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Path: /data/applications/aps/gallery/2.2-08/htdocs/modules/core/classes/GalleryStorage/ [ Home ]
File: Db2Storage.class
<?php
/*
 * Gallery - a web based photo album viewer and editor
 * Copyright (C) 2000-2007 Bharat Mediratta
 *
 * 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 2 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
 */

GalleryCoreApi::requireOnce('modules/core/classes/GalleryStorage.class');

/**
 * IBM DB2 UDB (for Linux/UNIX/Windows) extension of the GalleryStorage class.
 * This object implements the hooks for saving and restoring objects in an
 * IBM DB2 Universal Database database.
 *
 * @package GalleryCore
 * @subpackage Storage
 * @version $Revision: 15874 $
 */
class Db2Storage extends GalleryStorage {

    function Db2Storage($config) {
	$this->GalleryStorage($config);
	$this->_isTransactional = true;
    }

    /**
     * Return the type of this database
     * @return string
     */
    function getType() {
	return 'db2';
    }

    /**
     * @see GalleryStorage::cleanStore
     */
    function cleanStore() {
	$ret = parent::cleanStore();
	if ($ret) {
	    return $ret;
	}

	/* Create a temporary database connection and install our custom aggregate function */
	list ($ret, $tmpDb) = $this->_getConnection(true);
	if ($ret) {
	    return $ret;
	}

	$statements = array();
	$statements[] = 'DROP FUNCTION G2_BIT_AND(CHAR(32), CHAR(32))';
	$statements[] = 'DROP FUNCTION BIT_AND(SMALLINT, SMALLINT)';
	$statements[] = 'DROP FUNCTION G2_LIKE(VARCHAR(8000), VARCHAR(8000))';
	$statements[] = 'DROP FUNCTION G2_BIT_OR(INTEGER, VARCHAR(32))';
	/*
	 * Unregister the Jar file; use ODBC delimiters, see
	 * http://gallery.menalto.com/node/37648?from=850#comment-172690
	 */
	$statements[] = "{CALL SQLJ.REMOVE_JAR('g2_db2_jar')}";
	foreach ($statements as $sql) {
	    $this->_traceStart();
	    $recordSet = $tmpDb->Execute($sql);
	    $this->_traceStop();
	    if (empty($recordSet)) {
		return GalleryCoreApi::error(ERROR_STORAGE_FAILURE);
	    }
	}
	$tmpDb->Close();

	return null;
    }

    /**
     * @see GalleryStorage::configureStore
     */
    function configureStore($moduleId, $upgradeInfo=array()) {
	if ($moduleId == 'core') {
	    global $gallery;

	    /*
	     *  Create our user-defined DB2 functions
	     *   1) Create a temporary database connection
	     *   2) Register the Jar file
	     *   3) Create/Catalog the UDFs
	     *   4) Disconnect from the database
	     */
	    $platform =& $gallery->getPlatform();
	    $slash = $platform->getDirectorySeparator();

	    /* 1) Create a temporary database connection */
	    list ($ret, $tmpDb) = $this->_getConnection(true);
	    if ($ret) {
		return $ret;
	    }

	    /*
	     * 2) Register the Jar file (use ODBC delimiters, see
	     *    http://gallery.menalto.com/node/37648?from=850#comment-172690)
	     */
	    $sql = "{CALL SQLJ.INSTALL_JAR('file:" . dirname(__FILE__) . $slash .
		    "g2_db2.jar',  'g2_db2_jar')}";
	    $this->_traceStart();
	    $recordSet = $tmpDb->Execute($sql);
	    $this->_traceStop();
	    if (empty($recordSet)) {
		/*
		 * XXX: At some point figure out a way to detect if the UDFs are
		 * already there before trying to install them again.
		 */
		if ($gallery->getDebug()) {
		    $gallery->debug('Failed to install g2_db2.jar .. continuing ' .
				    'under the assumption that this is an upgrade');
		}
	    } else {
		/* 3) Create/Catalog the UDFs */
		$ret = $this->_executeSqlFile(dirname(__FILE__) . $slash . 'Db2CreateUdfs.sql');
		if ($ret) {
		    return $ret;
		}
	    }

	    /* 4) Disconnect from the database */
	    $tmpDb->Close();

	}

	$ret = parent::configureStore($moduleId, $upgradeInfo);
	if ($ret) {
	    return $ret;
	}

	return null;
     }

    /**
     * @see GalleryStorage::convertIntToBits
     */
    function convertIntToBits($intVal) {
	return sprintf("%032b", $intVal);
    }

    /**
     * @see GalleryStorage::convertBitsToInt
     */
    function convertBitsToInt($bitsVal) {
	return bindec($bitsVal);
    }

    /**
     * @see GalleryStorage::getFunctionsSql
     */
    function getFunctionSql($functionName, $args) {
	switch($functionName) {
	case 'CONCAT':
	    /*
	     * CHAR($value) creates a string of length 11 for large and a string of length 4 for
	     * smaller integer values. Thus we need to trim the string to the actual length of the
	     * string representation of the integer
	     */
	    foreach ($args as $key => $value) {
		$args[$key] = 'RTRIM(CHAR(' . $value . '))';
	    }
	    $sql = implode(' || ', $args);
	    break;

	case 'BITAND':
	    $sql = 'G2_BIT_AND (CAST(' . $args[0] . ' AS CHAR(32)), ' .
		'CAST(' . $args[1] . ' AS CHAR(32)))';
	    break;

	case 'BIT_OR':
	    /*
	     * Emulation of a user-defined aggregate function by using a UDF that always operates
	     * on 2 operands (last result from scratchpad and current row) and outputs the result,
	     * plus it stores the result in the DB2 scratchpad. We use the built-in aggregate
	     * function MAX() to select the last "intermediate" result of the BIT_OR
	     */

	    /*
	     * arg 0 is the column over which we do the BIT_OR, arg 1 is the GROUP BY column
	     * (or a constant number if no GROUP BY clause is used)
	     */
	    $sql = 'MAX(G2_BIT_OR (' . $args[1] . ', ' . $args[0] . '))';
	    break;

	case 'UNIX_TIMESTAMP':
	    $sql = 'date_part(\'epoch\', ' . $args[0] . ')';
	    break;

	case 'AS':
	    $sql = 'AS';
	    break;

	case 'SUBSTRING':
	    $sql = sprintf('SUBSTR(%s)', implode(', ', $args));
	    break;

	case 'RAND':
	    /* Add random parameter to seed DB2 random number generator */
	    $sql = sprintf('RAND(%s)', empty($args) ? mt_rand(0, 2147483647) : $args[0]);
	    break;

	case 'LIMIT':
	    $sql = $args[1] . ' FETCH FIRST ' . $args[0] . ' ROWS ONLY';
	    break;

	case 'CASE':
	    $sql = array();
	    while (count($args) > 1) {
		$sql[] = 'WHEN ' . array_shift($args) . ' THEN ' . array_shift($args);
	    }
	    $sql = 'CASE ' . implode(' ', $sql) . ' ELSE ' . $args[0] . ' END';
	    break;

	case 'LIKE':
	    /* DB2's LIKE predicate support is very restrictive.  No non-strings, no SQL UDFs. */
	    $sql = 'G2_LIKE(' . $args[0] . ', ' . $args[1] . ') = 1';
	    break;

	case 'MULTI_INSERT':
	    /*
	     * 0 - table name
	     * 1 - array of column names
	     * 2 - number of rows
	     */
	    $markers = GalleryUtilities::makeMarkers(sizeof($args[1]));
	    $rowList = rtrim(str_repeat('(' . $markers . '), ', $args[2]), ', ');
	    $sql = 'INSERT INTO ' . $args[0] . ' (';
	    $sql .= join(', ', $args[1]);
	    $sql .= ') VALUES ' . $rowList;
	    break;

	case 'AVG':
	    /*
	     * DB2's AVG's return value is of the same type as the input value. To get the same
	     * behavior that we expect from MySQL and PostgreSQL, cast the input to double
	     */
	    $sql = sprintf('AVG(double(%s))', $args[0]);
	    break;

	default:
	    return array(GalleryCoreApi::error(ERROR_UNIMPLEMENTED, __FILE__, __LINE__,
					      $functionName . ' ' . implode(' ', $args)), null);
	}

	return array(null, $sql);
    }

    /**
     * Get database version.
     * @return string version
     */
    function getVersion() {
	global $gallery;
	$platform =& $gallery->getPlatform();

	list ($success, $results) = $platform->exec(array(array('db2level')));
	if ($success && is_array($results)) {
	    return implode("\n", $results);
	} else {
	    return '';
	}
    }

    /**
     * @see GalleryStorage::_getOptimizeStatements
     */
    function _getOptimizeStatements() {
	return array('CALL ADMIN_CMD (\'REORG TABLE ' . $this->_username . '.%s\')',
		     'CALL ADMIN_CMD (\'RUNSTATS ON TABLE ' . $this->_username .
		     '.%s WITH DISTRIBUTION ON ALL COLUMNS AND INDEXES ALL\')');

    }

    /**
     * Truncate UTF-8 strings to given byte length rather than character length since DB2 interprets
     * string lengths in bytes.
     * @see GalleryStorage::_truncateString
     */
    function _truncateString($value, $size, $lengthInBytes=false) {
	return parent::_truncateString($value, $size, true);
    }

    /**
     * @see GalleryStorage::encodeBlob
     */
    function encodeBlob($blob) {
	return addcslashes($blob, "\000\134\377");
    }

    /**
     * @see GalleryStorage::decodeBlob
     */
    function decodeBlob($blob) {
	return stripcslashes($blob);
    }
}
?>