CREATE TABLE `vn`.`entryObservation` (
    id int NOT NULL AUTO_INCREMENT,
    entryFk int NOT NULL,
    observationTypeFk TINYINT(3) UNSIGNED,
    description TEXT,
    PRIMARY KEY (id),
    CONSTRAINT entry_id_entryFk
    FOREIGN KEY (entryFk) REFERENCES entry(id),
    CONSTRAINT observationType_id_observationTypeFk
    FOREIGN KEY (observationTypeFk) REFERENCES observationType(id)
);

ALTER TABLE `vn`.`entryObservation` 
ADD UNIQUE INDEX `entryFk_observationTypeFk_UNIQUE` (`entryFk` ASC,`observationTypeFk` ASC);