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],
    }),
}));

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?

18 Replies

hachoterOP•2y ago

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)

Kairu•2y ago

it basically just registers the relations within the query module

hachoterOP•2y ago

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?

Kairu•2y ago

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,
  },
})

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

hachoterOP•2y ago

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

Kairu•2y ago

pivot/join tables yeah

hachoterOP•2y ago

And specify unique constraints for one ot many?

Kairu•2y ago

constraints are separate to this

hachoterOP•2y ago

oh I see

Kairu•2y ago

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

hachoterOP•2y ago

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

Kairu•2y ago

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

hachoterOP•2y ago

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

Kairu•2y ago

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

Indexes & Constraints – DrizzleORM

Drizzle ORM | %s

hachoterOP•2y ago

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

Kairu•2y ago

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

Dan•2y ago

yes, you can add it to the migration manually won't change the types

runonce•2y ago

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

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I am confused on how the new relational queries works