typedquery

Parser for SQL augmented with types

Monthly Downloads: 11

Programming language: Haskell

License: BSD 3-clause "New" or "Revised" License

Tags: Database    

README

typedquery

Parser for SQL augmented with types

Till it finalised I would recomend installing it: with cabal -f debug-typed-queries just to see what is gonig on. As the SQL parser is not complete, and will need a major lift to make it readable and sane... however it works fine for all queries I need.

This package provides base parsing facilities for possibly all *-simple database packages converting them into *-simpel-typed

• https://github.com/tolysz/mysql-simple-typed
• https://github.com/tolysz/sqlite-simple-typed
• https://github.com/tolysz/postgresql-simple-typed

example: https://github.com/tolysz/sqlite-simple-typed/blob/master/example/src/Main.hs

The basic idea is to start using SQL again, but use comemnts (--) to hide haskell annotation.

This started as QuasiQuotes excercise with the TH inpired printf.

• genJsonQuery produces [Value]
• genTypedQuery produces [(T1,...,Tn)] tuples, [T] or () all depending on the SQL query

If you do not provide value (or a mean to get on inside query you need to give it outside.

They do the same:

$(genJsonQuery "SET SESSION group_concat_max_len = ? ") conn (10000 :: Int)
$(genJsonQuery "SET SESSION group_concat_max_len = ? -- Int ") conn 10000
$(genJsonQuery "SET SESSION group_concat_max_len = ? -- Int  -- < 1000 ") conn
$(genJsonQuery "SET SESSION group_concat_max_len = ? -- < (1000 :: Int) ") conn

There is a basic syntax, and the base idea is to have a nice easy for eye syntax. It fires the correct execute or query with or without _ depending on the actual SQL syntax

The parser is not complete, I will try to add as many issues there are and try to fix it.

Adnotations start with -- as otherwise HeidiSQL was complaining, then > < ~ or just text.

syntax	equivalent
bal -- Type	(\v -> v :: Bla)
bla -- > f	(\v -> f bla )
bla -- Type -- > f	(\v -> (f bla):: Type )
? -- Type -- < var	??
? -- < var	??
? -- < var	??
? -- ~ verbatim	??

Eg.

$(genJsonQuery [qq| insert into some_table
  ( timeAsSQLfunction           -- ~ now ()
  , someInputfromAesonViaLens   -- Int  -- < v ^? (key "coolValue" . _Integral) ^. non 3 
  , someUserName                -- Text -- < someNameFromContext
  ) |]) conn

Translates to

execute conn [qq| insert into some_table
      ( timeAsSQLfunction, someInputfromAesonViaLens, someUserName )
      values ( now (), ?, ?) |] 
        [( (v ^? (key "coolValue" . _Integral) ^. non 3 ) :: Int, someNameFromContext Text)]