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Editorial Team
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Asked: 2026-06-02T06:08:36+00:00

I’m working on an app (Rails 3.2, Mongoid) that takes all (by all I

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I’m working on an app (Rails 3.2, Mongoid) that takes all (by all I mean ‘a lot’) photos from a user. First, we get the albums (<userid>/albums), then, for each album, we take the photos in it (<albumid>/photos), then, the user photos (<userid>/photos). Then we do some operations on each photo, and save them to a DB.

Right now, as a safety net, for each ‘orphan’ photo, I check if the photo is not already present, to avoid duplicates. The current check is done on the db with a exists query. However, is makes lots of db queries, and this is not acceptable. I tried to do it server side, using an array to keep track of the photos, but it was way slower (I used Array#select if my memory is correct).

So, two questions : 1/ Is this ‘safety net’ useful, or can I take for granted that the orphan photos cannot be duplicates ? I’m thinking yes, but I think the check is done for a reason.
2/ If I have to check in order to be sure that there is no duplicates in the database, how should I do it in order to be efficient ?

EDIT

Ok looks like there truly can be duplicates, so question 1/ is solved. Now about 2: is it possible to “guess” from the retrieved photo fields if it belongs to an album, even though there’s no field like album_id ? As in “if the photo is not from user and user is tagged in” -> orphan ?

Thanks for you time!

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1 Answer

  1. Editorial Team

    Yes you can 🙂

    From the documentation: Photo FQL table

    For a given photo with id XXXXXX:

    select owner,album_object_id from photo where object_id=XXXXXX

    If you don’t get anything, that means you queried a photo which is out of your

    access token reach (query a photo of someone else).

    You need user_photos permission to access the user photo or friends_photos to access one of the user friends photo.

    Otherwise, you should have the album id of that photo in album_object_id

    Make sure in the Graph API explorer to click the Get Access Token button and check the user_photos permission when you test the query.

    P.S.

    I have tested this on various photos just to be sure and all tests came back positive 🙂

    Link to test in Graph API explorer: 

    https://developers.facebook.com/tools/explorer/?method=GET&path=fql%3Fq%3Dselect%20owner%2Calbum_object_id%20from%20photo%20where%20object_id%3DXXXXXXXX

    (don’t forget to change the XXXXXXXX with the photo id)

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