Mercurial > urweb
annotate demo/refFun.ur @ 451:1bd575eb2d1e
Remove empty writes
author | Adam Chlipala <adamc@hcoop.net> |
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date | Sat, 01 Nov 2008 16:50:28 -0400 |
parents | c471345f5165 |
children | 20fab0e96217 |
rev | line source |
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adamc@419 | 1 functor Make(M : sig |
adamc@419 | 2 type data |
adamc@419 | 3 val inj : sql_injectable data |
adamc@419 | 4 end) = struct |
adamc@419 | 5 |
adamc@419 | 6 type ref = int |
adamc@419 | 7 |
adamc@419 | 8 sequence s |
adamc@419 | 9 table t : { Id : int, Data : M.data } |
adamc@419 | 10 |
adamc@419 | 11 fun new d = |
adamc@419 | 12 id <- nextval s; |
adamc@434 | 13 dml (INSERT INTO t (Id, Data) VALUES ({id}, {d})); |
adamc@419 | 14 return id |
adamc@419 | 15 |
adamc@419 | 16 fun read r = |
adamc@419 | 17 o <- oneOrNoRows (SELECT t.Data FROM t WHERE t.Id = {r}); |
adamc@419 | 18 return (case o of |
adamc@419 | 19 None => error <xml>You already deleted that ref!</xml> |
adamc@419 | 20 | Some r => r.T.Data) |
adamc@419 | 21 |
adamc@419 | 22 fun write r d = |
adamc@419 | 23 dml (UPDATE t SET Data = {d} WHERE Id = {r}) |
adamc@419 | 24 |
adamc@419 | 25 fun delete r = |
adamc@419 | 26 dml (DELETE FROM t WHERE Id = {r}) |
adamc@420 | 27 |
adamc@419 | 28 end |