How to set column mapping relation when generating entities in Haskell?

Question

I am trying to use Persistent to access my database. I know that Persistent can generate the code of entity, but there is something I can't generate so easily. Like I got a table which looks like:

CREATE TABLE `user` (
  `user_id` bigint(11) NOT NULL,
  `user_name` varchar(255) DEFAULT NULL,
  `user_password` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

then my haskell code like :

mkPersist sqlSettings [persistLowerCase|
User
  name String
  password String
  deriving Show
|]

These fields are different include the primary key, I want to set their mapping relation. The official page (https://www.yesodweb.com/book/persistent) doesn't say how to do it.

Need I write the code to define it instead of generating it?

Have you looked at [the documentation for persistent](http://hackage.haskell.org/package/persistent)? — Rein Henrichs, May 27 '19 at 16:15
I've click all the links on the page, none of them can tell the way..please — Jacky Wong, May 28 '19 at 01:57

score 0 · Answer 1 · answered May 28 '19 at 01:55

0

I've found it on this page https://github.com/yesodweb/persistent/blob/master/docs/Persistent-entity-syntax.md

I can do some customization follow these syntax.

answered May 28 '19 at 01:55

Jacky Wong

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How to set column mapping relation when generating entities in Haskell?

1 Answers1