Primary Key Standard

Purpose

The Primary Key Standard defines identifier rules for future database specifications.

Rules

Rule	Requirement
Stable identity	Primary keys must not change after creation.
Opaque identifiers	IDs should not encode mutable business meaning.
Module ownership	Owning module defines ID semantics for its aggregate or entity.
Public safety	Public API identifiers must not leak internal sequencing or sensitive data.
References	Cross-module references use stable IDs and do not imply ownership.

Identifier Guidance

• Prefer stable surrogate identifiers for aggregate roots and entities.
• Natural identifiers may be unique constraints but should not be the only identity when they can change.
• External provider identifiers are stored as provider references, not primary keys.
• Event, audit, idempotency, and outbox records require stable identifiers for traceability.

Key Flow

flowchart LR
    Aggregate[Aggregate Root]
    Id[Stable Primary Key]
    Table[(Owned Table)]
    Reference[Cross-Module Reference]

    Aggregate --> Id
    Id --> Table
    Id --> Reference

Non-Goals

This document does not choose UUID format, sequence strategy, database type, or Java ID class implementation.