Люди, ну кто подскажет, в чёт тут "косяк" - так сказать.....

Create table PREPOD (
"FAN" CHAR(50) not null PRIMARY KEY,
"Nam1" CHAR(60) NOT NULL,
"Nam2" CHAR (65) NOT NULL,
"NOTE" BLOB(400,1)
);
COMMIT;

CREATE TABLE PREDM (
"ID" SMALLINT NOT NULL PRIMARY KEY,
"PREDM" CHAR(150) NOT NULL,
"PREPOD" CHAR(50) NOT NULL,
"FAKULT" CHAR(120) NOT NULL,
"NOTE" BLOB(400,1),
FOREIGN KEY ("PREPOD") REFERENCES FAN ("PREPOD") ON UPDATE CASCADE ON DELETE SET NULL
);
COMMIT;

Выдаёт ошибку:

Unsuccessful metadata update
could not find UNIQUE INDEX with specified columns
Statement: CREATE TABLE PREDM (......