Ur/Web: demo/tree.ur annotate

Use COALESCE to hide NULL results of aggregate functions; fix bug with improper ordering of query result columns

author	Adam Chlipala <adamc@hcoop.net>
date	Thu, 25 Feb 2010 14:55:35 -0500
parents	d069b193ed6b
children

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@1078	7 con id = #Id
adamc@1078	8 con parent = #Parent
adamc@1079	9 val tab = t
adamc@469	10 end)
adamc@469	11
adamc@469	12 fun row r = <xml>
adamc@732	13 #{[r.Id]}: {[r.Nam]} <form><submit action={del r.Id} value="Delete"/></form>
adamc@471	14
adamc@471	15 <form>
adamc@471	16 Add child: <textbox{#Nam}/> <submit action={add (Some r.Id)}/>
adamc@471	17 </form>
adamc@469	18 </xml>
adamc@469	19
adamc@471	20 and main () =
adamc@469	21 xml <- tree row None;
adamc@469	22 return <xml><body>
adamc@469	23 {xml}
adamc@471	24
adamc@471	25 <form>
adamc@471	26 Add a top-level node: <textbox{#Nam}/> <submit action={add None}/>
adamc@471	27 </form>
adamc@469	28 </body></xml>
adamc@471	29
adamc@471	30 and add parent r =
adamc@471	31 id <- nextval s;
adamc@471	32 dml (INSERT INTO t (Id, Parent, Nam) VALUES ({[id]}, {[parent]}, {[r.Nam]}));
adamc@471	33 main ()
adamc@471	34
adamc@732	35 and del id () =
adamc@471	36 dml (DELETE FROM t WHERE Id = {[id]});
adamc@471	37 main ()

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