Method check_dependencies

sql/sql_cte.cc:299–360

*/

bool With_clause::check_dependencies()
{
  if (dependencies_are_checked)
    return false;
  /* 
    Look for for definitions with the same query name.
    When found report an error and return true immediately.
    For each table T defined in this with clause look for all other tables
    from the same with clause that are used in the specification of T.
    For each such table set the dependency bit in the dependency map of
    the with element for T.
  */
  for (With_element *with_elem= with_list.first;
       with_elem;
       with_elem= with_elem->next)
  {
    for (With_element *elem= with_list.first;
         elem != with_elem;
         elem= elem->next)
    {
      if (with_elem->get_name().streq(elem->get_name()))
      {
        my_error(ER_DUP_QUERY_NAME, MYF(0),
                 with_elem->get_name_str());
	return true;
      }
    }
    if (with_elem->check_dependencies_in_spec())
      return true;
  }
  /* Build the transitive closure of the direct dependencies found above */
  for (With_element *with_elem= with_list.first;
       with_elem;
       with_elem= with_elem->next)
    with_elem->derived_dep_map= with_elem->base_dep_map;
  for (With_element *with_elem= with_list.first;
       with_elem;
       with_elem= with_elem->next)
  {
    table_map with_elem_map=  with_elem->get_elem_map();
    for (With_element *elem= with_list.first; elem; elem= elem->next)
    {
      if (elem->derived_dep_map & with_elem_map)
        elem->derived_dep_map |= with_elem->derived_dep_map;
    }   
  }

  /*
    Mark those elements where tables are defined with direct or indirect
    recursion.
  */ 
  for (With_element *with_elem= with_list.first;
       with_elem;
       with_elem= with_elem->next)
  {
    if (with_elem->derived_dep_map & with_elem->get_elem_map())
      with_elem->is_recursive= true;
  }