On Sat, Dec 27, 2014 at 11:23:36AM +0000, Tom Ellis wrote:
PS. I started looking into Opaleye as a possible DSL and would appreciate any help you can give me in figuring out how to represent arrays in that. I am assuming I need to do something with queryRunnerColumn but I was not able to understand the example.
This is indeed somewhat fiddly to do because it requires fiddling with the implementation of postgresql-simple instances. Unfortunately that library does not provide us with enough primitives to do this directly.
OK, I just pushed a patch to GitHub https://github.com/tomjaguarpaw/haskell-opaleye Now you can do the below. You can't actually do anything with your arrays yet except just read them from tables and return them from `runQuery` but let me know what functionality you want and I will endevour to support it. import Database.PostgreSQL.Simple (execute_, ConnectInfo(..), connect) import Data.String (fromString) import Opaleye connectInfo :: ConnectInfo connectInfo = ConnectInfo { connectHost = "localhost" , connectPort = 25433 , connectUser = "tom" , connectPassword = "tom" , connectDatabase = "opaleye_test" } table :: Table (Column (PGArray (PGArray PGInt4))) (Column (PGArray (PGArray PGInt4))) table = Table "arraytable" (required "colname") query :: Query (Column (PGArray (PGArray PGInt4))) query = queryTable table main :: IO () main = do conn <- connect connectInfo let q = execute_ conn . fromString q "DROP TABLE IF EXISTS arraytable" q "CREATE TABLE arraytable (colname integer[][])" q "INSERT INTO arraytable VALUES ('{{1,2}, {3,4}}'), ('{{5,6}, {7,8}}')" results' <- runQuery conn query :: IO [[[Int]]] print results' -- ghci> main -- [[[1,2],[3,4]],[[5,6],[7,8]]]