How can I ensure that there is one-and-only-one row in DB table?

Question

I would like to ensure that my MySQL table named "myTable" has one-and-only-one row.

So I need to be able to do Update on this row but obviously Insert and Remove should be not possible.

I am asking this question because of this Stack Overflow answer

Thanks!

Answer 1

CREATE TABLE `myTable` (
  `id` enum('1') NOT NULL,
  `MyValue1` int(6) DEFAULT '0',
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COMMENT='The ENUM(''1'') construct as primary key is used to prevent that more than one row can be entered to the table';