AT NAMESPACE LINK

CREATE TABLE at_namespace_link (
  namespacekey   dintkey,
  useskey        dintkey,
 
  CONSTRAINT at_pk_namespace_link PRIMARY KEY (namespacekey, useskey),
  CONSTRAINT at_fk_namespace_link_nsk FOREIGN KEY (namespacekey)
    REFERENCES at_namespace (id)
    ON UPDATE CASCADE
    ON DELETE CASCADE,
  CONSTRAINT at_fk_namespace_link_usk FOREIGN KEY (useskey)
    REFERENCES at_namespace (id)
    ON UPDATE CASCADE
    ON DELETE NO ACTION,
  CONSTRAINT at_chk_namespace_link CHECK (namespacekey <> useskey)
);