I use Persistent orm with scotty web framework.
I want to get value from db by id. These id are coming to me from GET request
There are "get" function that takes "Key Entity" variable and returns "Maybe Entity".
I use following code to get value from db
k <- keyFromValues $ [(PersistInt64 myOwnIntVarFromRequest)]
case k of
Left _ -> {-some processing-}
Right x -> do
t <- liftIO . runDb $ get (x::Key Post) --Post is one of my models
case t of
Nothing -> {-processing-}
Just x -> {-processing-}
These code is extremly ugly. But i don't know how to do it better
So my question is how obtain variable of type "Key Entity" without calling keyFromValues.
PS Sorry for my poor English
You can use toSqlKey for that.
来源:https://stackoverflow.com/questions/28068447/haskell-persistent-how-get-entity-from-db-by-key-if-i-have-key-in-integer-varia