~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008 Sun Microsystems

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; version 2 of the License.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

#include "config.h"

#include <string>

#include "drizzled/foreign_key.h"

#include "drizzled/error.h"

#include "drizzled/create_field.h"

#include "drizzled/internal/my_sys.h"

namespace drizzled

{

extern const CHARSET_INFO *system_charset_info;

Foreign_key::Foreign_key(const Foreign_key &rhs, memory::Root *mem_root)

  :Key(rhs),

  ref_table(rhs.ref_table),

  ref_columns(rhs.ref_columns),

  delete_opt(rhs.delete_opt),

  update_opt(rhs.update_opt),

  match_opt(rhs.match_opt)

{

  list_copy_and_replace_each_value(ref_columns, mem_root);

}

/*

  Test if a foreign key (= generated key) is a prefix of the given key

  (ignoring key name, key type and order of columns)

  NOTES:

    This is only used to test if an index for a FOREIGN KEY exists

  IMPLEMENTATION

    We only compare field names

  RETURN

    0	Generated key is a prefix of other key

    1	Not equal

*/

bool foreign_key_prefix(Key *a, Key *b)

{

  /* Ensure that 'a' is the generated key */

  if (a->generated)

  {

    if (b->generated && a->columns.elements > b->columns.elements)

      std::swap(a, b);                       // Put shorter key in 'a'

  }

  else

  {

    if (!b->generated)

      return true;                              // No foreign key

    std::swap(a, b);                       // Put generated key in 'a'

  }

  /* Test if 'a' is a prefix of 'b' */

  if (a->columns.elements > b->columns.elements)

    return true;                                // Can't be prefix

  List_iterator<Key_part_spec> col_it1(a->columns);

  List_iterator<Key_part_spec> col_it2(b->columns);

  const Key_part_spec *col1, *col2;

#ifdef ENABLE_WHEN_INNODB_CAN_HANDLE_SWAPED_FOREIGN_KEY_COLUMNS

  while ((col1= col_it1++))

  {

    bool found= 0;

    col_it2.rewind();

    while ((col2= col_it2++))

    {

      if (*col1 == *col2)

      {

        found= true;

	break;

      }

    }

    if (!found)

      return true;                              // Error

  }

  return false;                                 // Is prefix

#else

  while ((col1= col_it1++))

  {

    col2= col_it2++;

    if (!(*col1 == *col2))

      return true;

  }

  return false;                                 // Is prefix

#endif

}

/*

  Check if the foreign key options are compatible with columns

  on which the FK is created.

  RETURN

    0   Key valid

    1   Key invalid

*/

bool Foreign_key::validate(List<CreateField> &table_fields)

{

  CreateField  *sql_field;

  Key_part_spec *column;

  List_iterator<Key_part_spec> cols(columns);

  List_iterator<CreateField> it(table_fields);

  while ((column= cols++))

  {

    it.rewind();

    while ((sql_field= it++) &&

           my_strcasecmp(system_charset_info,

                         column->field_name.str,

                         sql_field->field_name)) {}

    if (!sql_field)

    {

      my_error(ER_KEY_COLUMN_DOES_NOT_EXITS, MYF(0), column->field_name.str);

      return true;

    }

  }

  return false;

}

} /* namespace drizzled */