PHP upgrade_main_savepoint函数代码示例

function xmldb_main_upgrade($oldversion = 0)
{
    global $CFG, $THEME, $USER, $SITE, $db;
    $result = true;
    if ($result && $oldversion < 2006100401) {
        /// Only for those tracking Moodle 1.7 dev, others will have these dropped in moodle_install_roles()
        if (!empty($CFG->rolesactive)) {
            drop_table(new XMLDBTable('user_students'));
            drop_table(new XMLDBTable('user_teachers'));
            drop_table(new XMLDBTable('user_coursecreators'));
            drop_table(new XMLDBTable('user_admins'));
        }
        upgrade_main_savepoint($result, 2006100401);
    }
    if ($result && $oldversion < 2006100601) {
        /// Disable the exercise module because it's unmaintained
        if ($module = get_record('modules', 'name', 'exercise')) {
            if ($module->visible) {
                // Hide/disable the module entry
                set_field('modules', 'visible', '0', 'id', $module->id);
                // Save existing visible state for all activities
                set_field('course_modules', 'visibleold', '1', 'visible', '1', 'module', $module->id);
                set_field('course_modules', 'visibleold', '0', 'visible', '0', 'module', $module->id);
                // Hide all activities
                set_field('course_modules', 'visible', '0', 'module', $module->id);
                //require_once($CFG->dirroot.'/course/lib.php');
                //rebuild_course_cache();  // Rebuld cache for all modules because they might have changed
            }
        }
        upgrade_main_savepoint($result, 2006100601);
    }
    if ($result && $oldversion < 2006101001) {
        /// Disable the LAMS module by default (if it is installed)
        if (count_records('modules', 'name', 'lams') && !count_records('lams')) {
            set_field('modules', 'visible', 0, 'name', 'lams');
            // Disable it by default
        }
        upgrade_main_savepoint($result, 2006101001);
    }
    if ($result && $oldversion < 2006102600) {
        /// Define fields to be added to user_info_field
        $table = new XMLDBTable('user_info_field');
        $field = new XMLDBField('description');
        $field->setAttributes(XMLDB_TYPE_TEXT, 'big', null, null, null, null, null, null, 'categoryid');
        $field1 = new XMLDBField('param1');
        $field1->setAttributes(XMLDB_TYPE_TEXT, 'big', null, null, null, null, null, null, 'defaultdata');
        $field2 = new XMLDBField('param2');
        $field2->setAttributes(XMLDB_TYPE_TEXT, 'big', null, null, null, null, null, null, 'param1');
        $field3 = new XMLDBField('param3');
        $field3->setAttributes(XMLDB_TYPE_TEXT, 'big', null, null, null, null, null, null, 'param2');
        $field4 = new XMLDBField('param4');
        $field4->setAttributes(XMLDB_TYPE_TEXT, 'big', null, null, null, null, null, null, 'param3');
        $field5 = new XMLDBField('param5');
        $field5->setAttributes(XMLDB_TYPE_TEXT, 'big', null, null, null, null, null, null, 'param4');
        /// Launch add fields
        $result = $result && add_field($table, $field);
        $result = $result && add_field($table, $field1);
        $result = $result && add_field($table, $field2);
        $result = $result && add_field($table, $field3);
        $result = $result && add_field($table, $field4);
        $result = $result && add_field($table, $field5);
        upgrade_main_savepoint($result, 2006102600);
    }
    if ($result && $oldversion < 2006112000) {
        /// Define field attachment to be added to post
        $table = new XMLDBTable('post');
        $field = new XMLDBField('attachment');
        $field->setAttributes(XMLDB_TYPE_CHAR, '100', null, null, null, null, null, null, 'format');
        /// Launch add field attachment
        $result = $result && add_field($table, $field);
        upgrade_main_savepoint($result, 2006112000);
    }
    if ($result && $oldversion < 2006112200) {
        /// Define field imagealt to be added to user
        $table = new XMLDBTable('user');
        $field = new XMLDBField('imagealt');
        $field->setAttributes(XMLDB_TYPE_CHAR, '255', null, null, null, null, null, null, 'trustbitmask');
        /// Launch add field imagealt
        $result = $result && add_field($table, $field);
        $table = new XMLDBTable('user');
        $field = new XMLDBField('screenreader');
        $field->setAttributes(XMLDB_TYPE_INTEGER, '1', null, XMLDB_NOTNULL, null, null, null, '0', 'imagealt');
        /// Launch add field screenreader
        $result = $result && add_field($table, $field);
        upgrade_main_savepoint($result, 2006112200);
    }
    if ($result && $oldversion < 2006120300) {
        /// Delete guest course section settings
        // following code can be executed repeatedly, such as when upgrading from 1.7.x - it is ok
        if ($guest = get_record('user', 'username', 'guest')) {
            execute_sql("DELETE FROM {$CFG->prefix}course_display where userid={$guest->id}", true);
        }
        upgrade_main_savepoint($result, 2006120300);
    }
    if ($result && $oldversion < 2006120400) {
        /// Remove secureforms config setting
        execute_sql("DELETE FROM {$CFG->prefix}config where name='secureforms'", true);
        upgrade_main_savepoint($result, 2006120400);
    }
    if (!empty($CFG->rolesactive) && $oldversion < 2006120700) {
//.........这里部分代码省略.........

/**
 * Upgrade moodle core
 * @param float $version target version
 * @param bool $verbose
 * @return void, may throw exception
 */
function upgrade_core($version, $verbose) {
    global $CFG, $SITE, $DB, $COURSE;

    raise_memory_limit(MEMORY_EXTRA);

    require_once($CFG->libdir.'/db/upgrade.php');    // Defines upgrades

    try {
        // Reset caches before any output.
        cache_helper::purge_all(true);
        purge_all_caches();

        // Upgrade current language pack if we can
        upgrade_language_pack();

        print_upgrade_part_start('moodle', false, $verbose);

        // Pre-upgrade scripts for local hack workarounds.
        $preupgradefile = "$CFG->dirroot/local/preupgrade.php";
        if (file_exists($preupgradefile)) {
            core_php_time_limit::raise();
            require($preupgradefile);
            // Reset upgrade timeout to default.
            upgrade_set_timeout();
        }

        $result = xmldb_main_upgrade($CFG->version);
        if ($version > $CFG->version) {
            // store version if not already there
            upgrade_main_savepoint($result, $version, false);
        }

        // In case structure of 'course' table has been changed and we forgot to update $SITE, re-read it from db.
        $SITE = $DB->get_record('course', array('id' => $SITE->id));
        $COURSE = clone($SITE);

        // perform all other component upgrade routines
        update_capabilities('moodle');
        log_update_descriptions('moodle');
        external_update_descriptions('moodle');
        events_update_definition('moodle');
        \core\task\manager::reset_scheduled_tasks_for_component('moodle');
        message_update_providers('moodle');
        \core\message\inbound\manager::update_handlers_for_component('moodle');
        // Update core definitions.
        cache_helper::update_definitions(true);

        // Purge caches again, just to be sure we arn't holding onto old stuff now.
        cache_helper::purge_all(true);
        purge_all_caches();

        // Clean up contexts - more and more stuff depends on existence of paths and contexts
        context_helper::cleanup_instances();
        context_helper::create_instances(null, false);
        context_helper::build_all_paths(false);
        $syscontext = context_system::instance();
        $syscontext->mark_dirty();

        print_upgrade_part_end('moodle', false, $verbose);
    } catch (Exception $ex) {
        upgrade_handle_exception($ex);
    }
}

/**
 * Upgrade moodle core
 * @param float $version target version
 * @param bool $verbose
 * @return void, may throw exception
 */
function upgrade_core($version, $verbose)
{
    global $CFG;
    require_once $CFG->libdir . '/db/upgrade.php';
    // Defines upgrades
    try {
        // Upgrade current language pack if we can
        if (empty($CFG->skiplangupgrade)) {
            upgrade_language_pack(false);
        }
        print_upgrade_part_start('moodle', false, $verbose);
        // one time special local migration pre 2.0 upgrade script
        if ($version < 2007101600) {
            $pre20upgradefile = "{$CFG->dirrot}/local/upgrade_pre20.php";
            if (file_exists($pre20upgradefile)) {
                set_time_limit(0);
                require $pre20upgradefile;
                // reset upgrade timeout to default
                upgrade_set_timeout();
            }
        }
        $result = xmldb_main_upgrade($CFG->version);
        if ($version > $CFG->version) {
            // store version if not already there
            upgrade_main_savepoint($result, $version, false);
        }
        // perform all other component upgrade routines
        update_capabilities('moodle');
        events_update_definition('moodle');
        message_update_providers('moodle');
        remove_dir($CFG->dataroot . '/cache', true);
        // flush cache
        print_upgrade_part_end('moodle', false, $verbose);
    } catch (Exception $ex) {
        upgrade_handle_exception($ex);
    }
}

/**
 * Upgrade moodle core
 * @param float $version target version
 * @param bool $verbose
 * @return void, may throw exception
 */
function upgrade_core($version, $verbose) {
    global $CFG;

    raise_memory_limit(MEMORY_EXTRA);

    require_once($CFG->libdir.'/db/upgrade.php');    // Defines upgrades

    try {
        // Reset caches before any output
        purge_all_caches();

        // Upgrade current language pack if we can
        upgrade_language_pack();

        print_upgrade_part_start('moodle', false, $verbose);

        // one time special local migration pre 2.0 upgrade script
        if ($CFG->version < 2007101600) {
            $pre20upgradefile = "$CFG->dirroot/local/upgrade_pre20.php";
            if (file_exists($pre20upgradefile)) {
                set_time_limit(0);
                require($pre20upgradefile);
                // reset upgrade timeout to default
                upgrade_set_timeout();
            }
        }

        $result = xmldb_main_upgrade($CFG->version);
        if ($version > $CFG->version) {
            // store version if not already there
            upgrade_main_savepoint($result, $version, false);
        }

        // perform all other component upgrade routines
        update_capabilities('moodle');
        log_update_descriptions('moodle');
        external_update_descriptions('moodle');
        events_update_definition('moodle');
        message_update_providers('moodle');

        // Reset caches again, just to be sure
        purge_all_caches();

        // Clean up contexts - more and more stuff depends on existence of paths and contexts
        context_helper::cleanup_instances();
        context_helper::create_instances(null, false);
        context_helper::build_all_paths(false);
        $syscontext = context_system::instance();
        $syscontext->mark_dirty();

        print_upgrade_part_end('moodle', false, $verbose);
    } catch (Exception $ex) {
        upgrade_handle_exception($ex);
    }
}

/**
 * Upgrade moodle core
 * @param float $version target version
 * @param bool $verbose
 * @return void, may throw exception
 */
function upgrade_core($version, $verbose)
{
    global $CFG;
    raise_memory_limit(MEMORY_EXTRA);
    require_once $CFG->libdir . '/db/upgrade.php';
    // Defines upgrades
    try {
        // Reset caches before any output
        purge_all_caches();
        // Disable the use of cache stores here. We will reset the factory after we've performed the installation.
        // This ensures that we don't permanently cache anything during installation.
        cache_factory::disable_stores();
        // Upgrade current language pack if we can
        upgrade_language_pack();
        print_upgrade_part_start('moodle', false, $verbose);
        // one time special local migration pre 2.0 upgrade script
        if ($CFG->version < 2007101600) {
            $pre20upgradefile = "{$CFG->dirroot}/local/upgrade_pre20.php";
            if (file_exists($pre20upgradefile)) {
                set_time_limit(0);
                require $pre20upgradefile;
                // reset upgrade timeout to default
                upgrade_set_timeout();
            }
        }
        $result = xmldb_main_upgrade($CFG->version);
        if ($version > $CFG->version) {
            // store version if not already there
            upgrade_main_savepoint($result, $version, false);
        }
        // perform all other component upgrade routines
        update_capabilities('moodle');
        log_update_descriptions('moodle');
        external_update_descriptions('moodle');
        events_update_definition('moodle');
        message_update_providers('moodle');
        // Update core definitions.
        cache_helper::update_definitions(true);
        // Reset the cache, this returns it to a normal operation state.
        cache_factory::reset();
        // Purge caches again, just to be sure we arn't holding onto old stuff now.
        purge_all_caches();
        // Clean up contexts - more and more stuff depends on existence of paths and contexts
        context_helper::cleanup_instances();
        context_helper::create_instances(null, false);
        context_helper::build_all_paths(false);
        $syscontext = context_system::instance();
        $syscontext->mark_dirty();
        print_upgrade_part_end('moodle', false, $verbose);
    } catch (Exception $ex) {
        upgrade_handle_exception($ex);
    }
}

            print_upgrade_reload('index.php?confirmupgrade=1&confirmrelease=1');
            print_continue('index.php?confirmupgrade=1&confirmrelease=1&confirmplugincheck=1');
            print_footer('none');
            die;
        } else {
            /// Launch main upgrade
            try {
                // Upgrade current language pack if we can
                if (empty($CFG->skiplangupgrade)) {
                    upgrade_language_pack(false);
                }
                print_upgrade_part_start('moodle', false);
                $result = xmldb_main_upgrade($CFG->version);
                if ($version > $CFG->version) {
                    // store version if not already there
                    upgrade_main_savepoint($result, $version, false);
                }
                // perform all other component upgrade routines
                update_capabilities('moodle');
                events_update_definition('moodle');
                message_update_providers('moodle');
                message_update_providers('message');
                remove_dir($CFG->dataroot . '/cache', true);
                // flush cache
                print_upgrade_part_end('moodle', false);
            } catch (Exception $ex) {
                upgrade_handle_exception($ex);
            }
        }
    }
} else {

/**
 * 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);
//.........这里部分代码省略.........

/**
 * 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, $SITE;
    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);
//.........这里部分代码省略.........

/**
 * 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);
//.........这里部分代码省略.........

/**
 * Upgrade moodle core
 * @param float $version target version
 * @param bool $verbose
 * @return void, may throw exception
 */
function upgrade_core($version, $verbose)
{
    global $CFG;
    raise_memory_limit(MEMORY_EXTRA);
    require_once $CFG->libdir . '/db/upgrade.php';
    // Defines upgrades
    try {
        // Reset caches before any output.
        cache_helper::purge_all(true);
        purge_all_caches();
        // Upgrade current language pack if we can
        upgrade_language_pack();
        print_upgrade_part_start('moodle', false, $verbose);
        // Pre-upgrade scripts for local hack workarounds.
        $preupgradefile = "{$CFG->dirroot}/local/preupgrade.php";
        if (file_exists($preupgradefile)) {
            core_php_time_limit::raise();
            require $preupgradefile;
            // Reset upgrade timeout to default.
            upgrade_set_timeout();
        }
        $result = xmldb_main_upgrade($CFG->version);
        if ($version > $CFG->version) {
            // store version if not already there
            upgrade_main_savepoint($result, $version, false);
        }
        // perform all other component upgrade routines
        update_capabilities('moodle');
        log_update_descriptions('moodle');
        external_update_descriptions('moodle');
        events_update_definition('moodle');
        message_update_providers('moodle');
        // Update core definitions.
        cache_helper::update_definitions(true);
        // Purge caches again, just to be sure we arn't holding onto old stuff now.
        cache_helper::purge_all(true);
        purge_all_caches();
        // Clean up contexts - more and more stuff depends on existence of paths and contexts
        context_helper::cleanup_instances();
        context_helper::create_instances(null, false);
        context_helper::build_all_paths(false);
        $syscontext = context_system::instance();
        $syscontext->mark_dirty();
        print_upgrade_part_end('moodle', false, $verbose);
    } catch (Exception $ex) {
        upgrade_handle_exception($ex);
    }
}

/**
 * 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, $DB;
    require_once $CFG->libdir . '/db/upgradelib.php';
    // Core Upgrade-related functions.
    $dbman = $DB->get_manager();
    // Loads ddl manager and xmldb classes.
    // Always keep this upgrade step with version being the minimum
    // allowed version to upgrade from (v2.7.0 right now).
    if ($oldversion < 2014051200) {
        // Just in case somebody hacks upgrade scripts or env, we really can not continue.
        echo "You need to upgrade to 2.7.x or higher first!\n";
        exit(1);
        // Note this savepoint is 100% unreachable, but needed to pass the upgrade checks.
        upgrade_main_savepoint(true, 2014051200);
    }
    // MDL-32543 Make sure that the log table has correct length for action and url fields.
    if ($oldversion < 2014051200.02) {
        $table = new xmldb_table('log');
        $columns = $DB->get_columns('log');
        if ($columns['action']->max_length < 40) {
            $index1 = new xmldb_index('course-module-action', XMLDB_INDEX_NOTUNIQUE, array('course', 'module', 'action'));
            if ($dbman->index_exists($table, $index1)) {
                $dbman->drop_index($table, $index1);
            }
            $index2 = new xmldb_index('action', XMLDB_INDEX_NOTUNIQUE, array('action'));
            if ($dbman->index_exists($table, $index2)) {
                $dbman->drop_index($table, $index2);
            }
            $field = new xmldb_field('action', XMLDB_TYPE_CHAR, '40', null, XMLDB_NOTNULL, null, null, 'cmid');
            $dbman->change_field_precision($table, $field);
            $dbman->add_index($table, $index1);
            $dbman->add_index($table, $index2);
        }
        if ($columns['url']->max_length < 100) {
            $field = new xmldb_field('url', XMLDB_TYPE_CHAR, '100', null, XMLDB_NOTNULL, null, null, 'action');
            $dbman->change_field_precision($table, $field);
        }
        upgrade_main_savepoint(true, 2014051200.02);
    }
    if ($oldversion < 2014060300.0) {
        $gspath = get_config('assignfeedback_editpdf', 'gspath');
        if ($gspath !== false) {
            set_config('pathtogs', $gspath);
            unset_config('gspath', 'assignfeedback_editpdf');
        }
        upgrade_main_savepoint(true, 2014060300.0);
    }
    if ($oldversion < 2014061000.0) {
        // Fixing possible wrong MIME type for Publisher files.
        $filetypes = array('%.pub' => 'application/x-mspublisher');
        upgrade_mimetypes($filetypes);
        upgrade_main_savepoint(true, 2014061000.0);
    }
    if ($oldversion < 2014062600.01) {
        // We only want to delete DragMath if the directory no longer exists. If the directory
        // is present then it means it has been restored, so do not perform the uninstall.
        if (!check_dir_exists($CFG->libdir . '/editor/tinymce/plugins/dragmath', false)) {
//.........这里部分代码省略.........

function xmldb_main_upgrade($oldversion)
{
    global $CFG, $THEME, $USER, $DB, $OUTPUT;
    require_once $CFG->libdir . '/db/upgradelib.php';
    // Core Upgrade-related functions
    $result = true;
    $dbman = $DB->get_manager();
    // loads ddl manager and xmldb classes
    ////////////////////////////////////////
    ///upgrade supported only from 1.9.x ///
    ////////////////////////////////////////
    if ($result && $oldversion < 2008030600) {
        //NOTE: this table was added much later, that is why this step is repeated later in this file
        /// Define table upgrade_log to be created
        $table = new xmldb_table('upgrade_log');
        /// Adding fields to table upgrade_log
        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, XMLDB_SEQUENCE, null);
        $table->add_field('type', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, null);
        $table->add_field('plugin', XMLDB_TYPE_CHAR, '100', null, null, null, null);
        $table->add_field('version', XMLDB_TYPE_CHAR, '100', null, null, null, null);
        $table->add_field('info', XMLDB_TYPE_CHAR, '255', null, XMLDB_NOTNULL, null, null);
        $table->add_field('details', XMLDB_TYPE_TEXT, 'small', null, null, null, null);
        $table->add_field('backtrace', XMLDB_TYPE_TEXT, 'small', null, null, null, null);
        $table->add_field('userid', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null);
        $table->add_field('timemodified', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null);
        /// Adding keys to table upgrade_log
        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
        $table->add_key('userid', XMLDB_KEY_FOREIGN, array('userid'), 'user', array('id'));
        /// Adding indexes to table upgrade_log
        $table->add_index('timemodified', XMLDB_INDEX_NOTUNIQUE, array('timemodified'));
        $table->add_index('type-timemodified', XMLDB_INDEX_NOTUNIQUE, array('type', 'timemodified'));
        /// Create table for upgrade_log
        $dbman->create_table($table);
        /// Main savepoint reached
        upgrade_main_savepoint($result, 2008030600);
    }
    if ($result && $oldversion < 2008030700) {
        upgrade_set_timeout(60 * 20);
        // this may take a while
        /// Define index contextid-lowerboundary (not unique) to be dropped form grade_letters
        $table = new xmldb_table('grade_letters');
        $index = new xmldb_index('contextid-lowerboundary', XMLDB_INDEX_NOTUNIQUE, array('contextid', 'lowerboundary'));
        /// Launch drop index contextid-lowerboundary
        $dbman->drop_index($table, $index);
        /// Define index contextid-lowerboundary-letter (unique) to be added to grade_letters
        $table = new xmldb_table('grade_letters');
        $index = new xmldb_index('contextid-lowerboundary-letter', XMLDB_INDEX_UNIQUE, array('contextid', 'lowerboundary', 'letter'));
        /// Launch add index contextid-lowerboundary-letter
        $dbman->add_index($table, $index);
        /// Main savepoint reached
        upgrade_main_savepoint($result, 2008030700);
    }
    if ($result && $oldversion < 2008050100) {
        // Update courses that used weekscss to weeks
        $result = $DB->set_field('course', 'format', 'weeks', array('format' => 'weekscss'));
        upgrade_main_savepoint($result, 2008050100);
    }
    if ($result && $oldversion < 2008050200) {
        // remove unused config options
        unset_config('statsrolesupgraded');
        upgrade_main_savepoint($result, 2008050200);
    }
    if ($result && $oldversion < 2008050700) {
        upgrade_set_timeout(60 * 20);
        // this may take a while
        /// Fix minor problem caused by MDL-5482.
        require_once $CFG->dirroot . '/question/upgrade.php';
        $result = $result && question_fix_random_question_parents();
        upgrade_main_savepoint($result, 2008050700);
    }
    if ($result && $oldversion < 2008051200) {
        // if guest role used as default user role unset it and force admin to choose new setting
        if (!empty($CFG->defaultuserroleid)) {
            if ($role = $DB->get_record('role', array('id' => $CFG->defaultuserroleid))) {
                if ($guestroles = get_roles_with_capability('moodle/legacy:guest', CAP_ALLOW)) {
                    if (isset($guestroles[$role->id])) {
                        set_config('defaultuserroleid', null);
                        echo $OUTPUT->notification('Guest role removed from "Default role for all users" setting, please select another role.', 'notifysuccess');
                    }
                }
            } else {
                set_config('defaultuserroleid', null);
            }
        }
        /// Main savepoint reached
        upgrade_main_savepoint($result, 2008051200);
    }
    if ($result && $oldversion < 2008051201) {
        echo $OUTPUT->notification('Increasing size of user idnumber field, this may take a while...', 'notifysuccess');
        upgrade_set_timeout(60 * 20);
        // this may take a while
        /// Under MySQL and Postgres... detect old NULL contents and change them by correct empty string. MDL-14859
        $dbfamily = $DB->get_dbfamily();
        if ($dbfamily === 'mysql' || $dbfamily === 'postgres') {
            $DB->execute("UPDATE {user} SET idnumber = '' WHERE idnumber IS NULL");
        }
        /// Define index idnumber (not unique) to be dropped form user
        $table = new xmldb_table('user');
        $index = new xmldb_index('idnumber', XMLDB_INDEX_NOTUNIQUE, array('idnumber'));
        /// Launch drop index idnumber
//.........这里部分代码省略.........

/**
 * 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, $SITE;

    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);
    }
//.........这里部分代码省略.........

/**
 * 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, $SITE, $COURSE;
    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);
//.........这里部分代码省略.........

/**
 *
 * @global stdClass $CFG
 * @global stdClass $USER
 * @global moodle_database $DB
 * @global core_renderer $OUTPUT
 * @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 = $DB->get_manager();
    // loads ddl manager and xmldb classes
    ////////////////////////////////////////
    ///upgrade supported only from 1.9.x ///
    ////////////////////////////////////////
    if ($oldversion < 2008030600) {
        //NOTE: this table was added much later later in dev cycle, but we need it here, upgrades from pre PR1 not supported
        /// Define table upgrade_log to be created
        $table = new xmldb_table('upgrade_log');
        /// Adding fields to table upgrade_log
        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, XMLDB_SEQUENCE, null);
        $table->add_field('type', XMLDB_TYPE_INTEGER, '10', null, XMLDB_NOTNULL, null, null);
        $table->add_field('plugin', XMLDB_TYPE_CHAR, '100', null, null, null, null);
        $table->add_field('version', XMLDB_TYPE_CHAR, '100', null, null, null, null);
        $table->add_field('targetversion', XMLDB_TYPE_CHAR, '100', null, null, null, null);
        $table->add_field('info', XMLDB_TYPE_CHAR, '255', null, XMLDB_NOTNULL, null, null);
        $table->add_field('details', XMLDB_TYPE_TEXT, 'small', null, null, null, null);
        $table->add_field('backtrace', XMLDB_TYPE_TEXT, 'small', null, null, null, null);
        $table->add_field('userid', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null);
        $table->add_field('timemodified', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null);
        /// Adding keys to table upgrade_log
        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
        $table->add_key('userid', XMLDB_KEY_FOREIGN, array('userid'), 'user', array('id'));
        /// Adding indexes to table upgrade_log
        $table->add_index('timemodified', XMLDB_INDEX_NOTUNIQUE, array('timemodified'));
        $table->add_index('type-timemodified', XMLDB_INDEX_NOTUNIQUE, array('type', 'timemodified'));
        /// Create table for upgrade_log
        $dbman->create_table($table);
        /// Main savepoint reached
        upgrade_main_savepoint(true, 2008030600);
    }
    if ($oldversion < 2008030601) {
        //NOTE: this table was added much later later in dev cycle, but we need it here, upgrades from pre PR1 not supported
        /// Define table log_queries to be created
        $table = new xmldb_table('log_queries');
        /// Adding fields to table log_queries
        $table->add_field('id', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, XMLDB_SEQUENCE, null);
        $table->add_field('qtype', XMLDB_TYPE_INTEGER, '5', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null);
        $table->add_field('sqltext', XMLDB_TYPE_TEXT, 'medium', null, XMLDB_NOTNULL, null, null);
        $table->add_field('sqlparams', XMLDB_TYPE_TEXT, 'big', null, null, null, null);
        $table->add_field('error', XMLDB_TYPE_INTEGER, '5', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, '0');
        $table->add_field('info', XMLDB_TYPE_TEXT, 'small', null, null, null, null);
        $table->add_field('backtrace', XMLDB_TYPE_TEXT, 'small', null, null, null, null);
        $table->add_field('exectime', XMLDB_TYPE_NUMBER, '10, 5', null, XMLDB_NOTNULL, null, null);
        $table->add_field('timelogged', XMLDB_TYPE_INTEGER, '10', XMLDB_UNSIGNED, XMLDB_NOTNULL, null, null);
        /// Adding keys to table log_queries
        $table->add_key('primary', XMLDB_KEY_PRIMARY, array('id'));
        /// Conditionally launch create table for log_queries
        $dbman->create_table($table);
        /// Main savepoint reached
        upgrade_main_savepoint(true, 2008030601);
    }
    if ($oldversion < 2008030602) {
        @unlink($CFG->dataroot . '/cache/languages');
        if (file_exists("{$CFG->dataroot}/lang")) {
            // rename old lang directory so that the new and old langs do not mix
            if (rename("{$CFG->dataroot}/lang", "{$CFG->dataroot}/oldlang")) {
                $oldlang = "{$CFG->dataroot}/oldlang";
            } else {
                $oldlang = "{$CFG->dataroot}/lang";
            }
        } else {
            $oldlang = '';
        }
        // TODO: fetch previously installed languages ("*_utf8") found in $oldlang from moodle.org
        upgrade_set_timeout(60 * 20);
        // this may take a while
        // TODO: add some info file to $oldlang describing what to do with "$oldlang/*_utf8_local" dirs
        // Main savepoint reached
        upgrade_main_savepoint(true, 2008030602);
    }
    if ($oldversion < 2008030700) {
        upgrade_set_timeout(60 * 20);
        // this may take a while
        /// Define index contextid-lowerboundary (not unique) to be dropped form grade_letters
        $table = new xmldb_table('grade_letters');
        $index = new xmldb_index('contextid-lowerboundary', XMLDB_INDEX_NOTUNIQUE, array('contextid', 'lowerboundary'));
        /// Launch drop index contextid-lowerboundary
        if ($dbman->index_exists($table, $index)) {
            $dbman->drop_index($table, $index);
        }
        /// Define index contextid-lowerboundary-letter (unique) to be added to grade_letters
        $table = new xmldb_table('grade_letters');
        $index = new xmldb_index('contextid-lowerboundary-letter', XMLDB_INDEX_UNIQUE, array('contextid', 'lowerboundary', 'letter'));
        /// Launch add index contextid-lowerboundary-letter
        $dbman->add_index($table, $index);
//.........这里部分代码省略.........