Description

When using the SCHEMA multi-tenancy strategy in Hibernate ORM, the database schema to use for each session is supposedly determined by the tenant identifier.

However, if quarkus.hibernate-orm.database.default-schema is set, that "default" schema becomes the mandatory schema everywhere, and overrides the schema inferred from the tenant identifier.

It should not.

See #15602 (comment)

Implementation ideas

• If there are cases where no tenant ID is defined, then we should only use the default schema in those cases.
• If there aren't such cases, we should forbid using quarkus.hibernate-orm.database.default-schema when schema-based multitenancy is enabled.