/**
* Reset all database tables to default values.
* @static
* @return bool true if reset done, false if skipped
*/
public static function reset_database() {
global $DB;
if (!is_null(self::$lastdbwrites) and self::$lastdbwrites == $DB->perf_get_writes()) {
return false;
}
$tables = $DB->get_tables(false);
if (!$tables or empty($tables['config'])) {
// not installed yet
return false;
}
if (!$data = self::get_tabledata()) {
// not initialised yet
return false;
}
if (!$structure = self::get_tablestructure()) {
// not initialised yet
return false;
}
$empties = self::guess_unmodified_empty_tables();
foreach ($data as $table => $records) {
if (empty($records)) {
if (isset($empties[$table])) {
// table was not modified and is empty
} else {
$DB->delete_records($table, array());
}
continue;
}
if (isset($structure[$table]['id']) and $structure[$table]['id']->auto_increment) {
$currentrecords = $DB->get_records($table, array(), 'id ASC');
$changed = false;
foreach ($records as $id => $record) {
if (!isset($currentrecords[$id])) {
$changed = true;
break;
}
if ((array)$record != (array)$currentrecords[$id]) {
$changed = true;
break;
}
unset($currentrecords[$id]);
}
if (!$changed) {
if ($currentrecords) {
$lastrecord = end($records);
$DB->delete_records_select($table, "id > ?", array($lastrecord->id));
continue;
} else {
continue;
}
}
}
$DB->delete_records($table, array());
foreach ($records as $record) {
$DB->import_record($table, $record, false, true);
}
}
// reset all next record ids - aka sequences
self::reset_all_database_sequences($empties);
// remove extra tables
foreach ($tables as $table) {
if (!isset($data[$table])) {
$DB->get_manager()->drop_table(new xmldb_table($table));
}
}
self::$lastdbwrites = $DB->perf_get_writes();
return true;
}
