Why are object_id in photo table(fql) and object_id through graph api different? - facebook

Question

I queried a page with due permissions for its feed. There was a post with three photos. The response json was:
{
"id": "some_id",
"from": {
"category": "Tv show",
"name": "some_name",
"id": "some_id"
},
"message": "New post with 3 photos",
"picture": "some_link",
"link": "some_link",
"icon": "some_link",
"actions": [
{
"name": "Comment",
"link": "some_link"
},
{
"name": "Like",
"link": "some_link"
}
],
"privacy": {
"description": "Public",
"value": "EVERYONE",
"friends": "",
"networks": "",
"allow": "",
"deny": ""
},
"type": "photo",
"status_type": "mobile_status_update",
"object_id": "some_id",
"created_time": "2014-02-05T07:06:22+0000",
"updated_time": "2014-02-05T07:06:35+0000",
"likes": {
"data": [
{
"id": "some_id",
"name": "some_name"
}
],
"paging": {
"cursors": {
"after": "MTgyNDY2NjQ1MjM4MTc5",
"before": "MTgyNDY2NjQ1MjM4MTc5"
}
}
},
"comments": {
"data": [
{
"id": "some_id",
"from": {
"category": "Tv show",
"name": "some_name",
"id": "some_id"
},
"message": "With a comment and a like on it",
"can_remove": true,
"created_time": "2014-02-05T07:06:35+0000",
"like_count": 0,
"user_likes": false
}
],
"paging": {
"cursors": {
"after": "MQ==",
"before": "MQ=="
}
}
}
},
Firstly, I only got one object_id, whereas the post contained 3 photos. The object_id was of a single photo. I also queried through fql for object_id for that photo in photo table and the object_ids were not matching. Why is it so? What does object_id mean in both cases?

Answer 1

The Object ID for Posts will be different to the Object ID of the photos used in the post, as they are effectively different representations of the same thing. The id will be the ID of the page post, and the object_id will be the Album ID of the uploaded photos.
Try calling /{object_id}/photos to get the list of photos in the post.
A good way to test what each object_id represents is to go to http://www.facebook.com/{object_id} to see where it goes. It will either go to a page, post, album / media set, photo or an error page.