The application probably still treats id as unique, but nothing in the schema guarantees it. And you can’t recover the guarantee with a separate UNIQUE (id) constraint: both MySQL and PostgreSQL require every unique constraint on a partitioned table to include the partition key columns. The uniqueness property has effectively been traded away.
MySQL has AUTO_INCREMENT [1]
PostgreSQL has SERIAL [2] and CREATE SEQUENCE [3]
What am I missing?
[1] https://dev.mysql.com/doc/refman/8.4/en/example-auto-increme...
[2] https://www.postgresql.org/docs/18/datatype-numeric.html#DAT...
[3] https://www.postgresql.org/docs/18/sql-createsequence.html