/**
* Retrieve all the versions that have been migrated.
*
* @return array
*/
private function _getAllMigratedVersions()
{
// In Rails:
// table = Arel::Table.new(schema_migrations_table_name)
// Base.connection.select_values(table.project(table['version']).to_sql).map(&:to_i).sort
$col = $this->_db->fetchCol("SELECT version FROM " . $this->_getMigrationTableName());
return $col;
}
