Ur/Web: tests/sql_option.ur annotate

Allow subqueries to reference aggregate-only columns of free tables; treat non-COUNT aggregate functions as possibly returning NULL

author	Adam Chlipala <adam@chlipala.net>
date	Sat, 15 Jan 2011 14:53:13 -0500
parents	4efab85405be
children

rev	line source
adamc@467	1 table t : { O : option int }
adamc@467	2
adamc@467	3 fun addNull () =
adamc@467	4 dml (INSERT INTO t (O) VALUES (NULL));
adamc@467	5 return <xml>Done</xml>
adamc@467	6
adamc@468	7 fun add3 () =
adamc@468	8 dml (INSERT INTO t (O) VALUES ({Some 3}));
adamc@468	9 return <xml>Done</xml>
adamc@468	10
adamc@468	11 fun addN r =
adamc@468	12 dml (INSERT INTO t (O) VALUES ({Some (readError r.N)}));
adamc@468	13 return <xml>Done</xml>
adamc@467	14
adamc@467	15 fun main () : transaction page =
adamc@467	16 xml <- queryX (SELECT * FROM t)
adamc@467	17 (fn r => case r.T.O of
adamc@467	18 None => <xml>Nada<br/></xml>
adamc@467	19 \| Some n => <xml>Num: {[n]}<br/></xml>);
adamc@467	20 return <xml><body>
adamc@467	21 {xml}
adamc@467	22
adamc@467	23 <a link={addNull ()}>Add a null</a><br/>
adamc@468	24 <a link={add3 ()}>Add a 3</a><br/>
adamc@468	25 <form>
adamc@468	26 Add <textbox{#N}/> <submit action={addN}/>
adamc@468	27 </form>
adamc@467	28 </body></xml>

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