title: MySQL "Duplicate Foreign Key", but key doesn't exist
body: <p>I need to create a foreign key, but executing the following results in the  error: "Error Code: 1826. Duplicate foreign key constraint name 'FK_ProjectBase_Program'"</p>
  
  <pre><code>alter table ipos5.ProjectBase 
        add constraint FK_ProjectBase_Program foreign key (Program) references Program(OID);
  </code></pre>
  
  <p>If I execute:</p>
  
  <pre><code>select * 
  from information_schema.TABLE_CONSTRAINTS
  where CONSTRAINT_TYPE = 'FOREIGN KEY'
  
  result = def    ipos5   FK_ProjectBase_Program  ipos5   projectbase FOREIGN KEY
  </code></pre>
  
  <p>I can see the existing key definition, but if I show the structure for the target TABLE_NAME, it is not there.
  This is on an active database with a large amount of data, using InnoDB, so dump/restore is a very last resort.
    I am using a 3rd party framework, which does not allow me to manually specify a foreign key name (so I HAVE to use the one specified), but my application errors during startup because it cannot create the key.
    Is there a way to rebuild the information_schema database? I am really hoping to avoid doing a dump and rebuild of the application database, as it is quite large.</p>