Zasto ne mogu da unesem strani kljuc u Hijerarhiju?

CREATE TABLE NTRecepcioner (
IDRAD INTEGER NOT NULL,
CONSTRAINT PK_NTRecepcioner79 PRIMARY KEY (IDRAD)
);
CREATE TABLE NTHotel (
BRHOT INTEGER NOT NULL,
ADRHOT VARCHAR ( 255 ) NOT NULL,
NAZHOT VARCHAR ( 255 ) NOT NULL,
MESTOHOT VARCHAR ( 255 ) NOT NULL,
BRTELHOT INTEGER NOT NULL,
CONSTRAINT PK_NTHotel72 PRIMARY KEY (BRHOT)
);
CREATE TABLE NTRadnik (
IDRAD INTEGER NOT NULL,
IMER VARCHAR ( 255 ) NOT NULL,
PREZR VARCHAR ( 255 ) NOT NULL,
BRHOT INTEGER,
CONSTRAINT PK_NTRadnik74 PRIMARY KEY (IDRAD)
);
CREATE TABLE NTSobarica (
IDRAD INTEGER NOT NULL,
CONSTRAINT PK_NTSobarica80 PRIMARY KEY (IDRAD)
);
CREATE TABLE NTUpravnik (
IDRAD INTEGER NOT NULL,
CONSTRAINT PK_NTUpravnik81 PRIMARY KEY (IDRAD)
);
CREATE TABLE NTKonobar (
IDRAD INTEGER NOT NULL,
CONSTRAINT PK_NTKonobar78 PRIMARY KEY (IDRAD)
);
CREATE INDEX TC_NTRadnik64 ON NTRadnik (BRHOT);
ALTER TABLE NTRecepcioner ADD CONSTRAINT FK_NTRecepcioner53 FOREIGN KEY (IDRAD) REFERENCES NTRadnik (IDRAD) ON DELETE NO ACTION ON UPDATE NO ACTION;
ALTER TABLE NTRadnik ADD CONSTRAINT FK_NTRadnik51 FOREIGN KEY (BRHOT) REFERENCES NTHotel (BRHOT) ON DELETE NO ACTION ON UPDATE NO ACTION;
ALTER TABLE NTSobarica ADD CONSTRAINT FK_NTSobarica54 FOREIGN KEY (IDRAD) REFERENCES NTRadnik (IDRAD) ON DELETE NO ACTION ON UPDATE NO ACTION;
ALTER TABLE NTUpravnik ADD CONSTRAINT FK_NTUpravnik55 FOREIGN KEY (IDRAD) REFERENCES NTRadnik (IDRAD) ON DELETE NO ACTION ON UPDATE NO ACTION;
ALTER TABLE NTKonobar ADD CONSTRAINT FK_NTKonobar52 FOREIGN KEY (IDRAD) REFERENCES NTRadnik (IDRAD) ON DELETE NO ACTION ON UPDATE NO ACTION;

Ovo mi je DDL fajl,mene interesuje zasto nikako ne mogu da unesem kljuc u bazu npr za sobaricu? Napravila sam JSP stranicu za unos sobarice i su mi se izlistaju svi kljucevi koje pokupim iz Radnika i kad kazem da mi unese meni javi gresku...tj neki izuzetak . Avo primer te greske:
Caused by: java.sql.BatchUpdateException: Cannot add or update a child row: a foreign key constraint fails (`prerada`.`ntsobarica`, CONSTRAINT `FK_NTSobarica54` FOREIGN KEY (`IDRAD`) REFERENCES `ntradnik` (`IDRAD`) ON DELETE NO ACTION ON UPDATE NO ACTION)
at com.mysql.jdbc.ServerPreparedStatement.executeBatch(ServerPreparedStatement.java:665)
at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48)
at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:242)
... 30 more
Molim vas pomozite mi!!!!!!!!!!!!!