As written in the official documentation:
Indexes must be added to each partition with separate commands. This also means that there is no way to create a primary key, unique constraint, or exclusion constraint spanning all partitions; it is only possible to constrain each leaf partition individually.
Since primary keys are not supported on partitioned tables, foreign keys referencing partitioned tables are not supported, nor are foreign key references from a partitioned table to some other table.
Using the ON CONFLICT clause with partitioned tables will cause an error because unique or exclusion constraints can only be created on individual partitions. There is no support for enforcing uniqueness (or an exclusion constraint) across ...
