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Preliminary work supporting channels in databases
author Adam Chlipala <adamc@hcoop.net>
date Thu, 26 Mar 2009 16:22:34 -0400
parents 96ebc6bdb5a0
children 1a317a707d71
rev   line source
adamc@649 1 datatype list t = Nil | Cons of t * list t
adamc@649 2
adamc@649 3 table t : {Id : int, A : string}
adamc@649 4
adamc@649 5 fun allRows () =
adamc@649 6 query (SELECT * FROM t)
adamc@649 7 (fn r acc => return (Cons ((r.T.Id, r.T.A), acc)))
adamc@649 8 Nil
adamc@649 9
adamc@649 10 fun doBatch ls =
adamc@649 11 case ls of
adamc@649 12 Nil => return ()
adamc@649 13 | Cons ((id, a), ls') =>
adamc@649 14 dml (INSERT INTO t (Id, A) VALUES ({[id]}, {[a]}));
adamc@649 15 doBatch ls'
adamc@649 16
adamc@649 17 fun del id =
adamc@649 18 dml (DELETE FROM t WHERE t.Id = {[id]})
adamc@649 19
adamc@649 20 fun show withDel lss =
adamc@649 21 let
adamc@649 22 fun show' ls =
adamc@649 23 case ls of
adamc@649 24 Nil => <xml/>
adamc@649 25 | Cons ((id, a), ls) => <xml>
adamc@649 26 <tr><td>{[id]}</td> <td>{[a]}</td> {if withDel then
adamc@649 27 <xml><td><button value="Delete" onclick={del id}/></td></xml>
adamc@649 28 else
adamc@649 29 <xml/>} </tr>
adamc@649 30 {show' ls}
adamc@649 31 </xml>
adamc@649 32 in
adamc@649 33 <xml><dyn signal={ls <- signal lss; return <xml><table>
adamc@649 34 <tr> <th>Id</th> <th>A</th> </tr>
adamc@649 35 {show' ls}
adamc@649 36 </table></xml>}/></xml>
adamc@649 37 end
adamc@649 38
adamc@649 39 fun main () =
adamc@649 40 lss <- source Nil;
adamc@649 41 batched <- source Nil;
adamc@649 42
adamc@649 43 id <- source "";
adamc@649 44 a <- source "";
adamc@649 45
adamc@649 46 let
adamc@649 47 fun add () =
adamc@649 48 id <- get id;
adamc@649 49 a <- get a;
adamc@649 50 ls <- get batched;
adamc@649 51
adamc@649 52 set batched (Cons ((readError id, a), ls))
adamc@649 53
adamc@649 54 fun exec () =
adamc@649 55 ls <- get batched;
adamc@649 56
adamc@649 57 doBatch ls;
adamc@649 58 set batched Nil
adamc@649 59 in
adamc@649 60 return <xml><body>
adamc@649 61 <h2>Rows</h2>
adamc@649 62
adamc@649 63 {show True lss}
adamc@649 64
adamc@649 65 <button value="Update" onclick={ls <- allRows (); set lss ls}/><br/>
adamc@649 66 <br/>
adamc@649 67
adamc@649 68 <h2>Batch new rows to add</h2>
adamc@649 69
adamc@649 70 <table>
adamc@649 71 <tr> <th>Id:</th> <td><ctextbox source={id}/></td> </tr>
adamc@649 72 <tr> <th>A:</th> <td><ctextbox source={a}/></td> </tr>
adamc@649 73 <tr> <th/> <td><button value="Batch it" onclick={add ()}/></td> </tr>
adamc@649 74 </table>
adamc@649 75
adamc@649 76 <h2>Already batched:</h2>
adamc@649 77 {show False batched}
adamc@649 78 <button value="Execute" onclick={exec ()}/>
adamc@649 79 </body></xml>
adamc@649 80 end