Feature Idea: Ability to Introspect Existing Postgres DB

[swheeler7]

With drizzle being supported it would be great if there was a tool that utilized the introspect command (https://orm.drizzle.team/kit-docs/commands#introspect--pull) to generate a minimal payloadcms collection config based on an existing database.

Use case would be for those migrating from a different system or who have database schemas set up already. In combination with related roadmap item #4300, this feature would ease the difficulty involved with migrating an existing relational schema to PayloadCMS.

[CenterSites]

That would be a great tool!

Using PayloadCMS with custom database schemas

PayloadCMS is database-agnostic and offers official adapters for MongoDB, SQLite, and since version 2.0, also PostgreSQL (using Drizzle ORM with node-postgres). By default, Payload automatically manages and updates its own schema—potentially dropping or renaming tables/columns that it doesn’t recognize.

However, you can preserve existing tables/data:
1. Use dbName: In your Payload collections, set the dbName property to point to an existing table instead of creating a new one.
2. Schema introspection & hooks: Run Drizzle’s introspection (drizzle-kit pull) to generate TypeScript definitions of your existing tables. Then, inject these into Payload’s schema via the beforeSchemaInit hook. This way, Payload “knows” about your existing tables and won’t drop them during schema migrations.