MDL-33399 files: Fixed up handling of empty sort in File API methods.

[moodle.git] / lib / db / upgrade.php

<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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.
//
// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**
 * This file keeps track of upgrades to Moodle.
 *
 * Sometimes, changes between versions involve
 * alterations to database structures and other
 * major things that may break installations.
 *
 * The upgrade function in this file will attempt
 * to perform all the necessary actions to upgrade
 * your older installation to the current version.
 *
 * If there's something it cannot do itself, it
 * will tell you what you need to do.
 *
 * The commands in here will all be database-neutral,
 * using the methods of database_manager class
 *
 * Please do not forget to use upgrade_set_timeout()
 * before any action that may take longer time to finish.
 *
 * @package   core_install
 * @category  upgrade
 * @copyright 2006 onwards Martin Dougiamas  http://dougiamas.com
 * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
 */

defined('MOODLE_INTERNAL') || die();

/**
 * Main upgrade tasks to be executed on Moodle version bump
 *
 * This function is automatically executed after one bump in the Moodle core
 * version is detected. It's in charge of performing the required tasks
 * to raise core from the previous version to the next one.
 *
 * It's a collection of ordered blocks of code, named "upgrade steps",
 * each one performing one isolated (from the rest of steps) task. Usually
 * tasks involve creating new DB objects or performing manipulation of the
 * information for cleanup/fixup purposes.
 *
 * Each upgrade step has a fixed structure, that can be summarised as follows:
 *
 * if ($oldversion < XXXXXXXXXX.XX) {
 *     // Explanation of the update step, linking to issue in the Tracker if necessary
 *     upgrade_set_timeout(XX); // Optional for big tasks
 *     // Code to execute goes here, usually the XMLDB Editor will
 *     // help you here. See {@link http://docs.moodle.org/dev/XMLDB_editor}.
 *     upgrade_main_savepoint(true, XXXXXXXXXX.XX);
 * }
 *
 * All plugins within Moodle (modules, blocks, reports...) support the existence of
 * their own upgrade.php file, using the "Frankenstyle" component name as
 * defined at {@link http://docs.moodle.org/dev/Frankenstyle}, for example:
 *     - {@link xmldb_page_upgrade($oldversion)}. (modules don't require the plugintype ("mod_") to be used.
 *     - {@link xmldb_auth_manual_upgrade($oldversion)}.
 *     - {@link xmldb_workshopform_accumulative_upgrade($oldversion)}.
 *     - ....
 *
 * In order to keep the contents of this file reduced, it's allowed to create some helper
 * functions to be used here in the {@link upgradelib.php} file at the same directory. Note
 * that such a file must be manually included from upgrade.php, and there are some restrictions
 * about what can be used within it.
 *
 * For more information, take a look to the documentation available:
 *     - Data definition API: {@link http://docs.moodle.org/dev/Data_definition_API}
 *     - Upgrade API: {@link http://docs.moodle.org/dev/Upgrade_API}
 *
 * @param int $oldversion
 * @return bool always true
 */
function xmldb_main_upgrade($oldversion) {
    global $CFG, $USER, $DB, $OUTPUT;

    require_once($CFG->libdir.'/db/upgradelib.php'); // Core Upgrade-related functions

    $dbman = $DB->get_manager(); // loads ddl manager and xmldb classes

    if ($oldversion < 2011120500) {
        // just in case somebody hacks upgrade scripts or env, we really can not continue
        echo("You need to upgrade to 2.2.x first!\n");
        exit(1);
        // Note this savepoint is 100% unreachable, but needed to pass the upgrade checks
        upgrade_main_savepoint(true, 2011120500);
    }

    // Moodle v2.2.0 release upgrade line
    // Put any upgrade step following this

    if ($oldversion < 2011120500.02) {

        upgrade_set_timeout(60*20); // This may take a while
        // MDL-28180. Some missing restrictions in certain backup & restore operations
        // were causing incorrect duplicates in the course_completion_aggr_methd table.
        // This upgrade step takes rid of them.
        $sql = 'SELECT course, criteriatype, MIN(id) AS minid
                  FROM {course_completion_aggr_methd}
              GROUP BY course, criteriatype
                HAVING COUNT(*) > 1';
        $duprs = $DB->get_recordset_sql($sql);
        foreach ($duprs as $duprec) {
            // We need to handle NULLs in criteriatype diferently
            if (is_null($duprec->criteriatype)) {
                $where = 'course = ? AND criteriatype IS NULL AND id > ?';
                $params = array($duprec->course, $duprec->minid);
            } else {
                $where = 'course = ? AND criteriatype = ? AND id > ?';
                $params = array($duprec->course, $duprec->criteriatype, $duprec->minid);
            }
            $DB->delete_records_select('course_completion_aggr_methd', $where, $params);
        }
        $duprs->close();

        // Main savepoint reached
        upgrade_main_savepoint(true, 2011120500.02);
    }

    if ($oldversion < 2011120500.03) {

        // Changing precision of field value on table user_preferences to (1333)
        $table = new xmldb_table('user_preferences');
        $field = new xmldb_field('value', XMLDB_TYPE_CHAR, '1333', null, XMLDB_NOTNULL, null, null, 'name');

        // Launch change of precision for field value
        $dbman->change_field_precision($table, $field);

        // Main savepoint reached
        upgrade_main_savepoint(true, 2011120500.03);
    }

    if ($oldversion < 2012020200.03) {

        // Define index rolecontext (not unique) to be added to role_assignments
        $table = new xmldb_table('role_assignments');
        $index = new xmldb_index('rolecontext', XMLDB_INDEX_NOTUNIQUE, array('roleid', 'contextid'));

        // Conditionally launch add index rolecontext
        if (!$dbman->index_exists($table, $index)) {
            $dbman->add_index($table, $index);
        }

        // Define index usercontextrole (not unique) to be added to role_assignments
        $index = new xmldb_index('usercontextrole', XMLDB_INDEX_NOTUNIQUE, array('userid', 'contextid', 'roleid'));

        // Conditionally launch add index usercontextrole
        if (!$dbman->index_exists($table, $index)) {
            $dbman->add_index($table, $index);
        }

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012020200.03);
    }

    if ($oldversion < 2012020200.06) {
        // Previously we always allowed users to override their email address via the messaging system
        // We have now added a setting to allow admins to turn this this ability on and off
        // While this setting defaults to 0 (off) we're setting it to 1 (on) to maintain the behaviour for upgrading sites
        set_config('messagingallowemailoverride', 1);

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012020200.06);
    }

    if ($oldversion < 2012021700.01) {
        // Changing precision of field uniquehash on table post to 255
        $table = new xmldb_table('post');
        $field = new xmldb_field('uniquehash', XMLDB_TYPE_CHAR, '255', null, XMLDB_NOTNULL, null, null, 'content');

        // Launch change of precision for field uniquehash
        $dbman->change_field_precision($table, $field);

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012021700.01);
    }

    if ($oldversion < 2012021700.02) {
        // Somewhere before 1.9 summary and content column in post table were not null. In 1.9+
        // not null became false.
        $columns = $DB->get_columns('post');

        // Fix discrepancies in summary field after upgrade from 1.9
        if (array_key_exists('summary', $columns) && $columns['summary']->not_null != false) {
            $table = new xmldb_table('post');
            $summaryfield = new xmldb_field('summary', XMLDB_TYPE_TEXT, 'big', null, null, null, null, 'subject');

            if ($dbman->field_exists($table, $summaryfield)) {
                $dbman->change_field_notnull($table, $summaryfield);
            }

        }

        // Fix discrepancies in content field after upgrade from 1.9
        if (array_key_exists('content', $columns) && $columns['content']->not_null != false) {
            $table = new xmldb_table('post');
            $contentfield = new xmldb_field('content', XMLDB_TYPE_TEXT, 'big', null, null, null, null, 'summary');

            if ($dbman->field_exists($table, $contentfield)) {
                $dbman->change_field_notnull($table, $contentfield);
            }

        }

        upgrade_main_savepoint(true, 2012021700.02);
    }

    // The ability to backup user (private) files is out completely - MDL-29248
    if ($oldversion < 2012030100.01) {
        unset_config('backup_general_user_files', 'backup');
        unset_config('backup_general_user_files_locked', 'backup');
        unset_config('backup_auto_user_files', 'backup');

        upgrade_main_savepoint(true, 2012030100.01);
    }

    if ($oldversion < 2012030100.02) {
        // migrate all numbers to signed - it should be safe to interrupt this and continue later
        upgrade_mysql_fix_unsigned_columns();

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012030100.02);
    }

    if ($oldversion < 2012030900.01) {
        // migrate all texts and binaries to big size - it should be safe to interrupt this and continue later
        upgrade_mysql_fix_lob_columns();

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012030900.01);
    }

    if ($oldversion < 2012031500.01) {
        // Upgrade old course_allowed_modules data to be permission overrides.
        if ($CFG->restrictmodulesfor === 'all') {
            $courses = $DB->get_records_menu('course', array(), 'id', 'id, 1');
        } else if ($CFG->restrictmodulesfor === 'requested') {
            $courses = $DB->get_records_menu('course', array('retrictmodules' => 1), 'id', 'id, 1');
        } else {
            $courses = array();
        }

        if (!$dbman->table_exists('course_allowed_modules')) {
            // Upgrade must already have been run on this server. This might happen,
            // for example, during development of these changes.
            $courses = array();
        }

        $modidtoname = $DB->get_records_menu('modules', array(), 'id', 'id, name');

        $coursecount = count($courses);
        if ($coursecount) {
            $pbar = new progress_bar('allowedmods', 500, true);
            $transaction = $DB->start_delegated_transaction();
        }

        $i = 0;
        foreach ($courses as $courseid => $notused) {
            $i += 1;
            upgrade_set_timeout(60); // 1 minute per course should be fine.

            $allowedmoduleids = $DB->get_records_menu('course_allowed_modules',
            array('course' => $courseid), 'module', 'module, 1');
            if (empty($allowedmoduleids)) {
                // This seems to be the best match for backwards compatibility,
                // not necessarily with the old code in course_allowed_module function,
                // but with the code that used to be in the coures settings form.
                $allowedmoduleids = explode(',', $CFG->defaultallowedmodules);
                $allowedmoduleids = array_combine($allowedmoduleids, $allowedmoduleids);
            }

            $context = context_course::instance($courseid);

            list($roleids) = get_roles_with_cap_in_context($context, 'moodle/course:manageactivities');
            list($managerroleids) = get_roles_with_cap_in_context($context, 'moodle/site:config');
            foreach ($managerroleids as $roleid) {
                unset($roleids[$roleid]);
            }

            foreach ($modidtoname as $modid => $modname) {
                if (isset($allowedmoduleids[$modid])) {
                    // Module is allowed, no worries.
                    continue;
                }

                $capability = 'mod/' . $modname . ':addinstance';
                foreach ($roleids as $roleid) {
                    assign_capability($capability, CAP_PREVENT, $roleid, $context);
                }
            }

            $pbar->update($i, $coursecount, "Upgrading legacy course_allowed_modules data - $i/$coursecount.");
        }

        if ($coursecount) {
            $transaction->allow_commit();
        }

        upgrade_main_savepoint(true, 2012031500.01);
    }

    if ($oldversion < 2012031500.02) {

        // Define field retrictmodules to be dropped from course
        $table = new xmldb_table('course');
        $field = new xmldb_field('restrictmodules');

        // Conditionally launch drop field requested
        if ($dbman->field_exists($table, $field)) {
            $dbman->drop_field($table, $field);
        }

        upgrade_main_savepoint(true, 2012031500.02);
    }

    if ($oldversion < 2012031500.03) {

        // Define table course_allowed_modules to be dropped
        $table = new xmldb_table('course_allowed_modules');

        // Conditionally launch drop table for course_allowed_modules
        if ($dbman->table_exists($table)) {
            $dbman->drop_table($table);
        }

        upgrade_main_savepoint(true, 2012031500.03);
    }

    if ($oldversion < 2012031500.04) {
        // Clean up the old admin settings.
        unset_config('restrictmodulesfor');
        unset_config('restrictbydefault');
        unset_config('defaultallowedmodules');

        upgrade_main_savepoint(true, 2012031500.04);
    }

    if ($oldversion < 2012032300.02) {
        // Migrate the old admin debug setting.
        if ($CFG->debug == 38911) {
            set_config('debug', DEBUG_DEVELOPER);
        } else if ($CFG->debug == 6143) {
            set_config('debug', DEBUG_ALL);
        }
        upgrade_main_savepoint(true, 2012032300.02);
    }

    if ($oldversion < 2012042300.00) {
        // This change makes the course_section index unique.

        // xmldb does not allow changing index uniqueness - instead we must drop
        // index then add it again
        $table = new xmldb_table('course_sections');
        $index = new xmldb_index('course_section', XMLDB_INDEX_NOTUNIQUE, array('course', 'section'));

        // Conditionally launch drop index course_section
        if ($dbman->index_exists($table, $index)) {
            $dbman->drop_index($table, $index);
        }

        // Look for any duplicate course_sections entries. There should not be
        // any but on some busy systems we found a few, maybe due to previous
        // bugs.
        $transaction = $DB->start_delegated_transaction();
        $rs = $DB->get_recordset_sql('
                SELECT DISTINCT
                    cs.id, cs.course
                FROM
                    {course_sections} cs
                    INNER JOIN {course_sections} older
                        ON cs.course = older.course AND cs.section = older.section
                        AND older.id < cs.id');
        foreach ($rs as $rec) {
            $DB->delete_records('course_sections', array('id' => $rec->id));
            rebuild_course_cache($rec->course, true);
        }
        $rs->close();
        $transaction->allow_commit();

        // Define index course_section (unique) to be added to course_sections
        $index = new xmldb_index('course_section', XMLDB_INDEX_UNIQUE, array('course', 'section'));

        // Conditionally launch add index course_section
        if (!$dbman->index_exists($table, $index)) {
            $dbman->add_index($table, $index);
        }

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012042300.00);
    }

    if ($oldversion < 2012042300.02) {
        require_once($CFG->libdir . '/completion/completion_criteria.php');
        // Delete orphaned criteria which were left when modules were removed
        if ($DB->get_dbfamily() === 'mysql') {
            $sql = "DELETE cc FROM {course_completion_criteria} cc
                    LEFT JOIN {course_modules} cm ON cm.id = cc.moduleinstance
                    WHERE cm.id IS NULL AND cc.criteriatype = ".COMPLETION_CRITERIA_TYPE_ACTIVITY;
        } else {
            $sql = "DELETE FROM {course_completion_criteria}
                    WHERE NOT EXISTS (
                        SELECT 'x' FROM {course_modules}
                        WHERE {course_modules}.id = {course_completion_criteria}.moduleinstance)
                    AND {course_completion_criteria}.criteriatype = ".COMPLETION_CRITERIA_TYPE_ACTIVITY;
        }
        $DB->execute($sql);

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012042300.02);
    }

    if ($oldversion < 2012050300.01) {
        // Make sure deleted users do not have picture flag.
        $DB->set_field('user', 'picture', 0, array('deleted'=>1, 'picture'=>1));
        upgrade_main_savepoint(true, 2012050300.01);
    }

    if ($oldversion < 2012050300.02) {

        // Changing precision of field picture on table user to (10)
        $table = new xmldb_table('user');
        $field = new xmldb_field('picture', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, '0', 'secret');

        // Launch change of precision for field picture
        $dbman->change_field_precision($table, $field);

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012050300.02);
    }

    if ($oldversion < 2012050300.03) {

        // Define field coursedisplay to be added to course
        $table = new xmldb_table('course');
        $field = new xmldb_field('coursedisplay', XMLDB_TYPE_INTEGER, '2', null, XMLDB_NOTNULL, null, '0', 'completionnotify');

        // Conditionally launch add field coursedisplay
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012050300.03);
    }

    if ($oldversion < 2012050300.04) {

        // Define table course_display to be dropped
        $table = new xmldb_table('course_display');

        // Conditionally launch drop table for course_display
        if ($dbman->table_exists($table)) {
            $dbman->drop_table($table);
        }

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012050300.04);
    }

    if ($oldversion < 2012050300.05) {

        // Clean up removed admin setting.
        unset_config('navlinkcoursesections');

        upgrade_main_savepoint(true, 2012050300.05);
    }

    if ($oldversion < 2012050400.01) {

        // Define index sortorder (not unique) to be added to course
        $table = new xmldb_table('course');
        $index = new xmldb_index('sortorder', XMLDB_INDEX_NOTUNIQUE, array('sortorder'));

        // Conditionally launch add index sortorder
        if (!$dbman->index_exists($table, $index)) {
            $dbman->add_index($table, $index);
        }

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012050400.01);
    }

    if ($oldversion < 2012050400.02) {

        // Clean up removed admin setting.
        unset_config('enablecourseajax');

        upgrade_main_savepoint(true, 2012050400.02);
    }

    if ($oldversion < 2012051100.01) {

        // Define field idnumber to be added to groups
        $table = new xmldb_table('groups');
        $field = new xmldb_field('idnumber', XMLDB_TYPE_CHAR, '100', null, XMLDB_NOTNULL, null, null, 'courseid');
        $index = new xmldb_index('idnumber', XMLDB_INDEX_NOTUNIQUE, array('idnumber'));

        // Conditionally launch add field idnumber
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }

        // Conditionally launch add index idnumber
        if (!$dbman->index_exists($table, $index)) {
            $dbman->add_index($table, $index);
        }

        // Define field idnumber to be added to groupings
        $table = new xmldb_table('groupings');
        $field = new xmldb_field('idnumber', XMLDB_TYPE_CHAR, '100', null, XMLDB_NOTNULL, null, null, 'name');
        $index = new xmldb_index('idnumber', XMLDB_INDEX_NOTUNIQUE, array('idnumber'));

        // Conditionally launch add field idnumber
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }

        // Conditionally launch add index idnumber
        if (!$dbman->index_exists($table, $index)) {
            $dbman->add_index($table, $index);
        }

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012051100.01);
    }

    if ($oldversion < 2012051100.03) {

        // Amend course table to add sectioncache cache
        $table = new xmldb_table('course');
        $field = new xmldb_field('sectioncache', XMLDB_TYPE_TEXT, null, null, null, null, null, 'showgrades');
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }

        // Amend course_sections to add date, time and groupingid availability
        // conditions and a setting about whether to show them
        $table = new xmldb_table('course_sections');
        $field = new xmldb_field('availablefrom', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, '0', 'visible');
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }
        $field = new xmldb_field('availableuntil', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, '0', 'availablefrom');
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }
        $field = new xmldb_field('showavailability', XMLDB_TYPE_INTEGER, '1', null, XMLDB_NOTNULL, null, '0', 'availableuntil');
        // Conditionally launch add field showavailability
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }
        $field = new xmldb_field('groupingid', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, '0', 'showavailability');
        // Conditionally launch add field groupingid
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }

        // Add course_sections_availability to add completion & grade availability conditions
        $table = new xmldb_table('course_sections_availability');

        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, XMLDB_SEQUENCE, null);
        $table->add_field('coursesectionid', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, null);
        $table->add_field('sourcecmid', XMLDB_TYPE_INTEGER, '10', null, null, null, null);
        $table->add_field('requiredcompletion', XMLDB_TYPE_INTEGER, '1', null, null, null, null);
        $table->add_field('gradeitemid', XMLDB_TYPE_INTEGER, '10', null, null, null, null);
        $table->add_field('grademin', XMLDB_TYPE_NUMBER, '10, 5', null, null, null, null);
        $table->add_field('grademax', XMLDB_TYPE_NUMBER, '10, 5', null, null, null, null);

        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
        $table->add_key('coursesectionid', XMLDB_KEY_FOREIGN, array('coursesectionid'), 'course_sections', array('id'));
        $table->add_key('sourcecmid', XMLDB_KEY_FOREIGN, array('sourcecmid'), 'course_modules', array('id'));
        $table->add_key('gradeitemid', XMLDB_KEY_FOREIGN, array('gradeitemid'), 'grade_items', array('id'));

        if (!$dbman->table_exists($table)) {
            $dbman->create_table($table);
        }

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012051100.03);
    }

    if ($oldversion < 2012052100.00) {

        // Define field referencefileid to be added to files.
        $table = new xmldb_table('files');

        // Define field referencefileid to be added to files.
        $field = new xmldb_field('referencefileid', XMLDB_TYPE_INTEGER, '10', null, null, null, null, 'sortorder');

        // Conditionally launch add field referencefileid.
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }

        // Define field referencelastsync to be added to files.
        $field = new xmldb_field('referencelastsync', XMLDB_TYPE_INTEGER, '10', null, null, null, null, 'referencefileid');

        // Conditionally launch add field referencelastsync.
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }

        // Define field referencelifetime to be added to files.
        $field = new xmldb_field('referencelifetime', XMLDB_TYPE_INTEGER, '10', null, null, null, null, 'referencelastsync');

        // Conditionally launch add field referencelifetime.
        if (!$dbman->field_exists($table, $field)) {
            $dbman->add_field($table, $field);
        }

        $key = new xmldb_key('referencefileid', XMLDB_KEY_FOREIGN, array('referencefileid'), 'files_reference', array('id'));
        // Launch add key referencefileid
        $dbman->add_key($table, $key);

        // Define table files_reference to be created.
        $table = new xmldb_table('files_reference');

        // Adding fields to table files_reference.
        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, XMLDB_SEQUENCE, null);
        $table->add_field('repositoryid', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, null);
        $table->add_field('lastsync', XMLDB_TYPE_INTEGER, '10', null, null, null, null);
        $table->add_field('lifetime', XMLDB_TYPE_INTEGER, '10', null, null, null, null);
        $table->add_field('reference', XMLDB_TYPE_TEXT, null, null, null, null, null);

        // Adding keys to table files_reference.
        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
        $table->add_key('repositoryid', XMLDB_KEY_FOREIGN, array('repositoryid'), 'repository_instances', array('id'));

        // Conditionally launch create table for files_reference
        if (!$dbman->table_exists($table)) {
            $dbman->create_table($table);
        }

        // Main savepoint reached
        upgrade_main_savepoint(true, 2012052100.00);
    }

    return true;
}