esqueleto-3.4.2.0: src/Database/Esqueleto/Experimental.hs
{-# LANGUAGE CPP #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE FunctionalDependencies #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE PatternSynonyms #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
-- | This module contains a new way (introduced in 3.3.3.0) of using @FROM@ in
-- Haskell. The old method was a bit finicky and could permit runtime errors,
-- and this new way is both significantly safer and much more powerful.
--
-- Esqueleto users are encouraged to migrate to this module, as it will become
-- the default in a new major version @4.0.0.0@.
module Database.Esqueleto.Experimental
( -- * Setup
-- $setup
-- * Introduction
-- $introduction
-- * A New Syntax
-- $new-syntax
-- * Documentation
From(..)
, on
, from
, (:&)(..)
-- ** Set Operations
-- $sql-set-operations
, union_
, Union(..)
, unionAll_
, UnionAll(..)
, except_
, Except(..)
, intersect_
, Intersect(..)
, pattern SelectQuery
-- ** Common Table Expressions
, with
, withRecursive
-- * Internals
, ToFrom(..)
, ToMaybe(..)
, ToAlias(..)
, ToAliasT
, ToAliasReference(..)
, ToAliasReferenceT
, ValidOnClauseValue
-- * The Normal Stuff
, where_
, groupBy
, orderBy
, rand
, asc
, desc
, limit
, offset
, distinct
, distinctOn
, don
, distinctOnOrderBy
, having
, locking
, sub_select
, (^.)
, (?.)
, val
, isNothing
, just
, nothing
, joinV
, withNonNull
, countRows
, count
, countDistinct
, not_
, (==.)
, (>=.)
, (>.)
, (<=.)
, (<.)
, (!=.)
, (&&.)
, (||.)
, between
, (+.)
, (-.)
, (/.)
, (*.)
, random_
, round_
, ceiling_
, floor_
, min_
, max_
, sum_
, avg_
, castNum
, castNumM
, coalesce
, coalesceDefault
, lower_
, upper_
, trim_
, ltrim_
, rtrim_
, length_
, left_
, right_
, like
, ilike
, (%)
, concat_
, (++.)
, castString
, subList_select
, valList
, justList
, in_
, notIn
, exists
, notExists
, set
, (=.)
, (+=.)
, (-=.)
, (*=.)
, (/=.)
, case_
, toBaseId
, subSelect
, subSelectMaybe
, subSelectCount
, subSelectForeign
, subSelectList
, subSelectUnsafe
, ToBaseId(..)
, when_
, then_
, else_
, Value(..)
, ValueList(..)
, OrderBy
, DistinctOn
, LockingKind(..)
, SqlString
-- ** Joins
, InnerJoin(..)
, CrossJoin(..)
, LeftOuterJoin(..)
, RightOuterJoin(..)
, FullOuterJoin(..)
, JoinKind(..)
, OnClauseWithoutMatchingJoinException(..)
-- * SQL backend
, SqlQuery
, SqlExpr
, SqlEntity
, select
, selectSource
, delete
, deleteCount
, update
, updateCount
, insertSelect
, insertSelectCount
, (<#)
, (<&>)
-- ** Rendering Queries
, renderQueryToText
, renderQuerySelect
, renderQueryUpdate
, renderQueryDelete
, renderQueryInsertInto
-- * Internal.Language
-- * RDBMS-specific modules
-- $rdbmsSpecificModules
-- * Helpers
, valkey
, valJ
, associateJoin
-- * Re-exports
-- $reexports
, deleteKey
, module Database.Esqueleto.Internal.PersistentImport
) where
import Control.Monad.Trans.Class (lift)
import qualified Control.Monad.Trans.State as S
import qualified Control.Monad.Trans.Writer as W
#if __GLASGOW_HASKELL__ < 804
import Data.Semigroup
#endif
import Data.Kind (Constraint)
import Data.Proxy (Proxy(..))
import qualified Data.Text.Lazy.Builder as TLB
import Database.Esqueleto.Internal.Internal hiding (From, from, on)
import Database.Esqueleto.Internal.PersistentImport
import GHC.TypeLits
import Database.Persist (EntityNameDB(..))
-- $setup
--
-- If you're already using "Database.Esqueleto", then you can get
-- started using this module just by changing your imports slightly,
-- as well as enabling the [TypeApplications](https://downloads.haskell.org/~ghc/latest/docs/html/users_guide/glasgow_exts.html#extension-TypeApplications) extension.
--
-- @
-- {-\# LANGUAGE TypeApplications \#-}
--
-- ...
--
-- import Database.Esqueleto.Experimental
-- @
--
-- Note: Prior to @esqueleto-3.3.4.0@, the @Database.Esqueleto.Experimental@
-- module did not reexport @Data.Esqueleto@.
----------------------------------------------------------------------
-- $introduction
--
-- This module is fully backwards-compatible extension to the @esqueleto@
-- EDSL that expands subquery functionality and enables
-- [SQL set operations](https://en.wikipedia.org/wiki/Set_operations_(SQL\))
-- to be written directly in Haskell. Specifically, this enables:
--
-- * Subqueries in 'JOIN' statements
-- * 'UNION'
-- * 'UNION' 'ALL'
-- * 'INTERSECT'
-- * 'EXCEPT'
--
-- As a consequence of this, several classes of runtime errors are now
-- caught at compile time. This includes missing 'on' clauses and improper
-- handling of @Maybe@ values in outer joins.
--
-- This module can be used in conjunction with the main "Database.Esqueleto"
-- module, but doing so requires qualified imports to avoid ambiguous
-- definitions of 'on' and 'from', which are defined in both modules.
--
-- Below we will give an overview of how to use this module and the
-- features it enables.
----------------------------------------------------------------------
-- $new-syntax
--
-- This module introduces a new syntax that serves to enable the aforementioned
-- features. This new syntax also changes how joins written in the @esqueleto@
-- EDSL to more closely resemble the underlying SQL.
--
-- For our examples, we'll use a schema similar to the one in the Getting Started
-- section of "Database.Esqueleto":
--
-- @
-- share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persist|
-- Person
-- name String
-- age Int Maybe
-- deriving Eq Show
-- BlogPost
-- title String
-- authorId PersonId
-- deriving Eq Show
-- Follow
-- follower PersonId
-- followed PersonId
-- deriving Eq Show
-- |]
-- @
--
-- === Example 1: Simple select
--
-- Let's select all people who are named \"John\".
--
-- ==== "Database.Esqueleto":
--
-- @
-- select $
-- from $ \\people -> do
-- where_ (people ^. PersonName ==. val \"John\")
-- pure people
-- @
--
-- ==== "Database.Esqueleto.Experimental":
--
-- @
-- select $ do
-- people <- from $ Table \@Person
-- where_ (people ^. PersonName ==. val \"John\")
-- pure people
-- @
--
--
-- === Example 2: Select with join
--
-- Let's select all people and their blog posts who are over
-- the age of 18.
--
-- ==== "Database.Esqueleto":
--
-- @
-- select $
-- from $ \\(people \`LeftOuterJoin\` blogPosts) -> do
-- on (people ^. PersonId ==. blogPosts ?. BlogPostAuthorId)
-- where_ (people ^. PersonAge >. val 18)
-- pure (people, blogPosts)
-- @
--
-- ==== "Database.Esqueleto.Experimental":
--
-- Here we use the ':&' operator to pattern match against the joined tables.
--
-- @
-- select $ do
-- (people :& blogPosts) <-
-- from $ Table \@Person
-- \`LeftOuterJoin\` Table \@BlogPost
-- \`on\` (\\(people :& blogPosts) ->
-- people ^. PersonId ==. blogPosts ?. BlogPostAuthorId)
-- where_ (people ^. PersonAge >. val 18)
-- pure (people, blogPosts)
-- @
--
-- === Example 3: Select with multi-table join
--
-- Let's select all people who follow a person named \"John\", including
-- the name of each follower.
--
-- ==== "Database.Esqueleto":
--
-- @
-- select $
-- from $ \\(
-- people1
-- \`InnerJoin\` followers
-- \`InnerJoin\` people2
-- ) -> do
-- on (people1 ^. PersonId ==. followers ^. FollowFollowed)
-- on (followers ^. FollowFollower ==. people2 ^. PersonId)
-- where_ (people1 ^. PersonName ==. val \"John\")
-- pure (followers, people2)
-- @
--
-- ==== "Database.Esqueleto.Experimental":
--
-- In this version, with each successive 'on' clause, only the tables
-- we have already joined into are in scope, so we must pattern match
-- accordingly. In this case, in the second 'InnerJoin', we do not use
-- the first `Person` reference, so we use @_@ as a placeholder to
-- ignore it. This prevents a possible runtime error where a table
-- is referenced before it appears in the sequence of 'JOIN's.
--
-- @
-- select $ do
-- (people1 :& followers :& people2) <-
-- from $ Table \@Person
-- \`InnerJoin` Table \@Follow
-- \`on\` (\\(people1 :& followers) ->
-- people1 ^. PersonId ==. followers ^. FollowFollowed)
-- \`InnerJoin` Table \@Person
-- \`on\` (\\(_ :& followers :& people2) ->
-- followers ^. FollowFollower ==. people2 ^. PersonId)
-- where_ (people1 ^. PersonName ==. val \"John\")
-- pure (followers, people2)
-- @
--
-- === Example 4: Counting results of a subquery
--
-- Let's count the number of people who have posted at least 10 posts
--
-- ==== "Database.Esqueleto":
--
-- @
-- select $ pure $ subSelectCount $
-- from $ \\(
-- people
-- \`InnerJoin\` blogPosts
-- ) -> do
-- on (people ^. PersonId ==. blogPosts ^. BlogPostAuthorId)
-- groupBy (people ^. PersonId)
-- having ((count $ blogPosts ^. BlogPostId) >. val 10)
-- pure people
-- @
--
-- ==== "Database.Esqueleto.Experimental":
--
-- @
-- select $ do
-- peopleWithPosts <-
-- from $ do
-- (people :& blogPosts) <-
-- from $ Table \@Person
-- \`InnerJoin\` Table \@BlogPost
-- \`on\` (\\(p :& bP) ->
-- p ^. PersonId ==. bP ^. BlogPostAuthorId)
-- groupBy (people ^. PersonId)
-- having ((count $ blogPosts ^. BlogPostId) >. val 10)
-- pure people
-- pure $ count (peopleWithPosts ^. PersonId)
-- @
--
-- We now have the ability to refactor this
--
-- === Example 5: Sorting the results of a UNION with limits
--
-- Out of all of the posts created by a person and the people they follow,
-- generate a list of the first 25 posts, sorted alphabetically.
--
-- ==== "Database.Esqueleto":
--
-- Since 'UNION' is not supported, this requires using `Database.Esqueleto.rawSql`. (Not shown)
--
-- ==== "Database.Esqueleto.Experimental":
--
-- Since this module supports all set operations (see `SqlSetOperation`), we can use
-- `Union` to write this query.
--
-- @
-- select $ do
-- (authors, blogPosts) <- from $
-- (do
-- (author :& blogPost) <-
-- from $ Table \@Person
-- \`InnerJoin\` Table \@BlogPost
-- \`on\` (\\(a :& bP) ->
-- a ^. PersonId ==. bP ^. BlogPostAuthorId)
-- where_ (author ^. PersonId ==. val currentPersonId)
-- pure (author, blogPost)
-- )
-- \`union_\`
-- (do
-- (follow :& blogPost :& author) <-
-- from $ Table \@Follow
-- \`InnerJoin\` Table \@BlogPost
-- \`on\` (\\(f :& bP) ->
-- f ^. FollowFollowed ==. bP ^. BlogPostAuthorId)
-- \`InnerJoin\` Table \@Person
-- \`on\` (\\(_ :& bP :& a) ->
-- bP ^. BlogPostAuthorId ==. a ^. PersonId)
-- where_ (follow ^. FollowFollower ==. val currentPersonId)
-- pure (author, blogPost)
-- )
-- orderBy [ asc (blogPosts ^. BlogPostTitle) ]
-- limit 25
-- pure (authors, blogPosts)
-- @
--
-- === Example 6: LATERAL JOIN
--
-- As of version @3.4.0.0@, lateral subquery joins are supported.
--
--
-- @
-- select $ do
-- (salesPerson :& maxSaleAmount :& maxSaleCustomerName) <-
-- from $ Table \@SalesPerson
-- \`CrossJoin\` (\\salesPerson -> do
-- sales <- from $ Table \@Sale
-- where_ $ sales ^. SaleSalesPersonId ==. salesPerson ^. SalesPersonId
-- pure $ max_ (sales ^. SaleAmount)
-- )
-- \`CrossJoin\` (\\(salesPerson :& maxSaleAmount) -> do
-- sales <- from $ Table \@Sale
-- where_ $ sales ^. SaleSalesPersonId ==. salesPerson ^. SalesPersonId
-- &&. sales ^. SaleAmount ==. maxSaleAmount
-- pure $ sales ^. SaleCustomerName)
-- )
-- pure (salesPerson ^. SalesPersonName, maxSaleAmount, maxSaleCustomerName)
-- @
--
-- This is the equivalent to the following SQL (example taken from the
-- [MySQL Lateral Derived Table](https://dev.mysql.com/doc/refman/8.0/en/lateral-derived-tables.html)
-- documentation):
--
-- @
-- SELECT
-- salesperson.name,
-- max_sale.amount,
-- max_sale_customer.customer_name
-- FROM
-- salesperson,
-- -- calculate maximum size, cache it in transient derived table max_sale
-- LATERAL
-- (SELECT MAX(amount) AS amount
-- FROM all_sales
-- WHERE all_sales.salesperson_id = salesperson.id)
-- AS max_sale,
-- LATERAL
-- (SELECT customer_name
-- FROM all_sales
-- WHERE all_sales.salesperson_id = salesperson.id
-- AND all_sales.amount =
-- -- the cached maximum size
-- max_sale.amount)
-- AS max_sale_customer;
-- @
-- | A left-precedence pair. Pronounced \"and\". Used to represent expressions
-- that have been joined together.
--
-- The precedence behavior can be demonstrated by:
--
-- @
-- a :& b :& c == ((a :& b) :& c)
-- @
--
-- See the examples at the beginning of this module to see how this
-- operator is used in 'JOIN' operations.
data (:&) a b = a :& b
infixl 2 :&
data SqlSetOperation a
= SqlSetUnion (SqlSetOperation a) (SqlSetOperation a)
| SqlSetUnionAll (SqlSetOperation a) (SqlSetOperation a)
| SqlSetExcept (SqlSetOperation a) (SqlSetOperation a)
| SqlSetIntersect (SqlSetOperation a) (SqlSetOperation a)
| SelectQueryP NeedParens (SqlQuery a)
-- $sql-set-operations
--
-- Data type that represents SQL set operations. This includes
-- 'UNION', 'UNION' 'ALL', 'EXCEPT', and 'INTERSECT'. These types form
-- a binary tree, with @SqlQuery@ values on the leaves.
--
-- Each function corresponding to the aforementioned set operations
-- can be used as an infix in a @from@ to help with readability
-- and lead to code that closely resembles the underlying SQL. For example,
--
-- @
-- select $ from $
-- (do
-- a <- from Table @A
-- pure $ a ^. ASomeCol
-- )
-- \`union_\`
-- (do
-- b <- from Table @B
-- pure $ b ^. BSomeCol
-- )
-- @
--
-- is translated into
--
-- @
-- SELECT * FROM (
-- (SELECT a.some_col FROM a)
-- UNION
-- (SELECT b.some_col FROM b)
-- )
-- @
--
{-# DEPRECATED Union "/Since: 3.4.0.0/ - Use the 'union_' function instead of the 'Union' data constructor" #-}
data Union a b = a `Union` b
-- | @UNION@ SQL set operation. Can be used as an infix function between 'SqlQuery' values.
union_ :: a -> b -> Union a b
union_ = Union
{-# DEPRECATED UnionAll "/Since: 3.4.0.0/ - Use the 'unionAll_' function instead of the 'UnionAll' data constructor" #-}
data UnionAll a b = a `UnionAll` b
-- | @UNION@ @ALL@ SQL set operation. Can be used as an infix function between 'SqlQuery' values.
unionAll_ :: a -> b -> UnionAll a b
unionAll_ = UnionAll
{-# DEPRECATED Except "/Since: 3.4.0.0/ - Use the 'except_' function instead of the 'Except' data constructor" #-}
data Except a b = a `Except` b
-- | @EXCEPT@ SQL set operation. Can be used as an infix function between 'SqlQuery' values.
except_ :: a -> b -> Except a b
except_ = Except
{-# DEPRECATED Intersect "/Since: 3.4.0.0/ - Use the 'intersect_' function instead of the 'Intersect' data constructor" #-}
data Intersect a b = a `Intersect` b
-- | @INTERSECT@ SQL set operation. Can be used as an infix function between 'SqlQuery' values.
intersect_ :: a -> b -> Intersect a b
intersect_ = Intersect
class SetOperationT a ~ b => ToSetOperation a b | a -> b where
type SetOperationT a
toSetOperation :: a -> SqlSetOperation b
instance ToSetOperation (SqlSetOperation a) a where
type SetOperationT (SqlSetOperation a) = a
toSetOperation = id
instance ToSetOperation (SqlQuery a) a where
type SetOperationT (SqlQuery a) = a
toSetOperation = SelectQueryP Never
instance (ToSetOperation a c, ToSetOperation b c) => ToSetOperation (Union a b) c where
type SetOperationT (Union a b) = SetOperationT a
toSetOperation (Union a b) = SqlSetUnion (toSetOperation a) (toSetOperation b)
instance (ToSetOperation a c, ToSetOperation b c) => ToSetOperation (UnionAll a b) c where
type SetOperationT (UnionAll a b) = SetOperationT a
toSetOperation (UnionAll a b) = SqlSetUnionAll (toSetOperation a) (toSetOperation b)
instance (ToSetOperation a c, ToSetOperation b c) => ToSetOperation (Except a b) c where
type SetOperationT (Except a b) = SetOperationT a
toSetOperation (Except a b) = SqlSetExcept (toSetOperation a) (toSetOperation b)
instance (ToSetOperation a c, ToSetOperation b c) => ToSetOperation (Intersect a b) c where
type SetOperationT (Intersect a b) = SetOperationT a
toSetOperation (Intersect a b) = SqlSetIntersect (toSetOperation a) (toSetOperation b)
{-# DEPRECATED SelectQuery "/Since: 3.4.0.0/ - It is no longer necessary to tag 'SqlQuery' values with @SelectQuery@" #-}
pattern SelectQuery :: SqlQuery a -> SqlSetOperation a
pattern SelectQuery q = SelectQueryP Never q
-- | Data type that represents the syntax of a 'JOIN' tree. In practice,
-- only the @Table@ constructor is used directly when writing queries. For example,
--
-- @
-- select $ from $ Table \@People
-- @
data From a where
Table
:: PersistEntity ent
=> From (SqlExpr (Entity ent))
SubQuery
:: ( SqlSelect a r
, ToAlias a
, ToAliasReference a
)
=> SqlQuery a
-> From a
FromCte
:: Ident
-> a
-> From a
SqlSetOperation
:: ( SqlSelect a r
, ToAlias a
, ToAliasReference a
)
=> SqlSetOperation a
-> From a
InnerJoinFrom
:: From a
-> (From b, (a :& b) -> SqlExpr (Value Bool))
-> From (a :& b)
InnerJoinFromLateral
:: ( SqlSelect b r
, ToAlias b
, ToAliasReference b
)
=> From a
-> ((a -> SqlQuery b), (a :& b) -> SqlExpr (Value Bool))
-> From (a :& b)
CrossJoinFrom
:: From a
-> From b
-> From (a :& b)
CrossJoinFromLateral
:: ( SqlSelect b r
, ToAlias b
, ToAliasReference b
)
=> From a
-> (a -> SqlQuery b)
-> From (a :& b)
LeftJoinFrom
:: ToMaybe b
=> From a
-> (From b, (a :& ToMaybeT b) -> SqlExpr (Value Bool))
-> From (a :& ToMaybeT b)
LeftJoinFromLateral
:: ( SqlSelect b r
, ToAlias b
, ToAliasReference b
, ToMaybe b
)
=> From a
-> ((a -> SqlQuery b), (a :& ToMaybeT b) -> SqlExpr (Value Bool))
-> From (a :& ToMaybeT b)
RightJoinFrom
:: ToMaybe a
=> From a
-> (From b, (ToMaybeT a :& b) -> SqlExpr (Value Bool))
-> From (ToMaybeT a :& b)
FullJoinFrom
:: (ToMaybe a, ToMaybe b )
=> From a
-> (From b, (ToMaybeT a :& ToMaybeT b) -> SqlExpr (Value Bool))
-> From (ToMaybeT a :& ToMaybeT b)
-- | Constraint for `on`. Ensures that only types that require an `on` can be used on
-- the left hand side. This was previously reusing the ToFrom class which was actually
-- a bit too lenient as it allowed to much.
--
-- @since 3.4.0.0
type family ValidOnClauseValue a :: Constraint where
ValidOnClauseValue (From a) = ()
ValidOnClauseValue (SqlQuery a) = ()
ValidOnClauseValue (SqlSetOperation a) = ()
ValidOnClauseValue (a -> SqlQuery b) = ()
ValidOnClauseValue _ = TypeError ('Text "Illegal use of ON")
-- | An @ON@ clause that describes how two tables are related. This should be
-- used as an infix operator after a 'JOIN'. For example,
--
-- @
-- select $
-- from $ Table \@Person
-- \`InnerJoin\` Table \@BlogPost
-- \`on\` (\\(p :& bP) ->
-- p ^. PersonId ==. bP ^. BlogPostAuthorId)
-- @
on :: ValidOnClauseValue a => a -> (b -> SqlExpr (Value Bool)) -> (a, b -> SqlExpr (Value Bool))
on = (,)
infix 9 `on`
data Lateral
data NotLateral
type family IsLateral a where
IsLateral (a -> SqlQuery b) = Lateral
IsLateral a = NotLateral
type family ErrorOnLateral a :: Constraint where
ErrorOnLateral (a -> SqlQuery b) = TypeError ('Text "LATERAL can only be used for INNER, LEFT, and CROSS join kinds.")
ErrorOnLateral _ = ()
{-- Type class magic to allow the use of the `InnerJoin` family of data constructors in from --}
class ToFrom a where
type ToFromT a
toFrom :: a -> From (ToFromT a)
-- @since 3.4.0.1
type family FromOnClause a where
FromOnClause (a, b -> SqlExpr (Value Bool)) = b
FromOnClause a = TypeError ('Text "Missing ON clause")
instance {-# OVERLAPPABLE #-} ToFrom (InnerJoin a b) where
type ToFromT (InnerJoin a b) = FromOnClause b
toFrom = undefined
instance {-# OVERLAPPABLE #-} ToFrom (LeftOuterJoin a b) where
type ToFromT (LeftOuterJoin a b) = FromOnClause b
toFrom = undefined
instance {-# OVERLAPPABLE #-} ToFrom (FullOuterJoin a b) where
type ToFromT (FullOuterJoin a b) = FromOnClause b
toFrom = undefined
instance {-# OVERLAPPABLE #-} ToFrom (RightOuterJoin a b) where
type ToFromT (RightOuterJoin a b) = FromOnClause b
toFrom = undefined
instance ToFrom (From a) where
type ToFromT (From a) = a
toFrom = id
instance
( ToAlias a
, ToAliasReference a
, SqlSelect a r
)
=>
ToFrom (SqlQuery a)
where
type ToFromT (SqlQuery a) = a
toFrom = SubQuery
instance
( SqlSelect c r
, ToAlias c
, ToAliasReference c
, ToSetOperation a c
, ToSetOperation b c
, c ~ SetOperationT a
)
=>
ToFrom (Union a b)
where
type ToFromT (Union a b) = SetOperationT a
toFrom u = SqlSetOperation $ toSetOperation u
instance
( SqlSelect c r
, ToAlias c
, ToAliasReference c
, ToSetOperation a c
, ToSetOperation b c
, c ~ SetOperationT a
)
=>
ToFrom (UnionAll a b)
where
type ToFromT (UnionAll a b) = SetOperationT a
toFrom u = SqlSetOperation $ toSetOperation u
instance
( SqlSelect c r
, ToAlias c
, ToAliasReference c
, ToSetOperation a c
, ToSetOperation b c
, c ~ SetOperationT a
)
=>
ToFrom (Intersect a b)
where
type ToFromT (Intersect a b) = SetOperationT a
toFrom u = SqlSetOperation $ toSetOperation u
instance
( SqlSelect c r
, ToAlias c
, ToAliasReference c
, ToSetOperation a c
, ToSetOperation b c
, c ~ SetOperationT a
)
=>
ToFrom (Except a b)
where
type ToFromT (Except a b) = SetOperationT a
toFrom u = SqlSetOperation $ toSetOperation u
instance (SqlSelect a r, ToAlias a, ToAliasReference a) => ToFrom (SqlSetOperation a) where
type ToFromT (SqlSetOperation a) = a
-- If someone uses just a plain SelectQuery it should behave like a normal subquery
toFrom (SelectQueryP _ q) = SubQuery q
-- Otherwise use the SqlSetOperation
toFrom q = SqlSetOperation q
class ToInnerJoin lateral lhs rhs res where
toInnerJoin :: Proxy lateral -> lhs -> rhs -> (res -> SqlExpr (Value Bool)) -> From res
instance ( SqlSelect b r
, ToAlias b
, ToAliasReference b
, ToFrom a
, ToFromT a ~ a'
) => ToInnerJoin Lateral a (a' -> SqlQuery b) (a' :& b) where
toInnerJoin _ lhs q on' = InnerJoinFromLateral (toFrom lhs) (q, on')
instance (ToFrom a, ToFromT a ~ a', ToFrom b, ToFromT b ~ b')
=> ToInnerJoin NotLateral a b (a' :& b') where
toInnerJoin _ lhs rhs on' = InnerJoinFrom (toFrom lhs) (toFrom rhs, on')
instance (ToInnerJoin (IsLateral b) a b b') => ToFrom (InnerJoin a (b, b' -> SqlExpr (Value Bool))) where
type ToFromT (InnerJoin a (b, b' -> SqlExpr (Value Bool))) = FromOnClause (b, b' -> SqlExpr(Value Bool))
toFrom (InnerJoin lhs (rhs, on')) = toInnerJoin (toProxy rhs) lhs rhs on'
where
toProxy :: b -> Proxy (IsLateral b)
toProxy _ = Proxy
-- @since 3.4.0.1
type family FromCrossJoin a b where
FromCrossJoin a (b -> SqlQuery c) = ToFromT a :& c
FromCrossJoin a b = ToFromT a :& ToFromT b
instance ( ToFrom a
, ToFrom b
, ToFromT (CrossJoin a b) ~ (ToFromT a :& ToFromT b)
) => ToFrom (CrossJoin a b) where
type ToFromT (CrossJoin a b) = FromCrossJoin a b
toFrom (CrossJoin lhs rhs) = CrossJoinFrom (toFrom lhs) (toFrom rhs)
instance {-# OVERLAPPING #-}
( ToFrom a
, ToFromT a ~ a'
, SqlSelect b r
, ToAlias b
, ToAliasReference b
) => ToFrom (CrossJoin a (a' -> SqlQuery b)) where
type ToFromT (CrossJoin a (a' -> SqlQuery b)) = FromCrossJoin a (a' -> SqlQuery b)
toFrom (CrossJoin lhs q) = CrossJoinFromLateral (toFrom lhs) q
class ToLeftJoin lateral lhs rhs res where
toLeftJoin :: Proxy lateral -> lhs -> rhs -> (res -> SqlExpr (Value Bool)) -> From res
instance ( ToFrom a
, ToFromT a ~ a'
, SqlSelect b r
, ToAlias b
, ToAliasReference b
, ToMaybe b
, mb ~ ToMaybeT b
) => ToLeftJoin Lateral a (a' -> SqlQuery b) (a' :& mb) where
toLeftJoin _ lhs q on' = LeftJoinFromLateral (toFrom lhs) (q, on')
instance ( ToFrom a
, ToFromT a ~ a'
, ToFrom b
, ToFromT b ~ b'
, ToMaybe b'
, mb ~ ToMaybeT b'
) => ToLeftJoin NotLateral a b (a' :& mb) where
toLeftJoin _ lhs rhs on' = LeftJoinFrom (toFrom lhs) (toFrom rhs, on')
instance ( ToLeftJoin (IsLateral b) a b b'
) => ToFrom (LeftOuterJoin a (b, b' -> SqlExpr (Value Bool))) where
type ToFromT (LeftOuterJoin a (b, b' -> SqlExpr (Value Bool))) = FromOnClause (b, b' -> SqlExpr(Value Bool))
toFrom (LeftOuterJoin lhs (rhs, on')) =
toLeftJoin (toProxy rhs) lhs rhs on'
where
toProxy :: b -> Proxy (IsLateral b)
toProxy _ = Proxy
instance ( ToFrom a
, ToFromT a ~ a'
, ToFrom b
, ToFromT b ~ b'
, ToMaybe a'
, ma ~ ToMaybeT a'
, ToMaybe b'
, mb ~ ToMaybeT b'
, ErrorOnLateral b
) => ToFrom (FullOuterJoin a (b, (ma :& mb) -> SqlExpr (Value Bool))) where
type ToFromT (FullOuterJoin a (b, (ma :& mb) -> SqlExpr (Value Bool))) = FromOnClause (b, (ma :& mb) -> SqlExpr(Value Bool))
toFrom (FullOuterJoin lhs (rhs, on')) = FullJoinFrom (toFrom lhs) (toFrom rhs, on')
instance ( ToFrom a
, ToFromT a ~ a'
, ToMaybe a'
, ma ~ ToMaybeT a'
, ToFrom b
, ToFromT b ~ b'
, ErrorOnLateral b
) => ToFrom (RightOuterJoin a (b, (ma :& b') -> SqlExpr (Value Bool))) where
type ToFromT (RightOuterJoin a (b, (ma :& b') -> SqlExpr (Value Bool))) = FromOnClause (b, (ma :& b') -> SqlExpr(Value Bool))
toFrom (RightOuterJoin lhs (rhs, on')) = RightJoinFrom (toFrom lhs) (toFrom rhs, on')
type family Nullable a where
Nullable (Maybe a) = a
Nullable a = a
class ToMaybe a where
type ToMaybeT a
toMaybe :: a -> ToMaybeT a
instance ToMaybe (SqlExpr (Maybe a)) where
type ToMaybeT (SqlExpr (Maybe a)) = SqlExpr (Maybe a)
toMaybe = id
instance ToMaybe (SqlExpr (Entity a)) where
type ToMaybeT (SqlExpr (Entity a)) = SqlExpr (Maybe (Entity a))
toMaybe = EMaybe
instance ToMaybe (SqlExpr (Value a)) where
type ToMaybeT (SqlExpr (Value a)) = SqlExpr (Value (Maybe (Nullable a)))
toMaybe = veryUnsafeCoerceSqlExprValue
instance (ToMaybe a, ToMaybe b) => ToMaybe (a :& b) where
type ToMaybeT (a :& b) = (ToMaybeT a :& ToMaybeT b)
toMaybe (a :& b) = (toMaybe a :& toMaybe b)
instance (ToMaybe a, ToMaybe b) => ToMaybe (a,b) where
type ToMaybeT (a, b) = (ToMaybeT a, ToMaybeT b)
toMaybe (a, b) = (toMaybe a, toMaybe b)
instance ( ToMaybe a , ToMaybe b , ToMaybe c) => ToMaybe (a,b,c) where
type ToMaybeT (a, b, c) = (ToMaybeT a, ToMaybeT b, ToMaybeT c)
toMaybe = to3 . toMaybe . from3
instance ( ToMaybe a , ToMaybe b , ToMaybe c , ToMaybe d) => ToMaybe (a,b,c,d) where
type ToMaybeT (a, b, c, d) = (ToMaybeT a, ToMaybeT b, ToMaybeT c, ToMaybeT d)
toMaybe = to4 . toMaybe . from4
instance ( ToMaybe a , ToMaybe b , ToMaybe c , ToMaybe d , ToMaybe e) => ToMaybe (a,b,c,d,e) where
type ToMaybeT (a, b, c, d, e) = (ToMaybeT a, ToMaybeT b, ToMaybeT c, ToMaybeT d, ToMaybeT e)
toMaybe = to5 . toMaybe . from5
instance ( ToMaybe a
, ToMaybe b
, ToMaybe c
, ToMaybe d
, ToMaybe e
, ToMaybe f
) => ToMaybe (a,b,c,d,e,f) where
type ToMaybeT (a, b, c, d, e, f) = (ToMaybeT a, ToMaybeT b, ToMaybeT c, ToMaybeT d, ToMaybeT e, ToMaybeT f)
toMaybe = to6 . toMaybe . from6
instance ( ToMaybe a
, ToMaybe b
, ToMaybe c
, ToMaybe d
, ToMaybe e
, ToMaybe f
, ToMaybe g
) => ToMaybe (a,b,c,d,e,f,g) where
type ToMaybeT (a, b, c, d, e, f, g) = (ToMaybeT a, ToMaybeT b, ToMaybeT c, ToMaybeT d, ToMaybeT e, ToMaybeT f, ToMaybeT g)
toMaybe = to7 . toMaybe . from7
instance ( ToMaybe a
, ToMaybe b
, ToMaybe c
, ToMaybe d
, ToMaybe e
, ToMaybe f
, ToMaybe g
, ToMaybe h
) => ToMaybe (a,b,c,d,e,f,g,h) where
type ToMaybeT (a, b, c, d, e, f, g, h) = (ToMaybeT a, ToMaybeT b, ToMaybeT c, ToMaybeT d, ToMaybeT e, ToMaybeT f, ToMaybeT g, ToMaybeT h)
toMaybe = to8 . toMaybe . from8
-- | 'FROM' clause, used to bring entities into scope.
--
-- Internally, this function uses the `From` datatype and the
-- `ToFrom` typeclass. Unlike the old `Database.Esqueleto.from`,
-- this does not take a function as a parameter, but rather
-- a value that represents a 'JOIN' tree constructed out of
-- instances of `ToFrom`. This implementation eliminates certain
-- types of runtime errors by preventing the construction of
-- invalid SQL (e.g. illegal nested-@from@).
from :: ToFrom a => a -> SqlQuery (ToFromT a)
from parts = do
(a, clause) <- runFrom $ toFrom parts
Q $ W.tell mempty{sdFromClause=[clause]}
pure a
where
runFrom :: From a -> SqlQuery (a, FromClause)
runFrom e@Table = do
let ed = entityDef $ getVal e
ident <- newIdentFor . DBName . unEntityNameDB $ entityDB ed
let entity = EEntity ident
pure $ (entity, FromStart ident ed)
where
getVal :: From (SqlExpr (Entity ent)) -> Proxy ent
getVal = const Proxy
runFrom (SubQuery subquery) =
fromSubQuery NormalSubQuery subquery
runFrom (FromCte ident ref) =
pure (ref, FromIdent ident)
runFrom (SqlSetOperation operation) = do
(aliasedOperation, ret) <- aliasQueries operation
ident <- newIdentFor (DBName "u")
ref <- toAliasReference ident ret
pure (ref, FromQuery ident (operationToSql aliasedOperation) NormalSubQuery)
where
aliasQueries o =
case o of
SelectQueryP p q -> do
(ret, sideData) <- Q $ W.censor (\_ -> mempty) $ W.listen $ unQ q
prevState <- Q $ lift S.get
aliasedRet <- toAlias ret
Q $ lift $ S.put prevState
let p' =
case p of
Parens -> Parens
Never ->
if (sdLimitClause sideData) /= mempty
|| length (sdOrderByClause sideData) > 0 then
Parens
else
Never
pure (SelectQueryP p' $ Q $ W.WriterT $ pure (aliasedRet, sideData), aliasedRet)
SqlSetUnion o1 o2 -> do
(o1', ret) <- aliasQueries o1
(o2', _ ) <- aliasQueries o2
pure (SqlSetUnion o1' o2', ret)
SqlSetUnionAll o1 o2 -> do
(o1', ret) <- aliasQueries o1
(o2', _ ) <- aliasQueries o2
pure (SqlSetUnionAll o1' o2', ret)
SqlSetExcept o1 o2 -> do
(o1', ret) <- aliasQueries o1
(o2', _ ) <- aliasQueries o2
pure (SqlSetExcept o1' o2', ret)
SqlSetIntersect o1 o2 -> do
(o1', ret) <- aliasQueries o1
(o2', _ ) <- aliasQueries o2
pure (SqlSetIntersect o1' o2', ret)
operationToSql o info =
case o of
SelectQueryP p q ->
let (builder, values) = toRawSql SELECT info q
in (parensM p builder, values)
SqlSetUnion o1 o2 -> doSetOperation "UNION" info o1 o2
SqlSetUnionAll o1 o2 -> doSetOperation "UNION ALL" info o1 o2
SqlSetExcept o1 o2 -> doSetOperation "EXCEPT" info o1 o2
SqlSetIntersect o1 o2 -> doSetOperation "INTERSECT" info o1 o2
doSetOperation operationText info o1 o2 =
let (q1, v1) = operationToSql o1 info
(q2, v2) = operationToSql o2 info
in (q1 <> " " <> operationText <> " " <> q2, v1 <> v2)
runFrom (InnerJoinFrom leftPart (rightPart, on')) = do
(leftVal, leftFrom) <- runFrom leftPart
(rightVal, rightFrom) <- runFrom rightPart
let ret = leftVal :& rightVal
pure $ (ret, FromJoin leftFrom InnerJoinKind rightFrom (Just (on' ret)))
runFrom (InnerJoinFromLateral leftPart (q, on')) = do
(leftVal, leftFrom) <- runFrom leftPart
(rightVal, rightFrom) <- fromSubQuery LateralSubQuery (q leftVal)
let ret = leftVal :& rightVal
pure $ (ret, FromJoin leftFrom InnerJoinKind rightFrom (Just (on' ret)))
runFrom (CrossJoinFrom leftPart rightPart) = do
(leftVal, leftFrom) <- runFrom leftPart
(rightVal, rightFrom) <- runFrom rightPart
let ret = leftVal :& rightVal
pure $ (ret, FromJoin leftFrom CrossJoinKind rightFrom Nothing)
runFrom (CrossJoinFromLateral leftPart q) = do
(leftVal, leftFrom) <- runFrom leftPart
(rightVal, rightFrom) <- fromSubQuery LateralSubQuery (q leftVal)
let ret = leftVal :& rightVal
pure $ (ret, FromJoin leftFrom CrossJoinKind rightFrom Nothing)
runFrom (LeftJoinFrom leftPart (rightPart, on')) = do
(leftVal, leftFrom) <- runFrom leftPart
(rightVal, rightFrom) <- runFrom rightPart
let ret = leftVal :& (toMaybe rightVal)
pure $ (ret, FromJoin leftFrom LeftOuterJoinKind rightFrom (Just (on' ret)))
runFrom (LeftJoinFromLateral leftPart (q, on')) = do
(leftVal, leftFrom) <- runFrom leftPart
(rightVal, rightFrom) <- fromSubQuery LateralSubQuery (q leftVal)
let ret = leftVal :& (toMaybe rightVal)
pure $ (ret, FromJoin leftFrom LeftOuterJoinKind rightFrom (Just (on' ret)))
runFrom (RightJoinFrom leftPart (rightPart, on')) = do
(leftVal, leftFrom) <- runFrom leftPart
(rightVal, rightFrom) <- runFrom rightPart
let ret = (toMaybe leftVal) :& rightVal
pure $ (ret, FromJoin leftFrom RightOuterJoinKind rightFrom (Just (on' ret)))
runFrom (FullJoinFrom leftPart (rightPart, on')) = do
(leftVal, leftFrom) <- runFrom leftPart
(rightVal, rightFrom) <- runFrom rightPart
let ret = (toMaybe leftVal) :& (toMaybe rightVal)
pure $ (ret, FromJoin leftFrom FullOuterJoinKind rightFrom (Just (on' ret)))
fromSubQuery
::
( SqlSelect a r
, ToAlias a
, ToAliasReference a
)
=> SubQueryType -> SqlQuery a -> SqlQuery (a, FromClause)
fromSubQuery subqueryType subquery = do
-- We want to update the IdentState without writing the query to side data
(ret, sideData) <- Q $ W.censor (\_ -> mempty) $ W.listen $ unQ subquery
aliasedValue <- toAlias ret
-- Make a fake query with the aliased results, this allows us to ensure that the query is only run once
let aliasedQuery = Q $ W.WriterT $ pure (aliasedValue, sideData)
-- Add the FromQuery that renders the subquery to our side data
subqueryAlias <- newIdentFor (DBName "q")
-- Pass the aliased results of the subquery to the outer query
-- create aliased references from the outer query results (e.g value from subquery will be `subquery`.`value`),
-- this is probably overkill as the aliases should already be unique but seems to be good practice.
ref <- toAliasReference subqueryAlias aliasedValue
pure (ref , FromQuery subqueryAlias (\info -> toRawSql SELECT info aliasedQuery) subqueryType)
-- | @WITH@ clause used to introduce a [Common Table Expression (CTE)](https://en.wikipedia.org/wiki/Hierarchical_and_recursive_queries_in_SQL#Common_table_expression).
-- CTEs are supported in most modern SQL engines and can be useful
-- in performance tuning. In Esqueleto, CTEs should be used as a
-- subquery memoization tactic. When writing plain SQL, CTEs
-- are sometimes used to organize the SQL code, in Esqueleto, this
-- is better achieved through function that return 'SqlQuery' values.
--
-- @
-- select $ do
-- cte <- with subQuery
-- cteResult <- from cte
-- where_ $ cteResult ...
-- pure cteResult
-- @
--
-- __WARNING__: In some SQL engines using a CTE can diminish performance.
-- In these engines the CTE is treated as an optimization fence. You should
-- always verify that using a CTE will in fact improve your performance
-- over a regular subquery.
--
-- /Since: 3.4.0.0/
with :: ( ToAlias a
, ToAliasReference a
, SqlSelect a r
) => SqlQuery a -> SqlQuery (From a)
with query = do
(ret, sideData) <- Q $ W.censor (\_ -> mempty) $ W.listen $ unQ query
aliasedValue <- toAlias ret
let aliasedQuery = Q $ W.WriterT $ pure (aliasedValue, sideData)
ident <- newIdentFor (DBName "cte")
let clause = CommonTableExpressionClause NormalCommonTableExpression ident (\info -> toRawSql SELECT info aliasedQuery)
Q $ W.tell mempty{sdCteClause = [clause]}
ref <- toAliasReference ident aliasedValue
pure $ FromCte ident ref
-- | @WITH@ @RECURSIVE@ allows one to make a recursive subquery, which can
-- reference itself. Like @WITH@, this is supported in most modern SQL engines.
-- Useful for hierarchical, self-referential data, like a tree of data.
--
-- @
-- select $ do
-- cte <- withRecursive
-- (do $
-- person <- from $ Table \@Person
-- where_ $ person ^. PersonId ==. val personId
-- pure person
-- )
-- unionAll_
-- (\\self -> do $
-- (p :& f :& p2 :& pSelf) <- from self
-- \`InnerJoin\` $ Table \@Follow
-- \`on\` (\\(p :& f) ->
-- p ^. PersonId ==. f ^. FollowFollower)
-- \`InnerJoin\` $ Table \@Person
-- \`on\` (\\(p :& f :& p2) ->
-- f ^. FollowFollowed ==. p2 ^. PersonId)
-- \`LeftOuterJoin\` self
-- \`on\` (\\(_ :& _ :& p2 :& pSelf) ->
-- just (p2 ^. PersonId) ==. pSelf ?. PersonId)
-- where_ $ isNothing (pSelf ?. PersonId)
-- groupBy (p2 ^. PersonId)
-- pure p2
-- )
-- from cte
-- @
--
-- /Since: 3.4.0.0/
withRecursive :: ( ToAlias a
, ToAliasReference a
, SqlSelect a r
, RecursiveCteUnion unionKind
)
=> SqlQuery a
-> unionKind
-> (From a -> SqlQuery a)
-> SqlQuery (From a)
withRecursive baseCase unionKind recursiveCase = do
(ret, sideData) <- Q $ W.censor (\_ -> mempty) $ W.listen $ unQ baseCase
aliasedValue <- toAlias ret
let aliasedQuery = Q $ W.WriterT $ pure (aliasedValue, sideData)
ident <- newIdentFor (DBName "cte")
ref <- toAliasReference ident aliasedValue
let refFrom = FromCte ident ref
let recursiveQuery = recursiveCase refFrom
let clause = CommonTableExpressionClause RecursiveCommonTableExpression ident
(\info -> (toRawSql SELECT info aliasedQuery)
<> (unionKeyword unionKind, mempty)
<> (toRawSql SELECT info recursiveQuery)
)
Q $ W.tell mempty{sdCteClause = [clause]}
pure refFrom
{-# DEPRECATED ToAliasT "This type alias doesn't do anything. Please delete it. Will be removed in the next release." #-}
type ToAliasT a = a
-- Tedious tuple magic
class ToAlias a where
toAlias :: a -> SqlQuery a
instance ToAlias (SqlExpr (Value a)) where
toAlias v@(EAliasedValue _ _) = pure v
toAlias v = do
ident <- newIdentFor (DBName "v")
pure $ EAliasedValue ident v
instance ToAlias (SqlExpr (Entity a)) where
toAlias v@(EAliasedEntityReference _ _) = pure v
toAlias v@(EAliasedEntity _ _) = pure v
toAlias (EEntity tableIdent) = do
ident <- newIdentFor (DBName "v")
pure $ EAliasedEntity ident tableIdent
instance ToAlias (SqlExpr (Maybe (Entity a))) where
toAlias (EMaybe e) = EMaybe <$> toAlias e
instance (ToAlias a, ToAlias b) => ToAlias (a,b) where
toAlias (a,b) = (,) <$> toAlias a <*> toAlias b
instance ( ToAlias a
, ToAlias b
, ToAlias c
) => ToAlias (a,b,c) where
toAlias x = to3 <$> (toAlias $ from3 x)
instance ( ToAlias a
, ToAlias b
, ToAlias c
, ToAlias d
) => ToAlias (a,b,c,d) where
toAlias x = to4 <$> (toAlias $ from4 x)
instance ( ToAlias a
, ToAlias b
, ToAlias c
, ToAlias d
, ToAlias e
) => ToAlias (a,b,c,d,e) where
toAlias x = to5 <$> (toAlias $ from5 x)
instance ( ToAlias a
, ToAlias b
, ToAlias c
, ToAlias d
, ToAlias e
, ToAlias f
) => ToAlias (a,b,c,d,e,f) where
toAlias x = to6 <$> (toAlias $ from6 x)
instance ( ToAlias a
, ToAlias b
, ToAlias c
, ToAlias d
, ToAlias e
, ToAlias f
, ToAlias g
) => ToAlias (a,b,c,d,e,f,g) where
toAlias x = to7 <$> (toAlias $ from7 x)
instance ( ToAlias a
, ToAlias b
, ToAlias c
, ToAlias d
, ToAlias e
, ToAlias f
, ToAlias g
, ToAlias h
) => ToAlias (a,b,c,d,e,f,g,h) where
toAlias x = to8 <$> (toAlias $ from8 x)
{-# DEPRECATED ToAliasReferenceT "This type alias doesn't do anything. Please delete it. Will be removed in the next release." #-}
type ToAliasReferenceT a = a
-- more tedious tuple magic
class ToAliasReference a where
toAliasReference :: Ident -> a -> SqlQuery a
instance ToAliasReference (SqlExpr (Value a)) where
toAliasReference aliasSource (EAliasedValue aliasIdent _) = pure $ EValueReference aliasSource (\_ -> aliasIdent)
toAliasReference _ v@(ERaw _ _) = toAlias v
toAliasReference _ v@(ECompositeKey _) = toAlias v
toAliasReference s (EValueReference _ b) = pure $ EValueReference s b
instance ToAliasReference (SqlExpr (Entity a)) where
toAliasReference aliasSource (EAliasedEntity ident _) = pure $ EAliasedEntityReference aliasSource ident
toAliasReference _ e@(EEntity _) = toAlias e
toAliasReference s (EAliasedEntityReference _ b) = pure $ EAliasedEntityReference s b
instance ToAliasReference (SqlExpr (Maybe (Entity a))) where
toAliasReference s (EMaybe e) = EMaybe <$> toAliasReference s e
instance (ToAliasReference a, ToAliasReference b) => ToAliasReference (a, b) where
toAliasReference ident (a,b) = (,) <$> (toAliasReference ident a) <*> (toAliasReference ident b)
instance ( ToAliasReference a
, ToAliasReference b
, ToAliasReference c
) => ToAliasReference (a,b,c) where
toAliasReference ident x = fmap to3 $ toAliasReference ident $ from3 x
instance ( ToAliasReference a
, ToAliasReference b
, ToAliasReference c
, ToAliasReference d
) => ToAliasReference (a,b,c,d) where
toAliasReference ident x = fmap to4 $ toAliasReference ident $ from4 x
instance ( ToAliasReference a
, ToAliasReference b
, ToAliasReference c
, ToAliasReference d
, ToAliasReference e
) => ToAliasReference (a,b,c,d,e) where
toAliasReference ident x = fmap to5 $ toAliasReference ident $ from5 x
instance ( ToAliasReference a
, ToAliasReference b
, ToAliasReference c
, ToAliasReference d
, ToAliasReference e
, ToAliasReference f
) => ToAliasReference (a,b,c,d,e,f) where
toAliasReference ident x = to6 <$> (toAliasReference ident $ from6 x)
instance ( ToAliasReference a
, ToAliasReference b
, ToAliasReference c
, ToAliasReference d
, ToAliasReference e
, ToAliasReference f
, ToAliasReference g
) => ToAliasReference (a,b,c,d,e,f,g) where
toAliasReference ident x = to7 <$> (toAliasReference ident $ from7 x)
instance ( ToAliasReference a
, ToAliasReference b
, ToAliasReference c
, ToAliasReference d
, ToAliasReference e
, ToAliasReference f
, ToAliasReference g
, ToAliasReference h
) => ToAliasReference (a,b,c,d,e,f,g,h) where
toAliasReference ident x = to8 <$> (toAliasReference ident $ from8 x)
class RecursiveCteUnion a where
unionKeyword :: a -> TLB.Builder
instance RecursiveCteUnion (a -> b -> Union a b) where
unionKeyword _ = "\nUNION\n"
instance RecursiveCteUnion (a -> b -> UnionAll a b) where
unionKeyword _ = "\nUNION ALL\n"