Ur/Web: demo/tree.ur annotate

Use FOREIGN KEY in Tree demo

author	Adam Chlipala <adamc@hcoop.net>
date	Thu, 09 Apr 2009 15:51:50 -0400
parents	1a317a707d71
children	5819fb63c93a

rev	line source
adamc@471	1 sequence s
adamc@469	2 table t : { Id : int, Parent : option int, Nam : string }
adamc@715	3 PRIMARY KEY Id,
adamc@715	4 CONSTRAINT F FOREIGN KEY Parent REFERENCES t (Id) ON DELETE CASCADE
adamc@469	5
adamc@469	6 open TreeFun.Make(struct
adamc@469	7 val tab = t
adamc@469	8 end)
adamc@469	9
adamc@469	10 fun row r = <xml>
adamc@471	11 #{[r.Id]}: {[r.Nam]} <a link={del r.Id}>[Delete]</a>
adamc@471	12
adamc@471	13 <form>
adamc@471	14 Add child: <textbox{#Nam}/> <submit action={add (Some r.Id)}/>
adamc@471	15 </form>
adamc@469	16 </xml>
adamc@469	17
adamc@471	18 and main () =
adamc@469	19 xml <- tree row None;
adamc@469	20 return <xml><body>
adamc@469	21 {xml}
adamc@471	22
adamc@471	23 <form>
adamc@471	24 Add a top-level node: <textbox{#Nam}/> <submit action={add None}/>
adamc@471	25 </form>
adamc@469	26 </body></xml>
adamc@471	27
adamc@471	28 and add parent r =
adamc@471	29 id <- nextval s;
adamc@471	30 dml (INSERT INTO t (Id, Parent, Nam) VALUES ({[id]}, {[parent]}, {[r.Nam]}));
adamc@471	31 main ()
adamc@471	32
adamc@471	33 and del id =
adamc@471	34 dml (DELETE FROM t WHERE Id = {[id]});
adamc@471	35 main ()

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