CREATE TABLE IF NOT EXISTS `mydb`.`properties_posts_rel` (
  `post_id` INT UNSIGNED NOT NULL,
  `property_id` INT UNSIGNED NOT NULL,
  PRIMARY KEY (`post_id`, `property_id`),
  INDEX `rel_property_idx` (`property_id` ASC),
  CONSTRAINT `rel_property`
    FOREIGN KEY (`property_id`)
    REFERENCES `mydb`.`properties` (`property_id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION,
  CONSTRAINT `rel_post`
    FOREIGN KEY (`post_id`)
    REFERENCES `mydb`.`posts` (`post_id`)
    ON DELETE NO ACTION
    ON UPDATE NO ACTION)
ENGINE = InnoDB;