   `project_attribute_id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
   `project_attribute_name` VARCHAR(50) NULL,
   `project_attribute_value` VARCHAR(50) NULL,
-  `project_id` INT UNSIGNED NULL,
+  `project_id` INT UNSIGNED NOT NULL,
   PRIMARY KEY (`project_attribute_id`),
   UNIQUE INDEX `project_attribute_name_UNIQUE` (`project_attribute_name` ASC),
   INDEX `fk_project_attribute_1_idx` (`project_id` ASC),

  CONSTRAINT `fk_library_attribute_1`
    FOREIGN KEY (`experiment_id`)
    REFERENCES `igfdb`.`experiment` (`experiment_id`)
    ON DELETE SET NULL
    ON UPDATE CASCADE)
ENGINE = InnoDB CHARSET=UTF8;


  `experiment_attribute_id` INT UNSIGNED NOT NULL AUTO_INCREMENT,
  `experiment_attribute_name` VARCHAR(30) NULL,
  `experiment_attribute_value` VARCHAR(50) NULL,
  `experiment_id` INT UNSIGNED NOT NULL,
  PRIMARY KEY (`experiment_attribute_id`),
  UNIQUE INDEX `library_attribute_name_UNIQUE` (`experiment_attribute_name` ASC),
  INDEX `fk_library_attribute_1_idx` (`experiment_id` ASC),
