title: Mysql delete constraint
body: <p>I have a table with below structure :</p>
  
  <pre><code>    CREATE TABLE `Lm_help` (
   `id` int(10) NOT NULL AUTO_INCREMENT,
   `section` int(10) NOT NULL,
   `language` int(10) NOT NULL,
   `title` varchar(255) NOT NULL,
   `text` text NOT NULL,
   `timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
   PRIMARY KEY (`id`),
   UNIQUE KEY `unique_help` (`section`,`language`),
   KEY `language_constraint` (`language`),
   CONSTRAINT `language_constraint` FOREIGN KEY (`language`) REFERENCES `Lm_languages` (`id`),
   CONSTRAINT `section_constraint` FOREIGN KEY (`section`) REFERENCES `Lm_help_sections` (`id`)
  ) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=latin1
  </code></pre>
  
  <p>I need to remove "unique_help" key, but I am getting foreign key constraint error.</p>
  
  <blockquote>
    <p>Due to this error I not able to remove anything among these,
    section_constraint, language_constraint, unique_help.</p>
  </blockquote>
  
  <p>Below are other tables that refer to this :</p>
  
  <pre><code>CREATE TABLE `Lm_languages` (
   `id` int(11) NOT NULL AUTO_INCREMENT,
   `name` varchar(255) NOT NULL,
   `code` varchar(255) NOT NULL,
   `status` int(11) DEFAULT NULL,
   `created_at` datetime NOT NULL,
   `updated_at` datetime NOT NULL,
   PRIMARY KEY (`id`)
  ) ENGINE=InnoDB AUTO_INCREMENT=6 DEFAULT CHARSET=latin1
  
  
  
  
  CREATE TABLE `Lm_help_sections` (
   `id` int(11) NOT NULL AUTO_INCREMENT,
   `name` varchar(255) NOT NULL,
   PRIMARY KEY (`id`)
  ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=latin1
  </code></pre>