{"action":"created","issue":{"url":"https://api.github.com/repos/Automattic/mongoose/issues/2562","labels_url":"https://api.github.com/repos/Automattic/mongoose/issues/2562/labels{/name}","comments_url":"https://api.github.com/repos/Automattic/mongoose/issues/2562/comments","events_url":"https://api.github.com/repos/Automattic/mongoose/issues/2562/events","html_url":"https://github.com/Automattic/mongoose/issues/2562","id":52880219,"number":2562,"title":"Is it possible to populate without `_id` ?","user":{"login":"mocheng","id":239291,"avatar_url":"https://avatars.githubusercontent.com/u/239291?v=3","gravatar_id":"","url":"https://api.github.com/users/mocheng","html_url":"https://github.com/mocheng","followers_url":"https://api.github.com/users/mocheng/followers","following_url":"https://api.github.com/users/mocheng/following{/other_user}","gists_url":"https://api.github.com/users/mocheng/gists{/gist_id}","starred_url":"https://api.github.com/users/mocheng/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/mocheng/subscriptions","organizations_url":"https://api.github.com/users/mocheng/orgs","repos_url":"https://api.github.com/users/mocheng/repos","events_url":"https://api.github.com/users/mocheng/events{/privacy}","received_events_url":"https://api.github.com/users/mocheng/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/Automattic/mongoose/labels/enhancement","name":"enhancement","color":"02d7e1"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":27,"created_at":"2014-12-26T03:58:27Z","updated_at":"2015-11-06T17:35:43Z","closed_at":null,"body":"I checked the API http://mongoosejs.com/docs/populate.html and tried out. It seems that `populate` can only works on foreign `_id`. Even there is a `match` option, it just add more filtering condition on `_id` query condition. There is no way to just populate with fields not involved with `_id`.\r\n\r\nIn my project, we keep the `_id` as ObjectId and has another field as auto-increment Number. For example, `customers` model has `_id` as Object and `cuid` as incremental number. Other collections just reference to `cuid` not to `_id`. \r\n\r\nIs would be great to be able to customize this?\r\nIs there any design limitation causing this feature missing?"},"comment":{"url":"https://api.github.com/repos/Automattic/mongoose/issues/comments/154480748","html_url":"https://github.com/Automattic/mongoose/issues/2562#issuecomment-154480748","issue_url":"https://api.github.com/repos/Automattic/mongoose/issues/2562","id":154480748,"user":{"login":"justvisiting","id":6187451,"avatar_url":"https://avatars.githubusercontent.com/u/6187451?v=3","gravatar_id":"","url":"https://api.github.com/users/justvisiting","html_url":"https://github.com/justvisiting","followers_url":"https://api.github.com/users/justvisiting/followers","following_url":"https://api.github.com/users/justvisiting/following{/other_user}","gists_url":"https://api.github.com/users/justvisiting/gists{/gist_id}","starred_url":"https://api.github.com/users/justvisiting/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/justvisiting/subscriptions","organizations_url":"https://api.github.com/users/justvisiting/orgs","repos_url":"https://api.github.com/users/justvisiting/repos","events_url":"https://api.github.com/users/justvisiting/events{/privacy}","received_events_url":"https://api.github.com/users/justvisiting/received_events","type":"User","site_admin":false},"created_at":"2015-11-06T17:35:43Z","updated_at":"2015-11-06T17:35:43Z","body":"+1"}}