title: Using CONSTRAINT alogn with FOREIGN KEY
body: <p>I'm trying to understand the difference between creating a <code>FOREIGN KEY</code> this way:</p>
  
  <pre><code>CREATE TABLE child(
      id_child  INT NOT NULL,  
      id_parent INT 
      FOREIGN KEY(id_parent) REFERENCES parent(id_parent));
  </code></pre>
  
  <p>rather than this one:</p>
  
  <pre><code>CREATE TABLE child(
      id_child  INT NOT NULL,  
      id_parent INT 
      CONSTRAINT FK_id_parent FOREIGN KEY(id_parent) REFERENCES parent(id_parent));
  </code></pre>
  
  <p>If I use the first form it will create a <code>CONSTRAINT</code> anyway (Innodb indexes, or am I wrong? not so illustrated about indexes). So, what's the need to explicitly declare the <code>CONSTRAINT</code> or there's no reason to do it?</p>