title: Cannot make foreign key field nullable with Sequel Pro
body: <p>I'm having a defined relation to my user table as foreign key, but they don't necessarily need to be set. I.e. there must not be a related record.</p>
  
  <p>In my MySQL editor (Sequel Pro) I cannot make the addressId "allow null". It ignores the input. Im using newest version.</p>
  
  <p>When I create a new entry in the User table without an addressId, it says "Cannot add or update a child row: a foreign key constraint fails...". But I want to be able to add a User without an Address! Is that possible?</p>
  
  <p>Or should I simply remove the foreign keys? What is the drawback of that?</p>
  
  <pre><code>CREATE TABLE `User1` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `name` varchar(200) DEFAULT NULL,
    `email` varchar(255) DEFAULT NULL,
    `password` char(32) DEFAULT NULL,
    `addressId` int(11) NULL DEFAULT '0',
    `created` datetime DEFAULT NULL,
    `activated` datetime DEFAULT NULL,
    `lastLogin` datetime DEFAULT NULL,
    PRIMARY KEY (`id`,`addressId`),
    KEY `FK_User_Locale` (`localeId`),
    KEY `FK_User_Address` (`addressId`),
    CONSTRAINT `FK_User_Address` FOREIGN KEY (`addressId`) REFERENCES `Address` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION
  ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
  </code></pre>