[firebase-br] Erro na criação de Constraint FK

[Mariana]

Amigos....

Estou criando uma tabela e quando tento criar a Constraint fica acusando o erro:

TABELA:

CREATE TABLE CT0D000(
   NRCHA    INTEGER NOT NULL,
   CDUSURET DM_CDUSU,
   CDUSULDR DM_CDUSU,
   DTCHA    DM_DATA,
   HRCHA    DM_DATA
);

ALTER TABLE CT0D000 ADD CONSTRAINT "PK_CT0D000" PRIMARY KEY ("NRCHA");

ALTER TABLE CT0D000 ADD CONSTRAINT "FK_CT0D000_0" FOREIGN KEY (NRCHA) REFERENCES CT03000 (NRCHA) ON UPDATE CASCADE;

Erro:
---------- STATEMENT ----------
alter table CT0D000
add constraint FK_CT0D000_0
foreign key (NRCHA)
references CT03000(NRCHA)
on update CASCADE

---------- ERROR MESSAGE ----------
This operation is not defined for system tables.
unsuccessful metadata update.
STORE RDB$REF_CONSTRAINTS failed.
action cancelled by trigger (1) to preserve data integrity.
Name of Referential Constraint not defined in constraints table.

Será que alguém pode me ajudar?

Grata

MAriana