Time MIN/MAX

2 files changed, 18 insertions, 0 deletions

diff --git a/lib/top.ur b/lib/top.ur
index 0bc345de..d36af3f3 100644
--- a/lib/top.ur
+++ b/lib/top.ur
@@ -157,3 +157,11 @@ fun oneOrNoRows (tables ::: {{Type}}) (exps ::: {Type})
     query q
           (fn fs _ => return (Some fs))
           None
+
+fun oneRow (tables ::: {{Type}}) (exps ::: {Type})
+                (q : sql_query tables exps) [tables ~ exps] =
+    o <- oneOrNoRows q;
+    return (case o of
+                None => error <xml>Query returned no rows</xml>
+              | Some r => r)
+
diff --git a/lib/top.urs b/lib/top.urs
index 22cebb16..6e9dda4e 100644
--- a/lib/top.urs
+++ b/lib/top.urs
@@ -116,3 +116,13 @@ val oneOrNoRows : tables ::: {{Type}} -> exps ::: {Type}
                                                       [[nm] ~ acc] =>
                                                    [nm = $fields] ++ acc)
                                                    [] tables))
+
+val oneRow : tables ::: {{Type}} -> exps ::: {Type}
+             -> sql_query tables exps
+             -> fn [tables ~ exps] =>
+                   transaction
+                       $(exps
+                             ++ fold (fn nm (fields :: {Type}) acc
+                                            [[nm] ~ acc] =>
+                                         [nm = $fields] ++ acc)
+                                         [] tables)