adding default and FromField instance for interval.

IHP/IDE/SchemaDesigner/Compiler.hs

@@ -184,7 +184,8 @@ compilePostgresType PPolygon = "POLYGON"
 compilePostgresType PDate = "DATE"
 compilePostgresType PBinary = "BYTEA"
 compilePostgresType PTime = "TIME"
-compilePostgresType PInterval = "INTERVAL"
+compilePostgresType (PInterval Nothing) = "INTERVAL"
+compilePostgresType (PInterval (Just fields)) = "INTERVAL" <> " " <> fields
 compilePostgresType (PNumeric (Just precision) (Just scale)) = "NUMERIC(" <> show precision <> "," <> show scale <> ")"
 compilePostgresType (PNumeric (Just precision) Nothing) = "NUMERIC(" <> show precision <> ")"
 compilePostgresType (PNumeric Nothing _) = "NUMERIC"

IHP/IDE/SchemaDesigner/Parser.hs

@@ -350,9 +350,9 @@ sqlType = choice $ map optionalArray
 
                 interval = do
                     try (symbol' "INTERVAL")
-                    optional do
-                          choice $ map symbol' intervalFields
-                    pure PInterval
+                    fields <- optional do
+                        choice $ map symbol' intervalFields
+                    pure (PInterval fields)
 
                 numericPS = do
                     try (symbol' "NUMERIC(")

IHP/IDE/SchemaDesigner/Types.hs

@@ -211,7 +211,7 @@ data PostgresType
     | PDate
     | PBinary
     | PTime
-    | PInterval
+    | PInterval {fields :: Maybe Text}
     | PNumeric { precision :: Maybe Int, scale :: Maybe Int }
     | PVaryingN (Maybe Int)
     | PCharacterN Int

IHP/ModelSupport.hs

@@ -664,6 +664,9 @@ type family Include' (name :: [GHC.Types.Symbol]) model where
     Include' '[] model = model
     Include' (x:xs) model = Include' xs (Include x model)
 
+instance Default NominalDiffTime where
+    def = 0
+
 instance Default TimeOfDay where
     def = TimeOfDay 0 0 0
 
@@ -883,6 +886,47 @@ instance Exception EnhancedSqlError
 instance Default Aeson.Value where
     def = Aeson.Null
 
+-- | See https://stackoverflow.com/questions/32398878/converting-postgres-interval-to-haskell-nominaltimediff-with-postgresql-simple
+-- To support NominalDiffTime we parse Y year[s] M mon[s] D day[s] [-]HHH:MM:SS.[SSSs]
+-- The default is the postgres format.
+-- Corresponds to the postgresql interval 6 months see the documentation (https://www.postgresql.org/docs/current/datatype-datetime.html).
+instance FromField NominalDiffTime where
+    fromField f mdat =
+        if typeOid f /= typoid interval
+            then returnError Incompatible f ""
+            else case mdat of
+                Nothing  -> returnError UnexpectedNull f ""
+                Just dat -> case parseOnly (pNominalDiffTime <* endOfInput) dat of
+                    Left msg  -> returnError ConversionFailed f msg
+                    Right t   -> return t
+
+pNominalDiffTime :: Parser NominalDiffTime
+pNominalDiffTime = do
+    (years, mons, days) <- pCalTime
+    (h, m, s) <- pClockTime
+
+    let calTime =  fromRational . toRational $ (\[y,m,d] -> (365*nominalDay*y 30*nominalDay*m + nominalDay*d) $ map (fromMaybe 0) [years, mons, days]
+    let clockTime = fromRational . toRational $ s + 60*(fromIntegral m) + 60*60*(fromIntegral h)
+
+    pure (calTime + clockTime)
+
+-- | Parse a limited postgres interval of the form [-]HHH:MM:SS.[SSSS] (no larger units than hours).
+pCalTime :: Parser (Maybe Int, Maybe Int, Maybe Int)
+pCalTime = do
+    years <- try $ signed decimal <* choice $ map symbol' ["years", "year"]
+    mons  <-  try $ signed decimal <* choice $ map symbol' ["mons", "mon"]
+    days <-  try $ signed decimal <* choice $ map symbol' ["days", "day"]
+    pure (years, mons, days)
+
+-- | Parse a limited postgres interval of the form [-]HHH:MM:SS.[SSSS] (no larger units than hours).
+pClockTime :: Parser (Int, Int, Pico)
+pClockTime = do
+    h <- try $ signed decimal <* char ':'
+    m <- try $ twoDigits <* char ':'
+    s <- try seconds
+    if m < 60 && s <= 60
+        then return (h, m, s)
+        else fail "invalid interval"
 
 -- | This instancs allows us to avoid wrapping lists with PGArray when
 -- using sql types such as @INT[]@

IHP/SchemaCompiler.hs

@@ -68,6 +68,7 @@ atomicType = \case
     PDate -> "Data.Time.Calendar.Day"
     PBinary -> "(Binary ByteString)"
     PTime -> "TimeOfDay"
+    (PInterval _) -> "NominalDiffTime"
     PCustomType theType -> tableNameToModelName theType
     PTimestamp -> "LocalTime"
     (PNumeric _ _) -> "Scientific"