phpbb/phpBB/includes/db/oracle.php
David M 0424200ac6 Short story: Oracle does not like sub queries that contain columns that have the same name
Long story: Expanding the implicitly defined columns to explicitly defined columns lets us determine which columns we are actually grabbing. This lets us avoid the problem of having two columns having the same name even though one is implicit and the other is explicit.

What does this mean? It means that when doing a limit on Oracle with an implicit column and a bunch of explicit columns, the explicit columns are the ones that "win".


git-svn-id: file:///svn/phpbb/trunk@6159 89ea8834-ac86-4346-8a33-228a782c2dd0
2006-07-09 05:09:37 +00:00

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PHP

<?php
/**
*
* @package dbal
* @version $Id$
* @copyright (c) 2005 phpBB Group
* @license http://opensource.org/licenses/gpl-license.php GNU Public License
*
*/
/**
*/
if (!defined('IN_PHPBB'))
{
exit;
}
/**
* @ignore
*/
if(!defined('SQL_LAYER'))
{
define('SQL_LAYER', 'oracle');
include($phpbb_root_path . 'includes/db/dbal.' . $phpEx);
/**
* Oracle Database Abstraction Layer
* @package dbal
*/
class dbal_oracle extends dbal
{
var $last_query_text = '';
/**
* Connect to server
*/
function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false)
{
$this->persistency = $persistency;
$this->user = $sqluser;
$this->server = $sqlserver . (($port) ? ':' . $port : '');
$this->dbname = $database;
$this->db_connect_id = ($this->persistency) ? @ociplogon($this->user, $sqlpassword, $this->server) : @ocinlogon($this->user, $sqlpassword, $this->server);
return ($this->db_connect_id) ? $this->db_connect_id : $this->sql_error('');
}
/**
* SQL Transaction
* @access: private
*/
function _sql_transaction($status = 'begin')
{
switch ($status)
{
case 'begin':
return true;
break;
case 'commit':
return @ocicommit($this->db_connect_id);
break;
case 'rollback':
return @ocirollback($this->db_connect_id);
break;
}
return true;
}
/**
* Base query method
*/
function sql_query($query = '', $cache_ttl = 0)
{
if ($query != '')
{
global $cache;
// EXPLAIN only in extra debug mode
if (defined('DEBUG_EXTRA'))
{
$this->sql_report('start', $query);
}
$this->last_query_text = $query;
$this->query_result = ($cache_ttl && method_exists($cache, 'sql_load')) ? $cache->sql_load($query) : false;
$this->sql_add_num_queries($this->query_result);
if (!$this->query_result)
{
$in_transaction = false;
if (!$this->transaction)
{
$this->sql_transaction('begin');
}
else
{
$in_transaction = true;
}
$this->query_result = @ociparse($this->db_connect_id, $query);
$success = @ociexecute($this->query_result, OCI_DEFAULT);
if (!$success)
{
$this->sql_error($query);
$this->query_result = false;
}
else
{
if (!$in_transaction)
{
$this->sql_transaction('commit');
}
}
if (defined('DEBUG_EXTRA'))
{
$this->sql_report('stop', $query);
}
if ($cache_ttl && method_exists($cache, 'sql_save'))
{
$this->open_queries[(int) $this->query_result] = $this->query_result;
$cache->sql_save($query, $this->query_result, $cache_ttl);
}
else if (strpos($query, 'SELECT') === 0 && $this->query_result)
{
$this->open_queries[(int) $this->query_result] = $this->query_result;
}
}
else if (defined('DEBUG_EXTRA'))
{
$this->sql_report('fromcache', $query);
}
}
else
{
return false;
}
return ($this->query_result) ? $this->query_result : false;
}
/**
* Build LIMIT query
*/
function sql_query_limit($query, $total, $offset = 0, $cache_ttl = 0)
{
if ($query != '')
{
$this->query_result = false;
// Any implicit columns exist?
if (strpos($query, '.*') !== false)
{
// This sucker does a few things for us. It grabs all the explicitly named columns and what tables are being used
preg_match('/SELECT (?:DISTINCT )?(.*?)FROM(.*?)(?:WHERE|(ORDER|GROUP) BY|$)/s', $query, $tables);
// The prefixes of the explicit columns don't matter, they simply get in the way
preg_match_all('/\.(\w+)/', trim($tables[1]), $columns);
// Flip lets us do an easy isset() call
$columns = array_flip($columns[1]);
$table_data = trim($tables[2]);
// Grab the implicitly named columns, they need expanding...
preg_match_all('/(\w)\.\*/', $query, $info);
$cols = array();
foreach ($info[1] as $table_alias)
{
// We need to get the name of the aliased table
preg_match('/(\w+) ' . $table_alias . '/', $table_data, $table_name);
$table_name = $table_name[1];
$sql = "SELECT column_name
FROM all_tab_cols
WHERE table_name = '" . strtoupper($table_name) . "'";
$result = $this->sql_query($sql);
while ($row = $this->sql_fetchrow($result))
{
if (!isset($columns[strtolower($row['column_name'])]))
{
$cols[] = $table_alias . '.' . strtolower($row['column_name']);
}
}
$this->sql_freeresult($result);
// Remove the implicity .* with it's full expansion
$query = str_replace($table_alias . '.*', implode(', ', $cols), $query);
unset($cols);
}
}
$query = 'SELECT * FROM (SELECT /*+ FIRST_ROWS */ rownum AS xrownum, a.* FROM (' . $query . ') a WHERE rownum <= ' . ($offset + $total) . ') WHERE xrownum >= ' . $offset;
return $this->sql_query($query, $cache_ttl);
}
else
{
return false;
}
}
/**
* Return number of rows
* Not used within core code
*/
function sql_numrows($query_id = false)
{
if (!$query_id)
{
$query_id = $this->query_result;
}
$result = @ocifetchstatement($query_id, $this->rowset);
// OCIFetchStatment kills our query result so we have to execute the statment again
// if we ever want to use the query_id again.
@ociexecute($query_id, OCI_DEFAULT);
return $result;
}
/**
* Return number of affected rows
*/
function sql_affectedrows()
{
return ($this->query_result) ? @ocirowcount($this->query_result) : false;
}
/**
* Fetch current row
*/
function sql_fetchrow($query_id = false)
{
global $cache;
if (!$query_id)
{
$query_id = $this->query_result;
}
if (isset($cache->sql_rowset[$query_id]))
{
return $cache->sql_fetchrow($query_id);
}
$row = array();
$result = @ocifetchinto($query_id, $row, OCI_ASSOC + OCI_RETURN_NULLS);
if (!$result || !$row)
{
return false;
}
$result_row = array();
foreach ($row as $key => $value)
{
// OCI->CLOB?
if (is_object($value))
{
$value = ($value->size()) ? $value->read($value->size()) : '';
}
$result_row[strtolower($key)] = $value;
}
return ($query_id) ? $result_row : false;
}
/**
* Fetch field
* if rownum is false, the current row is used, else it is pointing to the row (zero-based)
*/
function sql_fetchfield($field, $rownum = false, $query_id = false)
{
if (!$query_id)
{
$query_id = $this->query_result;
}
if ($query_id)
{
if ($rownum !== false)
{
$this->sql_rowseek($rownum, $query_id);
}
$row = $this->sql_fetchrow($query_id);
return isset($row[$field]) ? $row[$field] : false;
}
return false;
}
/**
* Seek to given row number
* rownum is zero-based
*/
function sql_rowseek($rownum, $query_id = false)
{
if (!$query_id)
{
$query_id = $this->query_result;
}
if (!$query_id)
{
return false;
}
// Reset internal pointer
@ociexecute($query_id, OCI_DEFAULT);
// We do not fetch the row for rownum == 0 because then the next resultset would be the second row
for ($i = 0; $i < $rownum; $i++)
{
if (!$this->sql_fetchrow($query_id))
{
return false;
}
}
return true;
}
/**
* Get last inserted id after insert statement
*/
function sql_nextid()
{
$query_id = $this->query_result;
if ($query_id && $this->last_query_text != '')
{
if (preg_match('#^INSERT[\t\n ]+INTO[\t\n ]+([a-z0-9\_\-]+)#is', $this->last_query_text, $tablename))
{
$query = 'SELECT ' . $tablename[1] . '_seq.currval FROM DUAL';
$stmt = @ociparse($this->db_connect_id, $query);
@ociexecute($stmt, OCI_DEFAULT );
$temp_result = @ocifetchinto($stmt, $temp_array, OCI_ASSOC + OCI_RETURN_NULLS);
@ocifreestatement($stmt);
if ($temp_result)
{
return $temp_array['CURRVAL'];
}
else
{
return false;
}
}
}
return false;
}
/**
* Free sql result
*/
function sql_freeresult($query_id = false)
{
if (!$query_id)
{
$query_id = $this->query_result;
}
if (isset($this->open_queries[(int) $query_id]))
{
unset($this->open_queries[(int) $query_id]);
return @ocifreestatement($query_id);
}
return false;
}
/**
* Escape string used in sql query
*/
function sql_escape($msg)
{
return str_replace("'", "''", $msg);
}
function _sql_custom_build($stage, $data)
{
return $data;
}
/**
* return sql error array
* @access: private
*/
function _sql_error()
{
$error = @ocierror();
$error = (!$error) ? @ocierror($this->query_result) : $error;
$error = (!$error) ? @ocierror($this->db_connect_id) : $error;
if ($error)
{
$this->last_error_result = $error;
}
else
{
$error = (isset($this->last_error_result) && $this->last_error_result) ? $this->last_error_result : array();
}
return $error;
}
/**
* Close sql connection
* @access: private
*/
function _sql_close()
{
return @ocilogoff($this->db_connect_id);
}
/**
* Build db-specific report
* @access: private
*/
function _sql_report($mode, $query = '')
{
switch ($mode)
{
case 'start':
break;
case 'fromcache':
$endtime = explode(' ', microtime());
$endtime = $endtime[0] + $endtime[1];
$result = @ociparse($this->db_connect_id, $query);
$success = @ociexecute($result, OCI_DEFAULT);
$row = array();
while (@ocifetchinto($result, $row, OCI_ASSOC + OCI_RETURN_NULLS))
{
// Take the time spent on parsing rows into account
}
@ocifreestatement($result);
$splittime = explode(' ', microtime());
$splittime = $splittime[0] + $splittime[1];
$this->sql_report('record_fromcache', $query, $endtime, $splittime);
break;
}
}
}
} // if ... define
?>