<?php
/**
*
* This file is part of the phpBB Forum Software package.
*
* @copyright (c) phpBB Limited <https://www.phpbb.com>
* @license GNU General Public License, version 2 (GPL-2.0)
*
* For full copyright and license information, please see
* the docs/CREDITS.txt file.
*
*/
namespace phpbb\db\driver;
/**
* Abstract MySQL Database Base Abstraction Layer
*/
abstract class mysql_base extends \phpbb\db\driver\driver
{
/**
* {@inheritDoc}
*/
public function sql_concatenate($expr1, $expr2)
{
return 'CONCAT(' . $expr1 . ', ' . $expr2 . ')';
}
/**
* Build LIMIT query
*/
function _sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
{
$this->query_result = false;
// if $total is set to 0 we do not want to limit the number of rows
if ($total == 0)
{
// MySQL 4.1+ no longer supports -1 in limit queries
$total = '18446744073709551615';
}
$query .= "\n LIMIT " . ((!empty($offset)) ? $offset . ', ' . $total : $total);
return $this->sql_query($query, $cache_ttl);
}
/**
* {@inheritDoc}
*/
function get_estimated_row_count($table_name)
{
$table_status = $this->get_table_status($table_name);
if (isset($table_status['Engine']))
{
if ($table_status['Engine'] === 'MyISAM')
{
return $table_status['Rows'];
}
else if ($table_status['Engine'] === 'InnoDB' && $table_status['Rows'] > 100000)
{
return '~' . $table_status['Rows'];
}
}
return parent::get_row_count($table_name);
}
/**
* {@inheritDoc}
*/
function get_row_count($table_name)
{
$table_status = $this->get_table_status($table_name);
if (isset($table_status['Engine']) && $table_status['Engine'] === 'MyISAM')
{
return $table_status['Rows'];
}
return parent::get_row_count($table_name);
}
/**
* Gets some information about the specified table.
*
* @param string $table_name Table name
*
* @return array
*
* @access protected
*/
function get_table_status($table_name)
{
$sql = "SHOW TABLE STATUS
LIKE '" . $this->sql_escape($table_name) . "'";
$result = $this->sql_query($sql);
$table_status = $this->sql_fetchrow($result);
$this->sql_freeresult($result);
return $table_status;
}
/**
* Build LIKE expression
* @access private
*/
function _sql_like_expression($expression)
{
return $expression;
}
/**
* Build NOT LIKE expression
* @access private
*/
function _sql_not_like_expression($expression)
{
return $expression;
}
/**
* Build db-specific query data
* @access private
*/
function _sql_custom_build($stage, $data)
{
switch ($stage)
{
case 'FROM':
$data = '(' . $data . ')';
break;
}
return $data;
}
}