get id;
                                                name <- get name;
                                                shoeSize <- get shoeSize;
                                                rpc (insert {Id = readError id, Nam = name,
                                                             ShoeSize = readError shoeSize});

                                                cur <- get ks;
                                                kr <- expandKey (readError id);
                                                set ks (kr :: cur)}/></th></tr>
      </table>

      <h2>Archive</h2>

      {List.mapX (fn (vr, tm) => <xml><li><a link={retro vr}>{[tm]}</a></li></xml>) times}
    </body></xml>