Thanks for working on Selda! It's been a lot of fun to work with it!
The following example SQLite query for casting UTCTimes to DATETIMEs fails:
select CAST ("2023-02-10 06:02:55" as DATETIME);
As far as I understand it, this is because SQLite doesn't support anything beyond text and numbers. Other databases, like MySQL support the cast just fine!
The code to insert the invalid data is roughly the following:
data Person = Person {
pk :: ID Person,
birthday :: Maybe UTCTime -- having this be just a `UTCTime` inserts okay, it's that CAST as DATETIME because of `just` that causes issues
} deriving (Generic, Show)
instance SqlRow Challenge
persons = Selda.table "person" [#pk :- autoPrimary]
main = do
time <- getCurrentTime
withSQLite "selda_db.db" <|
update
persons
(\p -> p #pk .== literal 1)
(\p -> p with [ #birthday :- just (literal time) ])
Which creates a query that looks something like
UPDATE `persons` SET `birthday` = CAST($1 AS DATETIME) WHERE (`pk` = $2)
What's interesting is that if you have birthday be a regular unwrapped UTCTime field, Selda doesn't do any casting, so the values insert just fine. (It would just do SET `birthday = $1, since it doesn't go through just/cast)
Maybe I'm doing something wrong though, and there's a nice solution that I should be using!
[ #birthday :- just (literal time) ] can be replaced with [ #birthday :- fun "" (literal time) ] from Database.Selda.Unsafe is a workaround at least. Hopefully there's a nicer way!
Thanks for working on Selda! It's been a lot of fun to work with it!
The following example SQLite query for casting
UTCTime
s toDATETIME
s fails:As far as I understand it, this is because SQLite doesn't support anything beyond text and numbers. Other databases, like MySQL support the cast just fine!
The code to insert the invalid data is roughly the following:
Which creates a query that looks something like
What's interesting is that if you have
birthday
be a regular unwrappedUTCTime
field, Selda doesn't do any casting, so the values insert just fine. (It would just doSET `birthday = $1
, since it doesn't go throughjust
/cast
)Maybe I'm doing something wrong though, and there's a nice solution that I should be using!