How do you write a database migration to reference another table in another service as a foreign key access constraint.
CREATE TABLE tasks (
id UUID NOT NULL PRIMARY KEY,
uid UUID NOT NULL REFERENCES `users(id)` ON DELETE CASCADE
where uid is a foreign key from the table users in the
Unfortunately that’s not something that you can do. Postgres doesn’t support foreign key references across databases. If you want to use foreign keys the tables need to be inside the same database.
When building distributed systems you typically accept that you get weaker guarantees when it comes to foreign key constraints. For most applications that trade-off is worthwhile.