Database.SQLite.Simple.Interpolate

Interpolated SQLite queries

Documentation

isql :: QuasiQuoter

Quote an SQL statement with embedded antiquoted expressions.

The result of the quasiquoter is a tuple, containing the statement string and a list of parameters. For example:

>>> import Data.Char (toLower)
>>> [isql|SELECT field FROM !{map toLower "PEOPLE"} WHERE name = {map toLower "ELLIOT"} AND access IN @{["admin", "employee"]} LIMIT {10 :: Int}|]
("SELECT field FROM people WHERE name = ? AND access IN (?,?) LIMIT ?",[SQLText "elliot",SQLText "admin",SQLText "employee",SQLInteger 10])

The generated code is:

("SELECT field FROM people WHERE name = ? AND access IN (?,?) LIMIT ?", [toField (map toLower ELLIOT)] ++ toRow ["admin", "employee"] ++ [toField (10 :: Int)])

How the parser works:

• Any expression occurring between { and } will be replaced with a ? and passed as a query parameter using toField.
• Any expression occuring between @{ and } will be replaced with the right amount of ?, separated by commas and surrounded by parentheses (e.g. (?,?,?) for a ToRow instance with 3 fields). The expression gets converted to query parameters using toRow.
• Any expression occurring between !{ and } will be replaced with its value, bypassing the anti-injection mechanisms. Never use this one for user input!

Characters preceded by a backslash are treated literally. This enables the inclusion of the literal character { within your quoted text by writing it as \{. The literal sequence \{ may be written as \\{.

iquery :: QuasiQuoter

Invokes query with arguments provided by isql. The result is of type (Connection -> IO [r]).

iexecute :: QuasiQuoter

Invokes execute with arguments provided by isql. The result is of type (Connection -> IO ()).

ifold :: QuasiQuoter

Invokes fold with arguments provided by isql. The result is of type (a -> (a -> row -> IO a) -> Connection -> IO a).

quoteInterpolatedSql :: String -> Q Exp

The Template Haskell function used by isql.