What happens when user changes value of a primary field

I understand that bubble keeps a unique ID for each entry, and that you can assign a field to be the primary field for referencing that particular entry.

  1. where does the primary field show up in the expression builder? while writing an expression i never saw an option to choose specific entries by its primary fields values.

  2. what if the user changes the value of the primary field of a specific entry, and i have expressions all over the app referring to this particular entry by using the primary field’ value (instead of using the ID), would it still point to that specific entry? or since it was changed, it lost it?

The “Primary Field” is just there for the Data Tab in the Editor, so that you can show a particular field when it is viewed from another table (so show email address when another table references the User etc).

It has no relevance to the database other than that, it isn’t a way of doing a secondary key.

Thanks @NigelG for clarifying