# Why post\_number? **URL:** \ **Category:** Development\ **Created:** [November 7, 2016, 7:33pm UTC](https://meta.discourse.org/t/why-post-number/52634 "2016-11-07T19:33:26Z")\ **Posts on this page:** 1\ **Showing post:** 1
**Author:** ![Kevin\_Wildenradt](https://sea3.discourse-cdn.com/meta/user_avatar/meta.discourse.org/kevin_wildenradt/32/62507_2.png) [@Kevin\_Wildenradt](https://meta.discourse.org/u/Kevin_Wildenradt)\ **Post date:** [November 7, 2016, 7:33pm UTC](https://meta.discourse.org/t/why-post-number/52634/1 "2016-11-07T19:33:26Z")
I’ve noticed that all posts bear both a post\_id and a post\_number. I understand that post\_id is the unique identifier of the post in the entire forum, while post\_number is the number of the post in its topic. Posts identify themselves as replies to other posts by referencing the post\_number of another post in the reply\_to\_post\_number field. Whenever any topic (or section of posts from a topic) is retrieved from the server, it contains a sorted array of the post\_id’s of every post in the topic. The front end provides access to specific post\_numbers via the URL, but when such a URL is actually accessed the request made to the back end is in terms of post\_ids (presumably accessed from the above mentioned array). This is all well and good, but it seems like everything post\_number is used for could be accomplished with post\_id instead: post\_id’s are always increasing, so they can be used to determine the relative ordering of posts in a topic. Since they are globally unique they are certainly unique within each topic, and so could be used in a reply\_to\_post\_id that serves the same purpose as reply\_to\_post\_number. TLDR; What purpose does post\_number serve that could not be easily accomplished with post\_id? If there is none then removing it would streamline the data model, which would seem to be a good thing. --- _[View the full topic](https://meta.discourse.org/t/why-post-number/52634)._