Safe Haskell	None
Language	Haskell2010

Hasql.DynamicStatements.Snippet

Synopsis

data Snippet
param :: DefaultParamEncoder param => param -> Snippet
encoderAndParam :: NullableOrNot Value param -> param -> Snippet
sql :: ByteString -> Snippet

Documentation

data Snippet Source #

Composable SQL snippet with parameters injected. Abstracts over placeholders and matching of encoders.

It has an instance of IsString, so having the OverloadedStrings extension enabled you can construct it directly from string literals.

Here's an example:

selectSubstring :: Text -> Maybe Int32 -> Maybe Int32 -> Snippet
selectSubstring string from to =
  "select substring(" <> param string <>
  foldMap (\ x -> " from " <> param x) from <>
  foldMap (\ x -> " for " <> param x) to <>
  ")"

Having a decoder you can lift it into Statement using dynamicallyParameterized or directly execute it in Session using dynamicallyParameterizedStatement.

Instances

Instances details

IsString Snippet Source #
Instance details Defined in Hasql.DynamicStatements.Snippet.Defs Methods fromString :: String -> Snippet
Semigroup Snippet Source #
Instance details Defined in Hasql.DynamicStatements.Snippet.Defs Methods (<>) :: Snippet -> Snippet -> Snippet sconcat :: NonEmpty Snippet -> Snippet stimes :: Integral b => b -> Snippet -> Snippet
Monoid Snippet Source #
Instance details Defined in Hasql.DynamicStatements.Snippet.Defs Methods mempty :: Snippet mappend :: Snippet -> Snippet -> Snippet mconcat :: [Snippet] -> Snippet

param :: DefaultParamEncoder param => param -> Snippet Source #

Parameter encoded using an implicitly derived encoder from the type.

encoderAndParam :: NullableOrNot Value param -> param -> Snippet Source #

Parameter with an explicitly defined encoder.

sql :: ByteString -> Snippet Source #

SQL chunk in ASCII.