refactor: add isParent flag to O2O relationships

It allows to identify the side with the FK when isParent == False

src/PostgREST/Error.hs

@@ -369,7 +369,7 @@ compressedRel Relationship{..} =
  "cardinality" .= ("many-to-one" :: Text)
  , "relationship" .= (cons <> " using " <> qiName relTable <> fmtEls (fst <$> relColumns) <> " and " <> qiName relForeignTable <> fmtEls (snd <$> relColumns))
  ]
- O2O cons relColumns -> [
+ O2O cons relColumns _ -> [
  "cardinality" .= ("one-to-one" :: Text)
  , "relationship" .= (cons <> " using " <> qiName relTable <> fmtEls (fst <$> relColumns) <> " and " <> qiName relForeignTable <> fmtEls (snd <$> relColumns))
  ]
@@ -386,7 +386,7 @@ relHint rels = T.intercalate ", " (hintList <$> rels)
  case relCardinality of
  M2M Junction{..} -> buildHint (qiName junTable)
  M2O cons _ -> buildHint cons
- O2O cons _   -> buildHint cons
+ O2O cons _ _ -> buildHint cons
  O2M cons _ -> buildHint cons
  -- An ambiguousness error cannot happen for computed relationships TODO refactor so this mempty is not needed
  hintList ComputedRelationship{} = mempty

src/PostgREST/Plan.hs

@@ -508,7 +508,7 @@ getJoinConditions tblAlias parentAlias Relationship{relTable=qi,relForeignTable=
  toJoinCondition parentAlias tblAlias tN ftN <$> cols
  M2O _ cols ->
  toJoinCondition parentAlias tblAlias tN ftN <$> cols
- O2O _ cols ->
+ O2O _ cols _ ->
  toJoinCondition parentAlias tblAlias tN ftN <$> cols
  where
  QualifiedIdentifier{qiSchema=tSchema, qiName=tN} = qi
@@ -533,20 +533,20 @@ findRel schema allRels origin target hint =
  rs -> Left $ AmbiguousRelBetween origin target rs
  where
  matchFKSingleCol hint_ card = case card of
- O2M _ [(col, _)] -> hint_ == col
- M2O _ [(col, _)] -> hint_ == col
- O2O _ [(col, _)] -> hint_ == col
- _ -> False
+ O2M{relColumns=[(col, _)]} -> hint_ == col
+ M2O{relColumns=[(col, _)]} -> hint_ == col
+ O2O{relColumns=[(col, _)]} -> hint_ == col
+ _  -> False
  matchFKRefSingleCol hint_ card = case card of
- O2M _ [(_, fCol)] -> hint_ == fCol
- M2O _ [(_, fCol)] -> hint_ == fCol
- O2O _ [(_, fCol)] -> hint_ == fCol
- _ -> False
+ O2M{relColumns=[(_, fCol)]} -> hint_ == fCol
+ M2O{relColumns=[(_, fCol)]} -> hint_ == fCol
+ O2O{relColumns=[(_, fCol)]} -> hint_ == fCol
+ _  -> False
  matchConstraint tar card = case card of
- O2M cons _ -> tar == cons
- M2O cons _ -> tar == cons
- O2O cons _ -> tar == cons
- _ -> False
+ O2M{relCons} -> tar == relCons
+ M2O{relCons} -> tar == relCons
+ O2O{relCons} -> tar == relCons
+ _  -> False
  matchJunction hint_ card = case card of
  M2M Junction{junTable} -> hint_ == qiName junTable
  _ -> False
@@ -990,7 +990,7 @@ inferColsEmbedNeeds (Node ReadPlan{select} forest) pkCols
  Just $ fst <$> cols
  Node ReadPlan{relToParent=Just Relationship{relCardinality=M2O _ cols}} _ ->
  Just $ fst <$> cols
- Node ReadPlan{relToParent=Just Relationship{relCardinality=O2O _ cols}} _ ->
+ Node ReadPlan{relToParent=Just Relationship{relCardinality=O2O _ cols _}} _ ->
  Just $ fst <$> cols
  Node ReadPlan{relToParent=Just Relationship{relCardinality=M2M Junction{junColsSource=cols}}} _ ->
  Just $ fst <$> cols

src/PostgREST/Response/OpenAPI.hs

@@ -114,9 +114,9 @@ makeProperty tbl rels col = (colName col, Inline s)
  relsSortedByIsView = sortOn relFTableIsView [ r | r@Relationship{} <- searchedRels]
  -- Finds the relationship that has a single column foreign key
  rel = find (\case
- Relationship{relCardinality=(M2O _ relColumns)} -> [colName col] == (fst <$> relColumns)
- Relationship{relCardinality=(O2O _ relColumns)} -> [colName col] == (fst <$> relColumns)
- _ -> False
+ Relationship{relCardinality=(M2O _ relColumns)}  -> [colName col] == (fst <$> relColumns)
+ Relationship{relCardinality=(O2O _ relColumns False)} -> [colName col] == (fst <$> relColumns)
+ _  -> False
  ) relsSortedByIsView
  fCol = (headMay . (\r -> snd <$> relColumns (relCardinality r)) =<< rel)
  fTbl = qiName . relForeignTable <$> rel

src/PostgREST/SchemaCache.hs

@@ -252,7 +252,7 @@ decodeRels :: HD.Result [Relationship]
 decodeRels =
  HD.rowList relRow
  where
- relRow = (\(qi1, qi2, isSelf, constr, cols, isOneToOne) -> Relationship qi1 qi2 isSelf ((if isOneToOne then O2O else M2O) constr cols) False False) <$> row
+ relRow = (\(qi1, qi2, isSelf, constr, cols, isOneToOne)-> Relationship qi1 qi2 isSelf (if isOneToOne then O2O constr cols False else M2O constr cols) False False) <$> row
  row =
  (,,,,,) <$>
  (QualifiedIdentifier <$> column HD.text <*> column HD.text) <*>
@@ -518,21 +518,22 @@ addViewM2OAndO2ORels :: [ViewKeyDependency] -> [Relationship] -> [Relationship]
 addViewM2OAndO2ORels keyDeps rels =
  rels ++ concatMap viewRels rels
  where
- isM2O card = case card of {M2O _ _ -> True; _ -> False;}
- isO2O card = case card of {O2O _ _ -> True; _ -> False;}
+ isM2O card = case card of {M2O _ _  -> True; _ -> False;}
+ isO2O card = case card of {O2O _ _ False -> True; _ -> False;}
  viewRels Relationship{relTable,relForeignTable,relCardinality=card} =
  if isM2O card || isO2O card then
  let
  cons = relCons card
  relCols = relColumns card
+ buildCard cns cls = if isM2O card then M2O cns cls else O2O cns cls False
  viewTableRels = filter (\ViewKeyDependency{keyDepTable, keyDepCons, keyDepType} -> keyDepTable == relTable && keyDepCons == cons && keyDepType == FKDep) keyDeps
  tableViewRels = filter (\ViewKeyDependency{keyDepTable, keyDepCons, keyDepType} -> keyDepTable == relForeignTable && keyDepCons == cons && keyDepType == FKDepRef) keyDeps
  in
  [ Relationship
  (keyDepView vwTbl)
  relForeignTable
  False
- ((if isM2O card then M2O else O2O) cons $ zipWith (\(_, vCol) (_, fCol)-> (vCol, fCol)) keyDepColsVwTbl relCols)
+ (buildCard cons $ zipWith (\(_, vCol) (_, fCol)-> (vCol, fCol)) keyDepColsVwTbl relCols)
  True
  False
  | vwTbl <- viewTableRels
@@ -542,7 +543,7 @@ addViewM2OAndO2ORels keyDeps rels =
  relTable
  (keyDepView tblVw)
  False
- ((if isM2O card then M2O else O2O) cons $ zipWith (\(tCol, _) (_, vCol) -> (tCol, vCol)) relCols keyDepColsTblVw)
+ (buildCard cons $ zipWith (\(tCol, _) (_, vCol) -> (tCol, vCol)) relCols keyDepColsTblVw)
  False
  True
  | tblVw <- tableViewRels
@@ -557,7 +558,7 @@ addViewM2OAndO2ORels keyDeps rels =
  vw1
  vw2
  (vw1 == vw2)
- ((if isM2O card then M2O else O2O) cons $ zipWith (\(_, vcol1) (_, vcol2) -> (vcol1, vcol2)) keyDepColsVwTbl keyDepColsTblVw)
+ (buildCard cons $ zipWith (\(_, vcol1) (_, vcol2) -> (vcol1, vcol2)) keyDepColsVwTbl keyDepColsTblVw)
  True
  True
  | vwTbl <- viewTableRels
@@ -572,7 +573,7 @@ addInverseRels :: [Relationship] -> [Relationship]
 addInverseRels rels =
  rels ++
  [ Relationship ft t isSelf (O2M cons (swap <$> cols)) fTableIsView tableIsView | Relationship t ft isSelf (M2O cons cols) tableIsView fTableIsView <- rels ] ++
- [ Relationship ft t isSelf (O2O cons (swap <$> cols)) fTableIsView tableIsView | Relationship t ft isSelf (O2O cons cols) tableIsView fTableIsView <- rels ]
+ [ Relationship ft t isSelf (O2O cons (swap <$> cols) (not isParent)) fTableIsView tableIsView | Relationship t ft isSelf (O2O cons cols isParent) tableIsView fTableIsView <- rels ]
 
 -- | Adds a m2m relationship if a table has FKs to two other tables and the FK columns are part of the PK columns
 addM2MRels :: TablesMap -> [Relationship] -> [Relationship]

src/PostgREST/SchemaCache/Relationship.hs

@@ -44,8 +44,8 @@ data Cardinality
  -- ^ one-to-many
  | M2O {relCons :: FKConstraint, relColumns :: [(FieldName, FieldName)]}
  -- ^ many-to-one
- | O2O {relCons :: FKConstraint, relColumns :: [(FieldName, FieldName)]}
- -- ^ one-to-one, this is a refinement over M2O so operating on it is pretty much the same as M2O
+ | O2O {relCons :: FKConstraint, relColumns :: [(FieldName, FieldName)], isParent :: Bool}
+ -- ^ one-to-one, this is a refinement over M2O, operating on it is pretty much the same as M2O when isParent == False
  | M2M Junction
  -- ^ many-to-many
  deriving (Eq, Show, Ord, Generic, JSON.ToJSON)
@@ -67,7 +67,7 @@ type RelationshipsMap = HM.HashMap (QualifiedIdentifier, Schema) [Relationship]
 
 relIsToOne :: Relationship -> Bool
 relIsToOne rel = case rel of
- Relationship{relCardinality=M2O _ _} -> True
- Relationship{relCardinality=O2O _ _} -> True
- ComputedRelationship{relToOne=True}  -> True
- _  -> False
+ Relationship{relCardinality=M2O {}} -> True
+ Relationship{relCardinality=O2O {}} -> True
+ ComputedRelationship{relToOne=True} -> True
+ _ -> False