I am confused on how the new relational queries works

In the docs I see the following

import { pgTable, serial, text, integer, boolean } from 'drizzle-orm/pg-core';
import { relations } from 'drizzle-orm';
 
export const users = pgTable('users', {
    id: serial('id').primaryKey(),
    name: text('name'),
    invitedBy: integer('invited_by'),
});
 
export const usersRelations = relations(users, ({ one, many }) => ({
    invitee: one(users, {
        fields: [users.invitedBy],
        references: [users.id],
    }),
}));

What does the usersRelations do? in the actual query it is not used
Is it just to add the tables without specifying unique constraints on the id fields? does it add additional fields to the actual table? and is this required to use the with keyword in a query?

If I manage to understand it I will try to make time to push a pr to clarify the docs (unless it's clear and I am just being stupid)

it basically just registers the relations within the query module

But how does the drizzle instance know about it? if it's not used in the query I am assuming it's only used to modify the tables, so my question is in the above example what ends up happening in the database?

the drizzle instance knows about it because you must include all relations alongside your schema
i split my schema from my relations like so

import * as relations from "./relations"
import * as schema from "./schema"
export const db = drizzle(connection, {
  schema: {
    ...schema,
    ...relations,
  },
})

relations dont modify tables or the database, it just tells the relational query module what your relations are

So I still need to add the mapping tables (e.g. usersToGroups ) for many to many?

pivot/join tables yeah

And specify unique constraints for one ot many?

constraints are separate to this

oh I see

the relational queries dont require constraints, meaning it works on planetscale

I didn't find anything in the docs about constraints either

I meant unique constraints

thats cause constraints are part of the database schema, not the relations

So unrelated question how can I specify a unique constraint on a single field within the schema?

the docs say unique isnt currently implemented https://orm.drizzle.team/docs/indexes-constraints#unique

Oh bummer, seems like a basic feature, I guess as long as it doesn't change my types I can always modify the migrations

Thanks for your help

actually not sure, there seems to be a few unique exports from core, maybe one of the devs can chime in on that one

np

yes, you can add it to the migration manually

won't change the types

This is mentioned on the Foreign keys section of the docs:

relations are a higher level abstraction, they are used to define relations between tables on the application level only. They do not affect the database schema in any way and do not create foreign keys implicitly.

https://orm.drizzle.team/docs/rqb#foreign-keys