Mercurial > urweb
diff demo/constraints.ur @ 773:74a090ff296e
constraints demo
| author | Adam Chlipala <adamc@hcoop.net> |
|---|---|
| date | Sun, 03 May 2009 12:01:55 -0400 |
| parents | |
| children |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/demo/constraints.ur Sun May 03 12:01:55 2009 -0400 @@ -0,0 +1,38 @@ +table t : { Id : int, Nam : string, Parent : option int } + PRIMARY KEY Id, + CONSTRAINT Nam UNIQUE Nam, + CONSTRAINT Id CHECK Id >= 0, + CONSTRAINT Parent FOREIGN KEY Parent REFERENCES t(Id) + +fun main () = + list <- queryX (SELECT * FROM t) + (fn r => <xml><tr> + <td>{[r.T.Id]}</td> + <td>{[r.T.Nam]}</td> + <td>{case r.T.Parent of + None => <xml>NULL</xml> + | Some id => <xml>{[id]}</xml>}</td> + </tr></xml>); + return <xml><body> + <table> + <tr> <th>Id</th> <th>Name</th> <th>Parent</th> </tr> + {list} + </table> + + <form> + <table> + <tr> <th>Id:</th> <td><textbox{#Id}/></td> </tr> + <tr> <th>Name:</th> <td><textbox{#Nam}/></td> </tr> + <tr> <th>Parent:</th> <td><textbox{#Parent}/></td> </tr> + <tr> <th/> <td><submit action={add}/></td> </tr> + </table> + </form> + </body></xml> + +and add r = + dml (INSERT INTO t (Id, Nam, Parent) + VALUES ({[readError r.Id]}, {[r.Nam]}, + {[case r.Parent of + "" => None + | s => Some (readError s)]})); + main ()