title: Cannot add forrign key constraint
body: <p>My parent table creation is</p>
  
  <pre><code>create table product31
      (prod_id varchar(10), prod_name varchar(25))
      CHARACTER SET utf8 COLLATE utf8_unicode_ci
  </code></pre>
  
  <p>and my child table which want <code>foreign key</code> is</p>
  
  <pre><code>create table product32
      (prod_id varchar(10), prod_value varchar(25),
      constraint foreign key (prod_id) 
          references product31(prod_id) on update cascade on delete cascade)
      CHARACTER SET utf8 COLLATE utf8_unicode_ci
  </code></pre>
  
  <p>By running second table script i got error</p>
  
  <blockquote>
    <p>cannot add foreign key constraint</p>
  </blockquote>
  
  <p>plz help me</p>