title: Cannot truncate a table referenced in a foreign key constraint from empty table
body: <p>I have the following tables:</p>
  
  <pre><code>CREATE TABLE `companies_investorfundinground` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `funding_round_id` int(11) NOT NULL,
    `investor_id` int(11) NOT NULL,
    PRIMARY KEY (`id`),
    KEY `companies_funding_round_id_8edc4cc4_fk_companies_fundinground_id` (`funding_round_id`),
    KEY `companies_investor_investor_id_30d4fd3e_fk_companies_investor_id` (`investor_id`),
    CONSTRAINT `companies_funding_round_id_8edc4cc4_fk_companies_fundinground_id` FOREIGN KEY (`funding_round_id`) REFERENCES `companies_fundinground` (`id`),
    CONSTRAINT `companies_investor_investor_id_30d4fd3e_fk_companies_investor_id` FOREIGN KEY (`investor_id`) REFERENCES `companies_investor` (`id`)
  )
  
  
  CREATE TABLE `companies_fundinground` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `funding_round_code` varchar(32) COLLATE utf8mb4_unicode_ci DEFAULT NULL,
    PRIMARY KEY (`id`),
    KEY `companies_fundinground_447d3092` (`company_id`),
    CONSTRAINT `companies_company_id_36dd5970_fk_companies_company_entity_ptr_id` FOREIGN KEY (`company_id`) REFERENCES `companies_company` (`entity_ptr_id`)
  )
  </code></pre>
  
  <p>I was able to truncate companies_investorfundinground.</p>
  
  <p>I try to delete companies_fundinground but I get the error:</p>
  
  <blockquote>
    <p>Cannot truncate a table referenced in a foreign key constraint companies_funding_round_id_8edc4cc4_fk_companies_fundinground_id</p>
  </blockquote>
  
  <p>Why am I getting this error if companies_investorfundinground is completely truncated?</p>