then you get
getUsers :: App [User], which is a bit more manageable
note that you need to be more specific about the return type than just
a; since userspresumably refers to a table of some concrete type (I'm assuming Table User)
another thing to note is that your code will probably compose better if you also make your monad an instance of
MonadSelda and lift the withPostgreSQL call to the top (or at least, a bit further up); each call to it will open a new connection to the db, which means extra overhead and that any prepared statements will need to be recompiled
sorry about the late response, things have been a bit hectic lately
(and also, there's this lovely bug WRT migrating indexes until the next release: valderman/selda#107)
I get this:
λ❯ runReaderT (runApp getUsers) config
*** Exception: SqlError "error executing query `SELECT \"username_0\", \"uuid_1\", \"isAdmin_2\", \"password_3\", \"biography_4\" FROM (SELECT \"username\" AS \"username_0\", \"uuid\" AS \"uuid_1\", \"isAdmin\" AS \"isAdmin_2\", \"password\" AS \"password_3\", \"biography\" AS \"biography_4\" FROM \"users\") AS q0': ERROR: relation \"users\" does not exist\n"
whereas in the cockroach shell I've got:
root@localhost:26257/defaultdb> SELECT "username_0", "uuid_1", "isAdmin_2", "password_3", "biography_4" FROM (SELECT "username" AS "username_0", "uuid" AS "uuid_1", "isAdmin" AS "isAdmin_2", "password" AS "password_3", "biography" AS "biography_4" FROM "users") AS q0
username_0 | uuid_1 | isAdmin_2 | password_3 | biography_4
+------------+--------+-----------+------------+-------------+
(0 rows)
lemme double-check
could it be that cockroach is doing something almost-but-not-quite postgres compatible to switch databases?
they support postgres ORMs from other languages
(for what it's worth, I've also got this configuration:
λ❯ pgConnString . connectInfo $ config
"host=localhost port=26257 dbname=defaultdb user=euphrate connect_timeout=10 client_encoding=UTF8")
as for migration examples, there's not much to it; you need to give the source and destination tables as well as a selda expression to convert a row from the source table into one for the destination table, so something like this:
data User1 = User1 {name :: Text, password :: Text}
t1 :: Table User1
t1 = table "user" []
data User2 = User2 {name :: Text, password :: Text, age :: Int}
t2 :: Table User2
t2 = table "user" []
main = withPostgreSQL $ migrate t1 t2 (\user -> user `with` [#age := 0])
:)
that config looks sound to me; extremely weird that it can't find the users table
I give up for tonight
hi
I'm building my first app with selda and I ran into a problem: I'm using the
Any elegant way to solve this?
Thanks!
@valderman
I'm building my first app with selda and I ran into a problem: I'm using the
ID type in my entity and that prevents me from deriving generic aeson instances for it (as there appears to be no aeson or generic instances for ID).Any elegant way to solve this?
Thanks!
@valderman
also, not having those instances are a bit of an oversight, so I'll make a new release soonish which adds
Generic instances in selda, and To/FromJSON in selda-json
Hej @valderman
I'm trying to migrate to selda-0.5.0.0 but stack refuses to build selda-postgresql:
❯ stack build
Error: While constructing the build plan, the following exceptions were encountered:
In the dependencies for selda-postgresql-0.1.8.0:
selda-0.5.0.0 from stack configuration does not match >=0.4 && <0.5The dependency seems to be listed correctly in the cabal file in the repo (< 0.6):
https://github.com/valderman/selda/blob/master/selda-postgresql/selda-postgresql.cabal
But it's still 0.4 as seen on Hackage:
https://hackage.haskell.org/package/selda-postgresql
Thanks!
sorry about that