postgresql - Postgres foreign keys / schema issue -

if create new schema on current database (management), why complain cross-database references?

management=# create schema mgschema; create schema  management=# alter table clients add column task_id int null references mgschema.tasks.id; error:  cross-database references not implemented: "mgschema.tasks.id" 

alter table clients add column task_id int null references mgschema.tasks.id; 

the references syntax in not correct, should use:

references reftable [ ( refcolumn ) ]