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<?php
/* vim: set expandtab tabstop=4 shiftwidth=4 softtabstop=4: */

/**
 * Contains the DB_QueryTool_EasyJoin class
 *
 * PHP versions 4 and 5
 *
 * LICENSE: This source file is subject to version 3.0 of the PHP license
 * that is available through the world-wide-web at the following URI:
 * http://www.php.net/license/3_0.txt.  If you did not receive a copy of
 * the PHP License and are unable to obtain it through the web, please
 * send a note to license@php.net so we can mail you a copy immediately.
 *
 * @category   Database
 * @package    DB_QueryTool
 * @author     Wolfram Kriesing <wk@visionp.de>
 * @author     Paolo Panto <wk@visionp.de>
 * @copyright  2003-2005 Wolfram Kriesing, Paolo Panto
 * @license    http://www.php.net/license/3_0.txt  PHP License 3.0
 * @version    CVS: $Id: EasyJoin.php,v 1.9 2005/02/27 17:15:05 quipo Exp $
 * @link       http://pear.php.net/package/DB_QueryTool
 */

/**
 * require the DB_QueryTool_Query class
 */
require_once 'DB/QueryTool/Query.php';

/**
 * DB_QueryTool_EasyJoin class
 *
 * @category   Database
 * @package    DB_QueryTool
 * @author     Wolfram Kriesing <wk@visionp.de>
 * @copyright  2003-2005 Wolfram Kriesing
 * @license    http://www.php.net/license/3_0.txt  PHP License 3.0
 * @link       http://pear.php.net/package/DB_QueryTool
 */
class DB_QueryTool_EasyJoin extends DB_QueryTool_Query
{
    // {{{ class vars

    /**
     * This is the regular expression that shall be used to find a table's shortName
     * in a column name, the string found by using this regular expression will be removed
     * from the column name and it will be checked if it is a table name
     * i.e. the default '/_id$/' would find the table name 'user' from the column name 'user_id'
     *
     * @var string regexp
     */
    var $_tableNamePreg = '/_id$/';

    /**
     * This is to find the column name that is referred by it, so the default find
     * from 'user_id' the column 'id' which will be used to refer to the 'user' table
     *
     * @var string regexp
     */
    var $_columnNamePreg = '/^.*_/';

    // }}}
    // {{{ __construct()

    /**
     * call parent constructor
     * @param mixed $dsn DSN string, DSN array or DB object
     * @param array $options
     */
    function __construct($dsn=false, $options=array())
    {
        parent::DB_QueryTool_Query($dsn, $options);
    }

    // }}}
    // {{{ autoJoin()

    /**
     * Join the given tables, using the column names, to find out how to join the tables;
     * i.e., if table1 has a column named &quot;table2_id&quot;, this method will join
     * &quot;WHERE table1.table2_id=table2.id&quot;.
     * All joins made here are only concatenated via AND.
     * @param array $tables
     */
    function autoJoin($tables)
    {
// FIXXME if $tables is empty autoJoin all available tables that have a relation
// to $this->table, starting to search in $this->table
        settype($tables, 'array');
        // add this->table to the tables array, so we go thru the current table first
        $tables = array_merge(array($this->table), $tables);

        $shortNameIndexed = $this->getTableSpec(true, $tables);
        $nameIndexed = $this->getTableSpec(false, $tables);

//print_r($shortNameIndexed);
//print_r($tables);        print '<br><br>';
        if (sizeof($shortNameIndexed) != sizeof($tables)) {
            $this->_errorLog("autoJoin-ERROR: not all the tables are in the tableSpec!<br />");
        }

        $joinTables = array();
        $joinConditions = array();
        foreach ($tables as $aTable) {   // go through $this->table and all the given tables
            if ($metadata = $this->metadata($aTable))
            foreach ($metadata as $aCol => $x) {   // go through each row to check which might be related to $aTable
                $possibleTableShortName = preg_replace($this->_tableNamePreg,  '' , $aCol);
                $possibleColumnName     = preg_replace($this->_columnNamePreg, '' , $aCol);
//print "$aTable.$aCol .... possibleTableShortName=$possibleTableShortName .... possibleColumnName=$possibleColumnName<br />";
                if (isset($shortNameIndexed[$possibleTableShortName])) {
                    // are the tables given in the tableSpec?
                    if (!$shortNameIndexed[$possibleTableShortName]['name'] ||
                        !$nameIndexed[$aTable]['name']) {
                        // its an error of the developer, so log the error, dont show it to the end user
                        $this->_errorLog("autoJoin-ERROR: '$aTable' is not given in the tableSpec!<br />");
                    } else {
                        // do only join different table.col combination,
                        // we should not join stuff like 'question.question=question.question'
                        // this would be quite stupid, but it used to be :-(
                        if ($shortNameIndexed[$possibleTableShortName]['name'] != $aTable ||
                            $possibleColumnName != $aCol
                        ) {
                            $where = $shortNameIndexed[$possibleTableShortName]['name'].".$possibleColumnName=$aTable.$aCol";
                            $this->addJoin($nameIndexed[$aTable]['name'],                      $where);
                            $this->addJoin($shortNameIndexed[$possibleTableShortName]['name'], $where);
                        }
                    }
                }
            }
        }
    }

    // }}}
}
?>