Database.Groundhog.Generic.Sql

This module defines the functions which are used only for backends creation.

SQL rendering utilities

renderCond :: SqlDb db => RenderConfig -> Cond db r -> Maybe (RenderS db r)

Renders conditions for SQL backend. Returns Nothing if the fields don't have any columns.

defaultShowPrim :: PersistValue -> String

renderOrders :: SqlDb db => RenderConfig -> [Order db r] -> RenderS db r

renderUpdates :: SqlDb db => RenderConfig -> [Update db r] -> Maybe (RenderS db r)

renderFields :: StringLike s => (s -> s) -> [(String, DbType)] -> s

renderChain :: RenderConfig -> FieldChain -> [Utf8] -> [Utf8]

renderExpr :: SqlDb db => RenderConfig -> UntypedExpr db r -> RenderS db r

renderExprPriority :: SqlDb db => RenderConfig -> Int -> UntypedExpr db r -> RenderS db r

renderExprExtended :: SqlDb db => RenderConfig -> Int -> UntypedExpr db r -> [RenderS db r]

renderPersistValue :: PersistValue -> RenderS db r

mkExprWithConf :: (SqlDb db, PersistField a) => (RenderConfig -> Int -> Expr db r a) -> Expr db r a

Helps creating an expression which depends on render configuration. It can be used in pair with prerenderExpr. myExpr x = mkExprWithConf $ conf _ -> let x' = prerenderExpr conf x in x' + x' * x' @

prerenderExpr :: SqlDb db => RenderConfig -> Expr db r a -> Expr db r a

If we reuse complex expression several times, prerendering it saves time. RenderConfig can be obtained with mkExprWithConf

intercalateS :: StringLike s => s -> [s] -> s

commasJoin :: StringLike s => [s] -> s

flatten :: StringLike s => (s -> s) -> (String, DbType) -> [s] -> [s]

data RenderS db r

Constructors

RenderS

Fields

getQuery :: Utf8

getValues :: [PersistValue] -> [PersistValue]

Instances

IsString (RenderS db r)

Monoid (RenderS db r)

StringLike (RenderS db r)

newtype Utf8

Datatype for incremental building SQL queries

Constructors

Utf8 Builder

Instances

Eq Utf8

Show Utf8

IsString Utf8

Monoid Utf8

StringLike Utf8

newtype RenderConfig

Constructors

RenderConfig

Fields

esc :: Utf8 -> Utf8

fromUtf8 :: Utf8 -> ByteString

class (Monoid a, IsString a) => StringLike a where

Methods

fromChar :: Char -> a

Instances

StringLike String

StringLike Utf8

StringLike (RenderS db r)

fromString :: IsString a => String -> a

(<>) :: Monoid m => m -> m -> m infixr 6

An infix synonym for mappend.

Since: 4.5.0.0

function :: SqlDb db => String -> [UntypedExpr db r] -> Snippet db r

operator :: (SqlDb db, Expression db r a, Expression db r b) => Int -> String -> a -> b -> Snippet db r

parens :: Int -> Int -> RenderS db r -> RenderS db r

mkExpr :: SqlDb db => Snippet db r -> Expr db r a

newtype Snippet db r

Escape function, priority of the outer operator. The result is a list for the embedded data which may expand to several RenderS.

Constructors

Snippet (RenderConfig -> Int -> [RenderS db r])

class (DbDescriptor db, QueryRaw db ~ Snippet db) => SqlDb db where

This class distinguishes databases which support SQL-specific expressions. It contains ad hoc members for features whose syntax differs across the databases.

Methods

append :: (ExpressionOf db r a String, ExpressionOf db r b String) => a -> b -> Expr db r String

signum' :: (ExpressionOf db r x a, Num a) => x -> Expr db r a

quotRem' :: (ExpressionOf db r x a, ExpressionOf db r y a, Integral a) => x -> y -> (Expr db r a, Expr db r a)

equalsOperator :: RenderS db r -> RenderS db r -> RenderS db r

notEqualsOperator :: RenderS db r -> RenderS db r -> RenderS db r

class SqlDb db => FloatingSqlDb db where

This class distinguishes databases which support trigonometry and other math functions. For example, PostgreSQL has them but Sqlite does not. It contains ad hoc members for features whose syntax differs across the databases.

Methods

log' :: (ExpressionOf db r x a, Floating a) => x -> Expr db r a

Natural logarithm

logBase' :: (ExpressionOf db r b a, ExpressionOf db r x a, Floating a) => b -> x -> Expr db r a

tableName :: StringLike s => (s -> s) -> EntityDef -> ConstructorDef -> s

Returns escaped table name optionally qualified with schema

mainTableName :: StringLike s => (s -> s) -> EntityDef -> s

Returns escaped main table name optionally qualified with schema