code: public ForeignKeyInformation getFKInfo(final String _fkName)
      {
          return (_fkName != null)
                 ? this.fkMap.get(_fkName.toUpperCase())
                 : null;
      }
docs: <p>Returns for given name of foreign key <code>_fkName</code> (of the
  SQL table) the information about the foreign key, or if the given name
  of foreign key is not defined, a <code>null</code> is returned.</p>
  <p>The name of the given foreign key is searched independently of upper
  and / or lower case.</p>
  
  @param _fkName   name of foreign key which is searched
  @return foreign key information
  @see #fkMap