Rails jsonb - Prevent JSON keys from reordering when jsonb is saved to Postgresql database

Question

I have a column amount_splits that I need to save my JSON to in the key order I've specified.

How do I prevent Rails / Postgres jsonb from auto sorting my JSON keys when I save it to the database? (for creating or updating)

It looks like it's trying to sort alphabetically, but does a poor job at it.

Here's what I'm saving:

{
    "str_fee": 3.17,       # key 1
    "eva_fee": 14.37,      # key 2
    "fran_royalty": 14.37, # key 3
    "fran_amount": 67.09   # key 4
}

This is how it actually saves:

{
    "eva_fee": 14.37,     # key 2
    "str_fee": 3.17,      # key 1
    "fran_amount": 67.09, # key 4
    "fran_royalty": 14.37 # key 3
}

Purpose:

Before you answer "sorting doesn't matter when the JSON is consumed on the receiving end", stop and think first please... and please read on

I need the keys to be sorted in the way I need them sorted because the client interface that consumes this JSON is displaying the JSON to developers that need the keys to be in the order that the documentation tells them its in. And the reason it needs to be in that order is to display the process of what calculations happened in which order first:

The correct order tells the developer:

The str_fee was applied first, then the eva_fee, then the fran_royalty... making fran_amount the ending amount.

But based on how jsonb sorts this, it incorrectly tells our developers that:

The eva_fee was applied first, then the str_fee, then the fran_amount... making fran_royalty the ending amount.

Answer 1

Actually they're not sorted alphabetically but rather by key length then alphabetically, that explains the order you get. The jsonb type has been create as a better version of the json type to write and access data and it's probably for indexation and search purpose that they change the keys order. If you want your keys order not to change, you can use the json type that does not change the order of the keys when storing the data in the database.

Hope it helps.