refactor: make Junction non-recursive (#1818)
Also Cardinality now includes a Junction or ConstraintName
This commit is contained in:
Steve Chavez
@@ -33,7 +33,8 @@ import Data.Tree (Tree (..))
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import PostgREST.DbStructure.Identifiers (FieldName,
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QualifiedIdentifier (..),
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Schema, TableName)
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import PostgREST.DbStructure.Relation (Cardinality (..), Link (..),
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import PostgREST.DbStructure.Relation (Cardinality (..),
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Junction (..),
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Relation (..))
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import PostgREST.DbStructure.Table (Column (..), Table (..),
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tableQi)
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@@ -125,7 +126,7 @@ addRels :: Schema -> [Relation] -> Maybe ReadRequest -> ReadRequest -> Either Ap
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addRels schema allRels parentNode (Node (query@Select{from=tbl}, (nodeName, _, alias, hint, depth)) forest) =
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case parentNode of
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Just (Node (Select{from=parentNodeQi}, _) _) ->
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let newFrom r = if qiName tbl == nodeName then tableQi (relFTable r) else tbl
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let newFrom r = if qiName tbl == nodeName then tableQi (relForeignTable r) else tbl
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newReadNode = (\r -> (query{from=newFrom r}, (nodeName, Just r, alias, Nothing, depth))) <$> rel
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rel = findRel schema allRels (qiName parentNodeQi) nodeName hint
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in
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@@ -152,34 +153,38 @@ findRel schema allRels origin target hint =
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case rel of
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[] -> Left $ NoRelBetween origin target
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[r] -> Right r
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rs ->
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-- Return error if more than one relationship is found, unless we're in a
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-- self reference case.
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--
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-- Here we handle a self reference relationship to not cause a breaking
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-- change: In a self reference we get two relationships with the same
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-- foreign key and relTable/relFtable but with different
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-- cardinalities(m2o/o2m) We output the O2M rel, the M2O rel can be
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-- obtained by using the origin column as an embed hint.
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let [rel0, rel1] = take 2 rs in
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if length rs == 2 && relLink rel0 == relLink rel1 && relTable rel0 == relTable rel1 && relFTable rel0 == relFTable rel1
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then note (NoRelBetween origin target) (find (\r -> relType r == O2M) rs)
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else Left $ AmbiguousRelBetween origin target rs
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-- Here we handle a self reference relationship to not cause a breaking
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-- change: In a self reference we get two relationships with the same
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-- foreign key and relTable/relFtable but with different
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-- cardinalities(m2o/o2m) We output the O2M rel, the M2O rel can be
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-- obtained by using the origin column as an embed hint.
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rs@[rel0, rel1] -> case (relCardinality rel0, relCardinality rel1, relTable rel0 == relTable rel1 && relForeignTable rel0 == relForeignTable rel1) of
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(O2M cons1, M2O cons2, True) -> if cons1 == cons2 then Right rel0 else Left $ AmbiguousRelBetween origin target rs
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(M2O cons1, O2M cons2, True) -> if cons1 == cons2 then Right rel1 else Left $ AmbiguousRelBetween origin target rs
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_ -> Left $ AmbiguousRelBetween origin target rs
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rs -> Left $ AmbiguousRelBetween origin target rs
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where
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matchFKSingleCol hint_ cols = length cols == 1 && hint_ == (colName <$> head cols)
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matchConstraint tar card = case card of
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O2M cons -> tar == Just cons
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M2O cons -> tar == Just cons
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_ -> False
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matchJunction hint_ card = case card of
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M2M Junction{junTable} -> hint_ == Just (tableName junTable)
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_ -> False
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rel = filter (
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\Relation{..} ->
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-- Both relationship ends need to be on the exposed schema
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schema == tableSchema relTable && schema == tableSchema relFTable &&
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schema == tableSchema relTable && schema == tableSchema relForeignTable &&
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(
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-- /projects?select=clients(*)
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origin == tableName relTable && -- projects
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target == tableName relFTable || -- clients
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target == tableName relForeignTable || -- clients
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-- /projects?select=projects_client_id_fkey(*)
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(
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origin == tableName relTable && -- projects
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Constraint target == relLink -- projects_client_id_fkey
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origin == tableName relTable && -- projects
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matchConstraint (Just target) relCardinality -- projects_client_id_fkey
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) ||
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-- /projects?select=client_id(*)
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(
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@@ -190,20 +195,14 @@ findRel schema allRels origin target hint =
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isNothing hint || -- hint is optional
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-- /projects?select=clients!projects_client_id_fkey(*)
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(
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relType /= M2M &&
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hint == Just (constName relLink) -- projects_client_id_fkey
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) ||
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matchConstraint hint relCardinality || -- projects_client_id_fkey
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-- /projects?select=clients!client_id(*) or /projects?select=clients!id(*)
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matchFKSingleCol hint relColumns || -- client_id
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matchFKSingleCol hint relFColumns || -- id
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matchFKSingleCol hint relForeignColumns || -- id
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-- /users?select=tasks!users_tasks(*)
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(
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relType == M2M && -- many-to-many between users and tasks
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hint == Just (tableName $ junTable relLink) -- users_tasks
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)
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-- /users?select=tasks!users_tasks(*) many-to-many between users and tasks
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matchJunction hint relCardinality -- users_tasks
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)
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) allRels
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@@ -211,7 +210,7 @@ findRel schema allRels origin target hint =
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addJoinConditions :: Maybe Alias -> ReadRequest -> Either ApiRequestError ReadRequest
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addJoinConditions previousAlias (Node node@(query@Select{from=tbl}, nodeProps@(_, rel, _, _, depth)) forest) =
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case rel of
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Just r@Relation{relType=M2M, relLink=Junction{junTable}} ->
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Just r@Relation{relCardinality=M2M Junction{junTable}} ->
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let rq = augmentQuery r in
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Node (rq{implicitJoins=tableQi junTable:implicitJoins rq}, nodeProps) <$> updatedForest
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Just r -> Node (augmentQuery r, nodeProps) <$> updatedForest
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@@ -231,11 +230,11 @@ addJoinConditions previousAlias (Node node@(query@Select{from=tbl}, nodeProps@(_
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-- previousAlias and newAlias are used in the case of self joins
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getJoinConditions :: Maybe Alias -> Maybe Alias -> Relation -> [JoinCondition]
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getJoinConditions previousAlias newAlias (Relation Table{tableSchema=tSchema, tableName=tN} cols Table{tableName=ftN} fCols _ lnk) =
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case lnk of
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Junction Table{tableName=jtn} _ jc1 _ jc2 ->
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getJoinConditions previousAlias newAlias (Relation Table{tableSchema=tSchema, tableName=tN} cols Table{tableName=ftN} fCols card) =
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case card of
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M2M (Junction Table{tableName=jtn} _ jc1 _ jc2) ->
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zipWith (toJoinCondition tN jtn) cols jc1 ++ zipWith (toJoinCondition ftN jtn) fCols jc2
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Constraint _ ->
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_ ->
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zipWith (toJoinCondition tN ftN) cols fCols
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where
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toJoinCondition :: Text -> Text -> Column -> Column -> JoinCondition
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@@ -358,14 +357,10 @@ returningCols rr@(Node _ forest) pkCols
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-- be `RETURNING name`(see QueryBuilder). This would make the embedding
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-- fail because the following JOIN would need the "client_id" column from
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-- projects. So this adds the foreign key columns to ensure the embedding
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-- succeeds, result would be `RETURNING name, client_id`. This also works
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-- for the other relType's.
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-- succeeds, result would be `RETURNING name, client_id`.
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fkCols = concat $ mapMaybe (\case
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Node (_, (_, Just Relation{relColumns=cols, relType=relTyp}, _, _, _)) _ -> case relTyp of
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O2M -> Just cols
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M2O -> Just cols
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M2M -> Just cols
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_ -> Nothing
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Node (_, (_, Just Relation{relColumns=cols}, _, _, _)) _ -> Just cols
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_ -> Nothing
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) forest
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-- However if the "client_id" is present, e.g. mutateRequest to
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-- /projects?select=client_id,name,clients(name) we would get `RETURNING
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