table tab : {Id : int, Val : int, Foo : int} PRIMARY KEY Id fun cache id = res <- oneOrNoRows (SELECT tab.Val FROM tab WHERE tab.Id = {[id]}); return Reading {[id]}. {case res of None => ? | Some row => {[row.Tab.Val]}} (* fun cache2 id v = *) (* res <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[id]} AND tab.Val = {[v]}); *) (* return *) (* Reading {[id]}. *) (* {case res of *) (* None => Nope, that's not it. *) (* | Some _ => Hooray! You guessed it!} *) (* *) (* fun cache2 id1 id2 = *) (* res1 <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[id1]}); *) (* res2 <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[id2]}); *) (* return *) (* Reading {[id1]} and {[id2]}. *) (* {case (res1, res2) of *) (* (Some _, Some _) => Both are there. *) (* | _ => One of them is missing.} *) (* *) fun flush id = dml (UPDATE tab SET Val = Val * (Id + 2) / Val - 3 WHERE Id = {[id]} OR Id = {[id - 1]} OR Id = {[id + 1]}); return Changed {[id]}! fun flash id = dml (UPDATE tab SET Foo = Val WHERE Id = {[id]} OR Id = {[id - 1]} OR Id = {[id + 1]}); return Maybe changed {[id]}? fun floosh id = dml (UPDATE tab SET Id = {[id + 1]} WHERE Id = {[id]}); return Shifted {[id]}! (* val flush17 = *) (* dml (UPDATE tab *) (* SET Val = Val * (Id + 2) / Val - 3 *) (* WHERE Id = 17); *) (* return *) (* Changed specifically 17! *) (* *) (* fun flush id = *) (* res <- oneOrNoRows (SELECT tab.Val *) (* FROM tab *) (* WHERE tab.Id = {[id]}); *) (* (case res of *) (* None => dml (INSERT INTO tab (Id, Val) *) (* VALUES ({[id]}, 0)) *) (* | Some row => dml (UPDATE tab *) (* SET Val = {[row.Tab.Val + 1]} *) (* WHERE Id = {[id]} OR Id = {[id + 1]})); *) (* return *) (* {case res of *) (* None => Initialized {[id]}! *) (* | Some row => Incremented {[id]}!} *) (* *)