title: naming convention in constraint and index
body: <p>Can both index and constraint have the same name and  what is recommended naming convention</p>
  
  <pre><code>CREATE  TABLE IF NOT EXISTS `mydb`.`books` (
   `id` INT NOT NULL AUTO_INCREMENT ,
    `isbn` VARCHAR(45) NOT NULL ,
    `category_id` INT NOT NULL ,
    `publisher_id` INT NOT NULL ,
    `year` YEAR NULL ,
    PRIMARY KEY (`id`) ,
    INDEX `fk_books_category_id` (`category_id` ASC) ,
    INDEX `fk_books_publisher_id` (`publisher_id` ASC) ,
    CONSTRAINT `fk_books_category_id`
      FOREIGN KEY (`category_id` )
      REFERENCES `mydb`.`categories` (`id` )
      ON DELETE NO ACTION
      ON UPDATE NO ACTION,
    CONSTRAINT `fk_books_publisher_id`
      FOREIGN KEY (`publisher_id` )
      REFERENCES `mydb`.`publishers` (`id` )
      ON DELETE NO ACTION
      ON UPDATE NO ACTION)
  ENGINE = InnoDB;
  </code></pre>