<?php
// Own namespace
namespace Org\Mxchange\CoreFramework\Database\Backend;

// Import framework stuff
use Org\Mxchange\CoreFramework\Criteria\Local\LocalSearchCriteria;
use Org\Mxchange\CoreFramework\Criteria\Storing\StoreableCriteria;
use Org\Mxchange\CoreFramework\Database\FrameworkDatabase;

/**
 * An interface for front-end database classes. The classes should prepare the
 * objects for saving in the database. So for server-bases database classes SQL
 * queries shall be generated and send to the backend classes. In case of local
 * file databases the object shall be serialized and (maybe) transparently
 * compressed before they got saved to a local file.
 *
 * @author		Roland Haeder <webmaster@shipsimu.org>
 * @version		0.0.0
 * @copyright	Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2017 Core Developer Team
 * @license		GNU GPL 3.0 or any newer version
 * @link		http://www.shipsimu.org
 *
 * 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 */
interface DatabaseBackend extends FrameworkDatabase {
	/**
	 * Getter for last read file
	 *
	 * @return	$lastFile	The last read file's name with full path
	 */
	function getLastFile ();

	/**
	 * Getter for last read file's content as an array
	 *
	 * @return	$lastContent	The array with elements 'header' and 'data'.
	 */
	function getLastContents ();

	/**
	 * Getter for file extension
	 *
	 * @return	$fileExtension	The array with elements 'header' and 'data'.
	 */
	function getFileExtension ();

	/**
	 * Getter for index key
	 *
	 * @return	$indexKey	Index key
	 */
	function getIndexKey ();

	/**
	 * Makes sure that the database connection is alive
	 *
	 * @return	void
	 * @todo	Do some checks on the database directory and files here
	 */
	function connectToDatabase ();

	/**
	 * Starts a SELECT query on the database by given return type, table name
	 * and search criteria
	 *
	 * @param	$tableName			Name of the database table
	 * @param	$searchInstance		Local search criteria class
	 * @return	$resultData			Result data of the query
	 * @throws	UnsupportedCriteriaException	If the criteria is unsupported
	 * @throws	SqlException					If an 'SQL error' occurs
	 */
	function querySelect ($tableName, LocalSearchCriteria $searchInstance);

	/**
	 * "Inserts" a data set instance into a local file database folder
	 *
	 * @param	$dataSetInstance	A storeable data set
	 * @return	void
	 * @throws	SqlException	If an SQL error occurs
	 */
	function queryInsertDataSet (StoreableCriteria $dataSetInstance);

	/**
	 * "Updates" a data set instance with a database layer
	 *
	 * @param	$dataSetInstance	A storeable data set
	 * @return	void
	 * @throws	SqlException	If an SQL error occurs
	 */
	function queryUpdateDataSet (StoreableCriteria $dataSetInstance);

	/**
	 * Getter for primary key of specified table or if not found null will be
	 * returned. This must be database-specific.
	 *
	 * @param	$tableName		Name of the table we need the primary key from
	 * @return	$primaryKey		Primary key column of the given table
	 */
	function getPrimaryKeyOfTable ($tableName);

	/**
	 * Removes non-data from given array.
	 *
	 * @param	$data	An array with possible non-data that needs to be removed.
	 * @return	$data	A cleaned up array with only data.
	 * @todo	Add more generic non-data for removal
	 */
	function removeNonPublicDataFromArray (array $data);

	/**
	 * Counts total rows of given table
	 *
	 * @param	$tableName	Table name
	 * @return	$count		Total rows of given table
	 */
	function countTotalRows($tableName);

}