The binding is the shared schema

const User = entity('User', users)

entity(name, table, { fields?, relations?, computed? }) derives an Effect Schema from the Drizzle table with drizzle-orm/effect-schema and exposes the table's columns as Remote fields.

The returned binding is simultaneously:

Drizzle table binding
        +
Remote EntityDescriptor
        +
relation/computed metadata

That is why this works without a second Entity declaration:

const UserSummary = User.select({
  id: true,
  name: true,
})

A table must expose an id column. Every entity read selects the primary key for normalization even when the client did not explicitly ask for id.

Use fields when the Remote schema should be narrower than the table or should use an application-specific codec:

import { Schema } from 'effect'

const User = entity('User', users, {
  fields: {
    id: UserId,
    name: Schema.String,
  },
})

Relation/computed fields are derived on top of that map.

Definition-time checks reject ambiguous bindings such as a relation/computed name colliding with a scalar field, a computed field naming an invalid relation, or a nullable singular foreign key not marked nullable.