/**
* Returns list of indexes that should be dropped.
*
* @param old_table original table
* @param new_table new table
*
* @return list of indexes that should be dropped
*
* @todo Indexes that are depending on a removed field should not be added
* to drop because they are already removed.
*/
public static function get_drop_indexes($old_schema, $old_table, $new_schema, $new_table)
{
$list = array();
if ($new_table != null && $old_table != null) {
foreach (format_index::get_table_indexes($old_schema, $old_table) as $old_index) {
$new_index = dbx::get_table_index($new_schema, $new_table, $old_index['name']);
if (!format_table::contains_index($new_schema, $new_table, $old_index['name'])) {
$list[] = $old_index;
} else {
if (!format_index::equals($new_index, $old_index)) {
$list[] = $old_index;
}
}
}
}
return $list;
}
