C:/xampp/htdocs/moodle/lib/ddl/database_manager.php

Go to the documentation of this file.

<?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/>.


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

class database_manager {

    protected $mdb;
    public $generator; // public because XMLDB editor needs to access it

    public function __construct($mdb, $generator) {
        global $CFG;

        $this->mdb       = $mdb;
        $this->generator = $generator;
    }

    public function dispose() {
        if ($this->generator) {
            $this->generator->dispose();
            $this->generator = null;
        }
        $this->mdb = null;
    }

    protected function execute_sql_arr(array $sqlarr) {
        foreach ($sqlarr as $sql) {
            $this->execute_sql($sql);
        }
    }

    protected function execute_sql($sql) {
        if (!$this->mdb->change_database_structure($sql)) {
            // in case driver does not throw exceptions yet ;-)
            throw new ddl_change_structure_exception($this->mdb->get_last_error(), $sql);
        }
    }

    public function table_exists($table) {
        if (!is_string($table) and !($table instanceof xmldb_table)) {
            throw new ddl_exception('ddlunknownerror', NULL, 'incorrect table parameter!');
        }
        return $this->generator->table_exists($table);
    }

    public function reset_sequence($table) {
        if (!is_string($table) and !($table instanceof xmldb_table)) {
            throw new ddl_exception('ddlunknownerror', NULL, 'incorrect table parameter!');
        }

        if (!$this->table_exists($table)) {
            throw new ddl_table_missing_exception($table);
        }

        if (!$sqlarr = $this->generator->getResetSequenceSQL($table)) {
            throw new ddl_exception('ddlunknownerror', null, 'table reset sequence sql not generated');
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function field_exists($table, $field) {
        if (is_string($table)) {
            $tablename = $table;
        } else {
            $tablename = $table->getName();
        }

        if (!$this->table_exists($table)) {
            throw new ddl_table_missing_exception($tablename);
        }

        if (is_string($field)) {
            $fieldname = $field;
        } else {
            $fieldname = $field->getName();
        }

        $columns = $this->mdb->get_columns($tablename);

        $exists = array_key_exists($fieldname,  $columns);

        return $exists;
    }

    public function find_index_name(xmldb_table $xmldb_table, xmldb_index $xmldb_index) {
        $tablename = $xmldb_table->getName();

        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($tablename);
        }

        $indcolumns = $xmldb_index->getFields();

        $indexes = $this->mdb->get_indexes($tablename);

        foreach ($indexes as $indexname => $index) {
            $columns = $index['columns'];
            $diferences = array_merge(array_diff($columns, $indcolumns), array_diff($indcolumns, $columns));
            if (empty($diferences)) {
                return $indexname;
            }
        }

        return false;
    }

    public function index_exists(xmldb_table $xmldb_table, xmldb_index $xmldb_index) {
        if (!$this->table_exists($xmldb_table)) {
            return false;
        }
        return ($this->find_index_name($xmldb_table, $xmldb_index) !== false);
    }

    public function find_check_constraint_name(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {

        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }

        if (!$this->field_exists($xmldb_table, $xmldb_field)) {
            throw new ddl_field_missing_exception($xmldb_field->getName(), $xmldb_table->getName());
        }

        $checks = false;
        if ($objchecks = $this->generator->getCheckConstraintsFromDB($xmldb_table, $xmldb_field)) {
            $objcheck = array_shift($objchecks);
            if ($objcheck) {
                $checks = strtolower($objcheck->name);
            }
        }

        return $checks;
    }

    public function check_constraint_exists(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        return ($this->find_check_constraint_name($xmldb_table, $xmldb_field) !== false);
    }

    public function find_key_name(xmldb_table $xmldb_table, xmldb_key $xmldb_key) {

        $keycolumns = $xmldb_key->getFields();


        if ($this->generator->primary_key_name && $xmldb_key->getType() == XMLDB_KEY_PRIMARY) {
            return $this->generator->primary_key_name;
        } else {
            switch ($xmldb_key->getType()) {
                case XMLDB_KEY_PRIMARY:
                    $suffix = 'pk';
                    break;
                case XMLDB_KEY_UNIQUE:
                    $suffix = 'uk';
                    break;
                case XMLDB_KEY_FOREIGN_UNIQUE:
                case XMLDB_KEY_FOREIGN:
                    $suffix = 'fk';
                    break;
            }
            return $this->generator->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), $suffix);
        }
    }

    public function delete_tables_from_xmldb_file($file) {

        $xmldb_file = new xmldb_file($file);

        if (!$xmldb_file->fileExists()) {
            throw new ddl_exception('ddlxmlfileerror', null, 'File does not exist');
        }

        $loaded    = $xmldb_file->loadXMLStructure();
        $structure = $xmldb_file->getStructure();

        if (!$loaded || !$xmldb_file->isLoaded()) {
            if ($structure) {
                if ($errors = $structure->getAllErrors()) {
                    throw new ddl_exception('ddlxmlfileerror', null, 'Errors found in XMLDB file: '. implode (', ', $errors));
                }
            }
            throw new ddl_exception('ddlxmlfileerror', null, 'not loaded??');
        }

        if ($xmldb_tables = $structure->getTables()) {
            foreach($xmldb_tables as $table) {
                if ($this->table_exists($table)) {
                    $this->drop_table($table);
                }
            }
        }
    }

    public function drop_table(xmldb_table $xmldb_table) {
        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }

        if (!$sqlarr = $this->generator->getDropTableSQL($xmldb_table)) {
            throw new ddl_exception('ddlunknownerror', null, 'table drop sql not generated');
        }

        $this->execute_sql_arr($sqlarr);
    }

    private function load_xmldb_file($file) {
        $xmldb_file = new xmldb_file($file);

        if (!$xmldb_file->fileExists()) {
            throw new ddl_exception('ddlxmlfileerror', null, 'File does not exist');
        }

        $loaded = $xmldb_file->loadXMLStructure();
        if (!$loaded || !$xmldb_file->isLoaded()) {
            if ($structure =& $xmldb_file->getStructure()) {
                if ($errors = $structure->getAllErrors()) {
                    throw new ddl_exception('ddlxmlfileerror', null, 'Errors found in XMLDB file: '. implode (', ', $errors));
                }
            }
            throw new ddl_exception('ddlxmlfileerror', null, 'not loaded??');
        }

        return $xmldb_file;
    }

    public function install_from_xmldb_file($file) {
        $xmldb_file = $this->load_xmldb_file($file);
        $xmldb_structure = $xmldb_file->getStructure();
        $this->install_from_xmldb_structure($xmldb_structure);
    }

    public function install_one_table_from_xmldb_file($file, $tablename, $cachestructures = false) {

        static $xmldbstructurecache = array(); // To store cached structures
        if (!empty($xmldbstructurecache) && array_key_exists($file, $xmldbstructurecache)) {
            $xmldb_structure = $xmldbstructurecache[$file];
        } else {
            $xmldb_file = $this->load_xmldb_file($file);
            $xmldb_structure = $xmldb_file->getStructure();
            if ($cachestructures) {
                $xmldbstructurecache[$file] = $xmldb_structure;
            }
        }

        $targettable = $xmldb_structure->getTable($tablename);
        if (is_null($targettable)) {
            throw new ddl_exception('ddlunknowntable', null, 'The table ' . $tablename . ' is not defined in file ' . $file);
        }
        $targettable->setNext(NULL);
        $targettable->setPrevious(NULL);

        $tempstructure = new xmldb_structure('temp');
        $tempstructure->addTable($targettable);
        $this->install_from_xmldb_structure($tempstructure);
    }

    public function install_from_xmldb_structure($xmldb_structure) {

        if (!$sqlarr = $this->generator->getCreateStructureSQL($xmldb_structure)) {
            return; // nothing to do
        }
        $this->execute_sql_arr($sqlarr);
    }

    public function create_table(xmldb_table $xmldb_table) {
        if ($this->table_exists($xmldb_table)) {
            throw new ddl_exception('ddltablealreadyexists', $xmldb_table->getName());
        }

        if (!$sqlarr = $this->generator->getCreateTableSQL($xmldb_table)) {
            throw new ddl_exception('ddlunknownerror', null, 'table create sql not generated');
        }
        $this->execute_sql_arr($sqlarr);
    }

    public function create_temp_table(xmldb_table $xmldb_table) {

        // Check table doesn't exist
        if ($this->table_exists($xmldb_table)) {
            throw new ddl_exception('ddltablealreadyexists', $xmldb_table->getName());
        }

        if (!$sqlarr = $this->generator->getCreateTempTableSQL($xmldb_table)) {
            throw new ddl_exception('ddlunknownerror', null, 'temp table create sql not generated');
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function drop_temp_table(xmldb_table $xmldb_table) {

        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }

        if (!$sqlarr = $this->generator->getDropTempTableSQL($xmldb_table)) {
            throw new ddl_exception('ddlunknownerror', null, 'temp table drop sql not generated');
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function rename_table(xmldb_table $xmldb_table, $newname) {
        if (!$newname) {
            throw new ddl_exception('ddlunknownerror', null, 'newname can not be empty');
        }

        $check = new xmldb_table($newname);

        if (!$this->table_exists($xmldb_table)) {
            if ($this->table_exists($check)) {
                throw new ddl_exception('ddlunknownerror', null, 'table probably already renamed');
            } else {
                throw new ddl_table_missing_exception($xmldb_table->getName());
            }
        }

        if ($this->table_exists($check)) {
            throw new ddl_exception('ddltablealreadyexists', $xmldb_table->getName(), 'can not rename table');
        }

        if (!$sqlarr = $this->generator->getRenameTableSQL($xmldb_table, $newname)) {
            throw new ddl_exception('ddlunknownerror', null, 'table rename sql not generated');
        }

        $this->execute_sql_arr($sqlarr);
    }


    public function add_field(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        if ($this->field_exists($xmldb_table, $xmldb_field)) {
            throw new ddl_exception('ddlfieldalreadyexists', $xmldb_field->getName());
        }

        if ($xmldb_field->getNotNull() && $this->generator->getDefaultValue($xmldb_field) === NULL && $this->mdb->count_records($xmldb_table->getName())) {
            throw new ddl_exception('ddlunknownerror', null, 'Field ' . $xmldb_table->getName() . '->' . $xmldb_field->getName() .
                      ' cannot be added. Not null fields added to non empty tables require default value. Create skipped');
        }

        if (!$sqlarr = $this->generator->getAddFieldSQL($xmldb_table, $xmldb_field)) {
            throw new ddl_exception('ddlunknownerror', null, 'addfield sql not generated');
        }
        $this->execute_sql_arr($sqlarr);
    }

    public function drop_field(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }
        if (!$this->field_exists($xmldb_table, $xmldb_field)) {
            throw new ddl_field_missing_exception($xmldb_field->getName(), $xmldb_table->getName());
        }
        $this->check_field_dependencies($xmldb_table, $xmldb_field);

        if (!$sqlarr = $this->generator->getDropFieldSQL($xmldb_table, $xmldb_field)) {
            throw new ddl_exception('ddlunknownerror', null, 'drop_field sql not generated');
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function change_field_type(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }
        if (!$this->field_exists($xmldb_table, $xmldb_field)) {
            throw new ddl_field_missing_exception($xmldb_field->getName(), $xmldb_table->getName());
        }
        $this->check_field_dependencies($xmldb_table, $xmldb_field);

        if (!$sqlarr = $this->generator->getAlterFieldSQL($xmldb_table, $xmldb_field)) {
            return; // probably nothing to do
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function change_field_precision(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        $this->change_field_type($xmldb_table, $xmldb_field);
    }

    public function change_field_unsigned(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        $this->change_field_type($xmldb_table, $xmldb_field);
    }

    public function change_field_notnull(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        $this->change_field_type($xmldb_table, $xmldb_field);
    }

    public function change_field_default(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }
        if (!$this->field_exists($xmldb_table, $xmldb_field)) {
            throw new ddl_field_missing_exception($xmldb_field->getName(), $xmldb_table->getName());
        }
        $this->check_field_dependencies($xmldb_table, $xmldb_field);

        if (!$sqlarr = $this->generator->getModifyDefaultSQL($xmldb_table, $xmldb_field)) {
            return; //Empty array = nothing to do = no error
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function drop_enum_from_field(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {
        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }
        if (!$this->field_exists($xmldb_table, $xmldb_field)) {
            throw new ddl_field_missing_exception($xmldb_field->getName(), $xmldb_table->getName());
        }

        if (!$this->check_constraint_exists($xmldb_table, $xmldb_field)) {
            debugging('Enum for ' . $xmldb_table->getName() . '->' . $xmldb_field->getName() .
                      ' does not exist. Delete skipped', DEBUG_DEVELOPER);
            return; //Enum does not exist, nothing to delete
        }

        if (!$sqlarr = $this->generator->getDropEnumSQL($xmldb_table, $xmldb_field)) {
            return; //Empty array = nothing to do = no error
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function rename_field(xmldb_table $xmldb_table, xmldb_field $xmldb_field, $newname) {
        if (empty($newname)) {
            throw new ddl_exception('ddlunknownerror', null, 'newname can not be empty');
        }

        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }

        if (!$this->field_exists($xmldb_table, $xmldb_field)) {
            throw new ddl_field_missing_exception($xmldb_field->getName(), $xmldb_table->getName());
        }

        if (!$xmldb_field->getType()) {
            throw new ddl_exception('ddlunknownerror', null,
                      'Field ' . $xmldb_table->getName() . '->' . $xmldb_field->getName() .
                      ' must contain full specs. Rename skipped');
        }

        if ($xmldb_field->getName() == 'id') {
            throw new ddl_exception('ddlunknownerror', null,
                      'Field ' . $xmldb_table->getName() . '->' . $xmldb_field->getName() .
                      ' cannot be renamed. Rename skipped');
        }

        if (!$sqlarr = $this->generator->getRenameFieldSQL($xmldb_table, $xmldb_field, $newname)) {
            return; //Empty array = nothing to do = no error
        }

        $this->execute_sql_arr($sqlarr);
    }

    private function check_field_dependencies(xmldb_table $xmldb_table, xmldb_field $xmldb_field) {

        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }

        if (!$this->field_exists($xmldb_table, $xmldb_field)) {
            throw new ddl_field_missing_exception($xmldb_field->getName(), $xmldb_table->getName());
        }

        if ($indexes = $this->mdb->get_indexes($xmldb_table->getName(), false)) {
            foreach ($indexes as $indexname => $index) {
                $columns = $index['columns'];
                if (in_array($xmldb_field->getName(), $columns)) {
                    throw new ddl_dependency_exception('column', $xmldb_table->getName() . '->' . $xmldb_field->getName(),
                                                       'index', $indexname . ' (' . implode(', ', $columns)  . ')');
                }
            }
        }
    }

    public function add_key(xmldb_table $xmldb_table, xmldb_key $xmldb_key) {

        if ($xmldb_key->getType() == XMLDB_KEY_PRIMARY) { // Prevent PRIMARY to be added (only in create table, being serious  :-P)
            throw new ddl_exception('ddlunknownerror', null, 'Primary Keys can be added at table create time only');
        }

        if (!$sqlarr = $this->generator->getAddKeySQL($xmldb_table, $xmldb_key)) {
            return; //Empty array = nothing to do = no error
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function drop_key(xmldb_table $xmldb_table, xmldb_key $xmldb_key) {
        if ($xmldb_key->getType() == XMLDB_KEY_PRIMARY) { // Prevent PRIMARY to be dropped (only in drop table, being serious  :-P)
            throw new ddl_exception('ddlunknownerror', null, 'Primary Keys can be deleted at table drop time only');
        }

        if (!$sqlarr = $this->generator->getDropKeySQL($xmldb_table, $xmldb_key)) {
            return; //Empty array = nothing to do = no error
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function rename_key(xmldb_table $xmldb_table, xmldb_key $xmldb_key, $newname) {
        debugging('rename_key() is one experimental feature. You must not use it in production!', DEBUG_DEVELOPER);

        if (!$newname) {
            throw new ddl_exception('ddlunknownerror', null, 'newname can not be empty');
        }

        if (!$sqlarr = $this->generator->getRenameKeySQL($xmldb_table, $xmldb_key, $newname)) {
            throw new ddl_exception('ddlunknownerror', null, 'Some DBs do not support key renaming (MySQL, PostgreSQL, MsSQL). Rename skipped');
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function add_index($xmldb_table, $xmldb_intex) {
        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }

        if ($this->index_exists($xmldb_table, $xmldb_intex)) {
            throw new ddl_exception('ddlunknownerror', null,
                      'Index ' . $xmldb_table->getName() . '->' . $xmldb_intex->getName() .
                      ' already exists. Create skipped');
        }

        if (!$sqlarr = $this->generator->getAddIndexSQL($xmldb_table, $xmldb_intex)) {
            throw new ddl_exception('ddlunknownerror', null, 'add_index sql not generated');
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function drop_index($xmldb_table, $xmldb_intex) {
        if (!$this->table_exists($xmldb_table)) {
            throw new ddl_table_missing_exception($xmldb_table->getName());
        }

        if (!$this->index_exists($xmldb_table, $xmldb_intex)) {
            throw new ddl_exception('ddlunknownerror', null,
                      'Index ' . $xmldb_table->getName() . '->' . $xmldb_intex->getName() .
                      ' does not exist. Drop skipped');
        }

        if (!$sqlarr = $this->generator->getDropIndexSQL($xmldb_table, $xmldb_intex)) {
            throw new ddl_exception('ddlunknownerror', null, 'drop_index sql not generated');
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function rename_index($xmldb_table, $xmldb_intex, $newname) {
        debugging('rename_index() is one experimental feature. You must not use it in production!', DEBUG_DEVELOPER);

        if (!$newname) {
            throw new ddl_exception('ddlunknownerror', null, 'newname can not be empty');
        }

        if (!$this->index_exists($xmldb_table, $xmldb_intex)) {
            throw new ddl_exception('ddlunknownerror', null,
                      'Index ' . $xmldb_table->getName() . '->' . $xmldb_intex->getName() .
                      ' does not exist. Rename skipped');
        }

        if (!$sqlarr = $this->generator->getRenameIndexSQL($xmldb_table, $xmldb_intex, $newname)) {
            throw new ddl_exception('ddlunknownerror', null, 'Some DBs do not support index renaming (MySQL). Rename skipped');
        }

        $this->execute_sql_arr($sqlarr);
    }

    public function get_install_xml_schema() {
        global $CFG;
        require_once($CFG->libdir.'/adminlib.php');

        $schema = new xmldb_structure('export');
        $schema->setVersion($CFG->version);
        $dbdirs = get_db_directories();
        foreach ($dbdirs as $dbdir) {
            $xmldb_file = new xmldb_file($dbdir.'/install.xml');
            if (!$xmldb_file->fileExists() or !$xmldb_file->loadXMLStructure()) {
                continue;
            }
            $structure = $xmldb_file->getStructure();
            $tables = $structure->getTables();
            foreach ($tables as $table) {
                $table->setPrevious(null);
                $table->setNext(null);
                $schema->addTable($table);
            }
        }
        return $schema;
    }

    public function check_database_schema(xmldb_structure $schema) {
        $errors = array();

        $dbtables = $this->mdb->get_tables();
        $tables   = $schema->getTables();

        //TODO: maybe add several levels error/warning

        // make sure that current and schema tables match exactly
        foreach ($tables as $table) {
            $tablename = $table->getName();
            if (empty($dbtables[$tablename])) {
                if (!isset($errors[$tablename])) {
                    $errors[$tablename] = array();
                }
                $errors[$tablename][] = "Table $tablename is missing in database."; //TODO: localize
                continue;
            }

            // a) check for required fields
            $dbfields = $this->mdb->get_columns($tablename);
            $fields   = $table->getFields();
            foreach ($fields as $field) {
                $fieldname = $field->getName();
                if (empty($dbfields[$fieldname])) {
                    if (!isset($errors[$tablename])) {
                        $errors[$tablename] = array();
                    }
                    $errors[$tablename][] = "Field $fieldname is missing in table $tablename.";  //TODO: localize
                }
                unset($dbfields[$fieldname]);
            }

            // b) check for extra fields (indicates unsupported hacks) - modify install.xml if you want the script to continue ;-)
            foreach ($dbfields as $fieldname=>$info) {
                if (!isset($errors[$tablename])) {
                    $errors[$tablename] = array();
                }
                $errors[$tablename][] = "Field $fieldname is not expected in table $tablename.";  //TODO: localize
            }
            unset($dbtables[$tablename]);
        }

        // look for unsupported tables - local custom tables should be in /local/xxxx/db/install.xml ;-)
        // if there is no prefix, we can not say if tale is ours :-(
        if ($this->generator->prefix !== '') {
            foreach ($dbtables as $tablename=>$unused) {
                if (strpos($tablename, 'pma_') === 0) {
                    // ignore phpmyadmin tables for now
                    continue;
                }
                if (strpos($tablename, 'test') === 0) {
                    // ignore broken results of unit tests
                    continue;
                }
                if (!isset($errors[$tablename])) {
                    $errors[$tablename] = array();
                }
                $errors[$tablename][] = "Table $tablename is not expected.";  //TODO: localize
            }
        }

        return $errors;
    }
}