CODEWITHSUNDEEP
haskell
aviaviavi
aviaviavi

Reputation: 308

How to access fields of a persist Entity in Haskell

I'm writing a REST API in Haskell with the Scotty framework. I have a persist table defined as 

share [mkPersist sqlSettings, mkMigrate "migrateAll"] [persistLowerCase|
User json
    username Text
    number Text
    group Text Maybe
    UniqueUsername username
    UniqueNumber number
    deriving(Show)
...
]

I then have a function to grab a user fetchUserByName :: Text -> IO (Entity User). What I'm not understanding is that if I have a variable user :: Entity User, how do I access any of the fields, like username for this user? I feel like this should be completely trivial yet I can't seem to find the answer online. Or am I just going about this the wrong way? Thank you.

Upvotes: 3

Views: 350

Answers (1)

jamshidh
jamshidh

Reputation: 12070

You can extract your User item using entityVal, then you can to the desired column using the record name (which I believe is always generated to be of the format of the format <tablename><columnname> in camelcase)

print $ userGroup $ entityVal user

Upvotes: 4

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