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<?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/>. /** * General database export class * * @package core_dtl * @copyright 2008 Andrei Bautu * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later */ defined('MOODLE_INTERNAL') || die(); /** * Base class for database export operations. This class defines basic callbacks * for export operations and implements the @see export_database and * @export_table methods generic export processing. In general, subclasses will * override callback methods to provide specific output and (optionally) * @see export_database to add functionality. * Between a single pair of calls to @see begin_database_export and * @see finish_database_export, multiple non-overlapping pairs of calls may * be made to @see begin_table_export and @see finish_database_export for * different tables. Between one pair of calls to @see begin_table_export and * @see finish_database_export multiple calls may be made to * @see export_table_data for the same table. */ abstract class database_exporter { /** @var moodle_database Connection to the source database (a @see moodle_database object). */ protected $mdb; /** @var database_manager Database manager of the source database (a @see database_manager object). */ protected $manager; /** @var xmldb_structure Source database schema in XMLDB format (a @see xmldb_structure object). */ protected $schema; /** * Boolean flag - whether or not to check that XML database schema matches * the RDBMS database schema before exporting (used by * @see export_database). * @var bool */ protected $check_schema; /** * Object constructor. * * @param moodle_database $mdb Connection to the source database (a * @see moodle_database object). * @param boolean $check_schema - whether or not to check that XML database * schema matches the RDBMS database schema before exporting (used by * @see export_database). */ public function __construct(moodle_database $mdb, $check_schema=true) { $this->mdb = $mdb; $this->manager = $mdb->get_manager(); $this->schema = $this->manager->get_install_xml_schema(); $this->check_schema = $check_schema; } /** * Callback function. Should be called only once database per export * operation, before any other export operations. Subclasses should export * basic database information (version and timestamp). * * @param float $version the version of the system which generating the data * @param string $release moodle release info * @param string $timestamp the timestamp of the data (in ISO 8601) format. * @param string $description a user description of the data. * @return void */ public abstract function begin_database_export($version, $release, $timestamp, $description); /** * Callback function. Should be called only once per table export operation, * before any other table export operations. Subclasses should export * basic database information (name and schema's hash). * * @param xmldb_table $table - XMLDB object for the exported table * @return void */ public abstract function begin_table_export(xmldb_table $table); /** * Callback function. Should be called only once per table export operation, * after all other table export operations. * * @param xmldb_table $table - XMLDB object for the exported table */ public abstract function finish_table_export(xmldb_table $table); /** * Callback function. Should be called only once database per export * operation, after all database export operations. */ public abstract function finish_database_export(); /** * Callback function. Should be called only once per record export operation, * only between @see begin_table_export and @see finish_table_export calls. * It will insert table data. Subclasses should export basic record * information (data values). * * @param xmldb_table $table - XMLDB object of the table from which data was retrieved * @param object $data - data object (fields and values from record) * @return void */ public abstract function export_table_data(xmldb_table $table, $data); /** * Generic method to export the database. It checks the schema (if * @see $check_schema is true), queries the database and calls * appropriate callbacks. * * @throws dbtransfer_exception if any checking (e.g. database schema) fails * * @param string $description a user description of the data. */ public function export_database($description=null) { global $CFG; $options = [ 'changedcolumns' => false, // Column types may be fixed by transfer. 'missingindexes' => false // No need to worry about indexes for transfering data. ]; if ($this->check_schema and $errors = $this->manager->check_database_schema($this->schema, $options)) { $details = ''; foreach ($errors as $table=>$items) { $details .= '<div>'.get_string('tablex', 'dbtransfer', $table); $details .= '<ul>'; foreach ($items as $item) { $details .= '<li>'.$item.'</li>'; } $details .= '</ul></div>'; } throw new dbtransfer_exception('exportschemaexception', $details); } $tables = $this->schema->getTables(); $this->begin_database_export($CFG->version, $CFG->release, date('c'), $description); foreach ($tables as $table) { $rs = $this->mdb->export_table_recordset($table->getName()); if (!$rs) { throw new ddl_table_missing_exception($table->getName()); } $this->begin_table_export($table); foreach ($rs as $row) { $this->export_table_data($table, $row); } $this->finish_table_export($table); $rs->close(); } $this->finish_database_export(); } }