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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/>.
/**
* Native mysqli class representing moodle database interface.
*
* @package core_dml
* @copyright 2008 Petr Skoda (http://skodak.org)
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
require_once(__DIR__.'/moodle_database.php');
require_once(__DIR__.'/mysqli_native_moodle_recordset.php');
require_once(__DIR__.'/mysqli_native_moodle_temptables.php');
/**
* Native mysqli class representing moodle database interface.
*
* @package core_dml
* @copyright 2008 Petr Skoda (http://skodak.org)
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class mysqli_native_moodle_database extends moodle_database {
/** @var mysqli $mysqli */
protected $mysqli = null;
/** @var bool is compressed row format supported cache */
protected $compressedrowformatsupported = null;
private $transactions_supported = null;
/**
* Attempt to create the database
* @param string $dbhost
* @param string $dbuser
* @param string $dbpass
* @param string $dbname
* @return bool success
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function create_database($dbhost, $dbuser, $dbpass, $dbname, array $dboptions=null) {
$driverstatus = $this->driver_installed();
if ($driverstatus !== true) {
throw new dml_exception('dbdriverproblem', $driverstatus);
}
if (!empty($dboptions['dbsocket'])
and (strpos($dboptions['dbsocket'], '/') !== false or strpos($dboptions['dbsocket'], '\\') !== false)) {
$dbsocket = $dboptions['dbsocket'];
} else {
$dbsocket = ini_get('mysqli.default_socket');
}
if (empty($dboptions['dbport'])) {
$dbport = (int)ini_get('mysqli.default_port');
} else {
$dbport = (int)$dboptions['dbport'];
}
// verify ini.get does not return nonsense
if (empty($dbport)) {
$dbport = 3306;
}
ob_start();
$conn = new mysqli($dbhost, $dbuser, $dbpass, '', $dbport, $dbsocket); // Connect without db
$dberr = ob_get_contents();
ob_end_clean();
$errorno = @$conn->connect_errno;
if ($errorno !== 0) {
throw new dml_connection_exception($dberr);
}
// Normally a check would be done before setting utf8mb4, but the database can be created
// before the enviroment checks are done. We'll proceed with creating the database and then do checks next.
$charset = 'utf8mb4';
if (isset($dboptions['dbcollation']) and (strpos($dboptions['dbcollation'], 'utf8_') === 0
|| strpos($dboptions['dbcollation'], 'utf8mb4_') === 0)) {
$collation = $dboptions['dbcollation'];
$collationinfo = explode('_', $dboptions['dbcollation']);
$charset = reset($collationinfo);
} else {
$collation = 'utf8mb4_unicode_ci';
}
$result = $conn->query("CREATE DATABASE $dbname DEFAULT CHARACTER SET $charset DEFAULT COLLATE ".$collation);
$conn->close();
if (!$result) {
throw new dml_exception('cannotcreatedb');
}
return true;
}
/**
* Detects if all needed PHP stuff installed.
* Note: can be used before connect()
* @return mixed true if ok, string if something
*/
public function driver_installed() {
if (!extension_loaded('mysqli')) {
return get_string('mysqliextensionisnotpresentinphp', 'install');
}
return true;
}
/**
* Returns database family type - describes SQL dialect
* Note: can be used before connect()
* @return string db family name (mysql, postgres, mssql, oracle, etc.)
*/
public function get_dbfamily() {
return 'mysql';
}
/**
* Returns more specific database driver type
* Note: can be used before connect()
* @return string db type mysqli, pgsql, oci, mssql, sqlsrv
*/
protected function get_dbtype() {
return 'mysqli';
}
/**
* Returns general database library name
* Note: can be used before connect()
* @return string db type pdo, native
*/
protected function get_dblibrary() {
return 'native';
}
/**
* Returns the current MySQL db engine.
*
* This is an ugly workaround for MySQL default engine problems,
* Moodle is designed to work best on ACID compliant databases
* with full transaction support. Do not use MyISAM.
*
* @return string or null MySQL engine name
*/
public function get_dbengine() {
if (isset($this->dboptions['dbengine'])) {
return $this->dboptions['dbengine'];
}
if ($this->external) {
return null;
}
$engine = null;
// Look for current engine of our config table (the first table that gets created),
// so that we create all tables with the same engine.
$sql = "SELECT engine
FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema = DATABASE() AND table_name = '{$this->prefix}config'";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($rec = $result->fetch_assoc()) {
// MySQL 8 BC: information_schema.* returns the fields in upper case.
$rec = array_change_key_case($rec, CASE_LOWER);
$engine = $rec['engine'];
}
$result->close();
if ($engine) {
// Cache the result to improve performance.
$this->dboptions['dbengine'] = $engine;
return $engine;
}
// Get the default database engine.
$sql = "SELECT @@default_storage_engine engine";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($rec = $result->fetch_assoc()) {
$engine = $rec['engine'];
}
$result->close();
if ($engine === 'MyISAM') {
// we really do not want MyISAM for Moodle, InnoDB or XtraDB is a reasonable defaults if supported
$sql = "SHOW STORAGE ENGINES";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
$engines = array();
while ($res = $result->fetch_assoc()) {
if ($res['Support'] === 'YES' or $res['Support'] === 'DEFAULT') {
$engines[$res['Engine']] = true;
}
}
$result->close();
if (isset($engines['InnoDB'])) {
$engine = 'InnoDB';
}
if (isset($engines['XtraDB'])) {
$engine = 'XtraDB';
}
}
// Cache the result to improve performance.
$this->dboptions['dbengine'] = $engine;
return $engine;
}
/**
* Returns the current MySQL db collation.
*
* This is an ugly workaround for MySQL default collation problems.
*
* @return string or null MySQL collation name
*/
public function get_dbcollation() {
if (isset($this->dboptions['dbcollation'])) {
return $this->dboptions['dbcollation'];
}
if ($this->external) {
return null;
}
$collation = null;
// Look for current collation of our config table (the first table that gets created),
// so that we create all tables with the same collation.
$sql = "SELECT collation_name
FROM INFORMATION_SCHEMA.COLUMNS
WHERE table_schema = DATABASE() AND table_name = '{$this->prefix}config' AND column_name = 'value'";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($rec = $result->fetch_assoc()) {
// MySQL 8 BC: information_schema.* returns the fields in upper case.
$rec = array_change_key_case($rec, CASE_LOWER);
$collation = $rec['collation_name'];
}
$result->close();
if (!$collation) {
// Get the default database collation, but only if using UTF-8.
$sql = "SELECT @@collation_database";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($rec = $result->fetch_assoc()) {
if (strpos($rec['@@collation_database'], 'utf8_') === 0 || strpos($rec['@@collation_database'], 'utf8mb4_') === 0) {
$collation = $rec['@@collation_database'];
}
}
$result->close();
}
if (!$collation) {
// We want only utf8 compatible collations.
$collation = null;
$sql = "SHOW COLLATION WHERE Collation LIKE 'utf8mb4\_%' AND Charset = 'utf8mb4'";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
while ($res = $result->fetch_assoc()) {
$collation = $res['Collation'];
if (strtoupper($res['Default']) === 'YES') {
$collation = $res['Collation'];
break;
}
}
$result->close();
}
// Cache the result to improve performance.
$this->dboptions['dbcollation'] = $collation;
return $collation;
}
/**
* Tests if the Antelope file format is still supported or it has been removed.
* When removed, only Barracuda file format is supported, given the XtraDB/InnoDB engine.
*
* @return bool True if the Antelope file format has been removed; otherwise, false.
*/
protected function is_antelope_file_format_no_more_supported() {
// Breaking change: Antelope file format support has been removed from both MySQL and MariaDB.
// The following InnoDB file format configuration parameters were deprecated and then removed:
// - innodb_file_format
// - innodb_file_format_check
// - innodb_file_format_max
// - innodb_large_prefix
// 1. MySQL: deprecated in 5.7.7 and removed 8.0.0+.
$ismysqlge8d0d0 = ($this->get_dbtype() == 'mysqli') &&
version_compare($this->get_server_info()['version'], '8.0.0', '>=');
// 2. MariaDB: deprecated in 10.2.0 and removed 10.3.1+.
$ismariadbge10d3d1 = ($this->get_dbtype() == 'mariadb') &&
version_compare($this->get_server_info()['version'], '10.3.1', '>=');
return $ismysqlge8d0d0 || $ismariadbge10d3d1;
}
/**
* Get the row format from the database schema.
*
* @param string $table
* @return string row_format name or null if not known or table does not exist.
*/
public function get_row_format($table = null) {
$rowformat = null;
if (isset($table)) {
$table = $this->mysqli->real_escape_string($table);
$sql = "SELECT row_format
FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema = DATABASE() AND table_name = '{$this->prefix}$table'";
} else {
if ($this->is_antelope_file_format_no_more_supported()) {
// Breaking change: Antelope file format support has been removed, only Barracuda.
$dbengine = $this->get_dbengine();
$supporteddbengines = array('InnoDB', 'XtraDB');
if (in_array($dbengine, $supporteddbengines)) {
$rowformat = 'Barracuda';
}
return $rowformat;
}
$sql = "SHOW VARIABLES LIKE 'innodb_file_format'";
}
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($rec = $result->fetch_assoc()) {
// MySQL 8 BC: information_schema.* returns the fields in upper case.
$rec = array_change_key_case($rec, CASE_LOWER);
if (isset($table)) {
$rowformat = $rec['row_format'];
} else {
$rowformat = $rec['value'];
}
}
$result->close();
return $rowformat;
}
/**
* Is this database compatible with compressed row format?
* This feature is necessary for support of large number of text
* columns in InnoDB/XtraDB database.
*
* @param bool $cached use cached result
* @return bool true if table can be created or changed to compressed row format.
*/
public function is_compressed_row_format_supported($cached = true) {
if ($cached and isset($this->compressedrowformatsupported)) {
return($this->compressedrowformatsupported);
}
$engine = strtolower($this->get_dbengine());
$info = $this->get_server_info();
if (version_compare($info['version'], '5.5.0') < 0) {
// MySQL 5.1 is not supported here because we cannot read the file format.
$this->compressedrowformatsupported = false;
} else if ($engine !== 'innodb' and $engine !== 'xtradb') {
// Other engines are not supported, most probably not compatible.
$this->compressedrowformatsupported = false;
} else if (!$this->is_file_per_table_enabled()) {
$this->compressedrowformatsupported = false;
} else if ($this->get_row_format() !== 'Barracuda') {
$this->compressedrowformatsupported = false;
} else {
// All the tests passed, we can safely use ROW_FORMAT=Compressed in sql statements.
$this->compressedrowformatsupported = true;
}
return $this->compressedrowformatsupported;
}
/**
* Check the database to see if innodb_file_per_table is on.
*
* @return bool True if on otherwise false.
*/
public function is_file_per_table_enabled() {
if ($filepertable = $this->get_record_sql("SHOW VARIABLES LIKE 'innodb_file_per_table'")) {
if ($filepertable->value == 'ON') {
return true;
}
}
return false;
}
/**
* Check the database to see if innodb_large_prefix is on.
*
* @return bool True if on otherwise false.
*/
public function is_large_prefix_enabled() {
if ($this->is_antelope_file_format_no_more_supported()) {
// Breaking change: Antelope file format support has been removed, only Barracuda.
return true;
}
if ($largeprefix = $this->get_record_sql("SHOW VARIABLES LIKE 'innodb_large_prefix'")) {
if ($largeprefix->value == 'ON') {
return true;
}
}
return false;
}
/**
* Determine if the row format should be set to compressed, dynamic, or default.
*
* Terrible kludge. If we're using utf8mb4 AND we're using InnoDB, we need to specify row format to
* be either dynamic or compressed (default is compact) in order to allow for bigger indexes (MySQL
* errors #1709 and #1071).
*
* @param string $engine The database engine being used. Will be looked up if not supplied.
* @param string $collation The database collation to use. Will look up the current collation if not supplied.
* @return string An sql fragment to add to sql statements.
*/
public function get_row_format_sql($engine = null, $collation = null) {
if (!isset($engine)) {
$engine = $this->get_dbengine();
}
$engine = strtolower($engine);
if (!isset($collation)) {
$collation = $this->get_dbcollation();
}
$rowformat = '';
if (($engine === 'innodb' || $engine === 'xtradb') && strpos($collation, 'utf8mb4_') === 0) {
if ($this->is_compressed_row_format_supported()) {
$rowformat = "ROW_FORMAT=Compressed";
} else {
$rowformat = "ROW_FORMAT=Dynamic";
}
}
return $rowformat;
}
/**
* Returns localised database type name
* Note: can be used before connect()
* @return string
*/
public function get_name() {
return get_string('nativemysqli', 'install');
}
/**
* Returns localised database configuration help.
* Note: can be used before connect()
* @return string
*/
public function get_configuration_help() {
return get_string('nativemysqlihelp', 'install');
}
/**
* Diagnose database and tables, this function is used
* to verify database and driver settings, db engine types, etc.
*
* @return string null means everything ok, string means problem found.
*/
public function diagnose() {
$sloppymyisamfound = false;
$prefix = str_replace('_', '\\_', $this->prefix);
$sql = "SELECT COUNT('x')
FROM INFORMATION_SCHEMA.TABLES
WHERE table_schema = DATABASE()
AND table_name LIKE BINARY '$prefix%'
AND Engine = 'MyISAM'";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($result) {
if ($arr = $result->fetch_assoc()) {
$count = reset($arr);
if ($count) {
$sloppymyisamfound = true;
}
}
$result->close();
}
if ($sloppymyisamfound) {
return get_string('myisamproblem', 'error');
} else {
return null;
}
}
/**
* Connect to db
* Must be called before other methods.
* @param string $dbhost The database host.
* @param string $dbuser The database username.
* @param string $dbpass The database username's password.
* @param string $dbname The name of the database being connected to.e
* @param mixed $prefix string means moodle db prefix, false used for external databases where prefix not used
* @param array $dboptions driver specific options
* @return bool success
*/
public function connect($dbhost, $dbuser, $dbpass, $dbname, $prefix, array $dboptions=null) {
$driverstatus = $this->driver_installed();
if ($driverstatus !== true) {
throw new dml_exception('dbdriverproblem', $driverstatus);
}
$this->store_settings($dbhost, $dbuser, $dbpass, $dbname, $prefix, $dboptions);
// dbsocket is used ONLY if host is NULL or 'localhost',
// you can not disable it because it is always tried if dbhost is 'localhost'
if (!empty($this->dboptions['dbsocket'])
and (strpos($this->dboptions['dbsocket'], '/') !== false or strpos($this->dboptions['dbsocket'], '\\') !== false)) {
$dbsocket = $this->dboptions['dbsocket'];
} else {
$dbsocket = ini_get('mysqli.default_socket');
}
if (empty($this->dboptions['dbport'])) {
$dbport = (int)ini_get('mysqli.default_port');
} else {
$dbport = (int)$this->dboptions['dbport'];
}
// verify ini.get does not return nonsense
if (empty($dbport)) {
$dbport = 3306;
}
if ($dbhost and !empty($this->dboptions['dbpersist'])) {
$dbhost = "p:$dbhost";
}
$this->mysqli = @new mysqli($dbhost, $dbuser, $dbpass, $dbname, $dbport, $dbsocket);
if ($this->mysqli->connect_errno !== 0) {
$dberr = $this->mysqli->connect_error;
$this->mysqli = null;
throw new dml_connection_exception($dberr);
}
// Disable logging until we are fully setup.
$this->query_log_prevent();
if (isset($dboptions['dbcollation'])) {
$collationinfo = explode('_', $dboptions['dbcollation']);
$this->dboptions['dbcollation'] = $dboptions['dbcollation'];
} else {
$collationinfo = explode('_', $this->get_dbcollation());
}
$charset = reset($collationinfo);
$this->query_start("--set_charset()", null, SQL_QUERY_AUX);
$this->mysqli->set_charset($charset);
$this->query_end(true);
// If available, enforce strict mode for the session. That guaranties
// standard behaviour under some situations, avoiding some MySQL nasty
// habits like truncating data or performing some transparent cast losses.
// With strict mode enforced, Moodle DB layer will be consistently throwing
// the corresponding exceptions as expected.
$si = $this->get_server_info();
if (version_compare($si['version'], '5.0.2', '>=')) {
$sql = "SET SESSION sql_mode = 'STRICT_ALL_TABLES'";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
}
// We can enable logging now.
$this->query_log_allow();
// Connection stabilised and configured, going to instantiate the temptables controller
$this->temptables = new mysqli_native_moodle_temptables($this);
return true;
}
/**
* Close database connection and release all resources
* and memory (especially circular memory references).
* Do NOT use connect() again, create a new instance if needed.
*/
public function dispose() {
parent::dispose(); // Call parent dispose to write/close session and other common stuff before closing connection
if ($this->mysqli) {
$this->mysqli->close();
$this->mysqli = null;
}
}
/**
* Returns database server info array
* @return array Array containing 'description' and 'version' info
*/
public function get_server_info() {
return array('description'=>$this->mysqli->server_info, 'version'=>$this->mysqli->server_info);
}
/**
* Returns supported query parameter types
* @return int bitmask of accepted SQL_PARAMS_*
*/
protected function allowed_param_types() {
return SQL_PARAMS_QM;
}
/**
* Returns last error reported by database engine.
* @return string error message
*/
public function get_last_error() {
return $this->mysqli->error;
}
/**
* Return tables in database WITHOUT current prefix
* @param bool $usecache if true, returns list of cached tables.
* @return array of table names in lowercase and without prefix
*/
public function get_tables($usecache=true) {
if ($usecache and $this->tables !== null) {
return $this->tables;
}
$this->tables = array();
$prefix = str_replace('_', '\\_', $this->prefix);
$sql = "SHOW TABLES LIKE '$prefix%'";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
$len = strlen($this->prefix);
if ($result) {
while ($arr = $result->fetch_assoc()) {
$tablename = reset($arr);
$tablename = substr($tablename, $len);
$this->tables[$tablename] = $tablename;
}
$result->close();
}
// Add the currently available temptables
$this->tables = array_merge($this->tables, $this->temptables->get_temptables());
return $this->tables;
}
/**
* Return table indexes - everything lowercased.
* @param string $table The table we want to get indexes from.
* @return array An associative array of indexes containing 'unique' flag and 'columns' being indexed
*/
public function get_indexes($table) {
$indexes = array();
$sql = "SHOW INDEXES FROM {$this->prefix}$table";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
try {
$this->query_end($result);
} catch (dml_read_exception $e) {
return $indexes; // table does not exist - no indexes...
}
if ($result) {
while ($res = $result->fetch_object()) {
if ($res->Key_name === 'PRIMARY') {
continue;
}
if (!isset($indexes[$res->Key_name])) {
$indexes[$res->Key_name] = array('unique'=>empty($res->Non_unique), 'columns'=>array());
}
$indexes[$res->Key_name]['columns'][$res->Seq_in_index-1] = $res->Column_name;
}
$result->close();
}
return $indexes;
}
/**
* Returns detailed information about columns in table. This information is cached internally.
* @param string $table name
* @param bool $usecache
* @return database_column_info[] array of database_column_info objects indexed with column names
*/
public function get_columns($table, $usecache=true) {
if ($usecache) {
if ($this->temptables->is_temptable($table)) {
if ($data = $this->get_temp_tables_cache()->get($table)) {
return $data;
}
} else {
if ($data = $this->get_metacache()->get($table)) {
return $data;
}
}
}
$structure = array();
$sql = "SELECT column_name, data_type, character_maximum_length, numeric_precision,
numeric_scale, is_nullable, column_type, column_default, column_key, extra
FROM information_schema.columns
WHERE table_name = '" . $this->prefix.$table . "'
AND table_schema = '" . $this->dbname . "'
ORDER BY ordinal_position";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end(true); // Don't want to throw anything here ever. MDL-30147
if ($result === false) {
return array();
}
if ($result->num_rows > 0) {
// standard table exists
while ($rawcolumn = $result->fetch_assoc()) {
// MySQL 8 BC: information_schema.* returns the fields in upper case.
$rawcolumn = array_change_key_case($rawcolumn, CASE_LOWER);
$info = (object)$this->get_column_info((object)$rawcolumn);
$structure[$info->name] = new database_column_info($info);
}
$result->close();
} else {
// temporary tables are not in information schema, let's try it the old way
$result->close();
$sql = "SHOW COLUMNS FROM {$this->prefix}$table";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end(true);
if ($result === false) {
return array();
}
while ($rawcolumn = $result->fetch_assoc()) {
$rawcolumn = (object)array_change_key_case($rawcolumn, CASE_LOWER);
$rawcolumn->column_name = $rawcolumn->field; unset($rawcolumn->field);
$rawcolumn->column_type = $rawcolumn->type; unset($rawcolumn->type);
$rawcolumn->character_maximum_length = null;
$rawcolumn->numeric_precision = null;
$rawcolumn->numeric_scale = null;
$rawcolumn->is_nullable = $rawcolumn->null; unset($rawcolumn->null);
$rawcolumn->column_default = $rawcolumn->default; unset($rawcolumn->default);
$rawcolumn->column_key = $rawcolumn->key; unset($rawcolumn->key);
if (preg_match('/(enum|varchar)\((\d+)\)/i', $rawcolumn->column_type, $matches)) {
$rawcolumn->data_type = $matches[1];
$rawcolumn->character_maximum_length = $matches[2];
} else if (preg_match('/([a-z]*int[a-z]*)\((\d+)\)/i', $rawcolumn->column_type, $matches)) {
$rawcolumn->data_type = $matches[1];
$rawcolumn->numeric_precision = $matches[2];
$rawcolumn->max_length = $rawcolumn->numeric_precision;
$type = strtoupper($matches[1]);
if ($type === 'BIGINT') {
$maxlength = 18;
} else if ($type === 'INT' or $type === 'INTEGER') {
$maxlength = 9;
} else if ($type === 'MEDIUMINT') {
$maxlength = 6;
} else if ($type === 'SMALLINT') {
$maxlength = 4;
} else if ($type === 'TINYINT') {
$maxlength = 2;
} else {
// This should not happen.
$maxlength = 0;
}
if ($maxlength < $rawcolumn->max_length) {
$rawcolumn->max_length = $maxlength;
}
} else if (preg_match('/(decimal)\((\d+),(\d+)\)/i', $rawcolumn->column_type, $matches)) {
$rawcolumn->data_type = $matches[1];
$rawcolumn->numeric_precision = $matches[2];
$rawcolumn->numeric_scale = $matches[3];
} else if (preg_match('/(double|float)(\((\d+),(\d+)\))?/i', $rawcolumn->column_type, $matches)) {
$rawcolumn->data_type = $matches[1];
$rawcolumn->numeric_precision = isset($matches[3]) ? $matches[3] : null;
$rawcolumn->numeric_scale = isset($matches[4]) ? $matches[4] : null;
} else if (preg_match('/([a-z]*text)/i', $rawcolumn->column_type, $matches)) {
$rawcolumn->data_type = $matches[1];
$rawcolumn->character_maximum_length = -1; // unknown
} else if (preg_match('/([a-z]*blob)/i', $rawcolumn->column_type, $matches)) {
$rawcolumn->data_type = $matches[1];
} else {
$rawcolumn->data_type = $rawcolumn->column_type;
}
$info = $this->get_column_info($rawcolumn);
$structure[$info->name] = new database_column_info($info);
}
$result->close();
}
if ($usecache) {
if ($this->temptables->is_temptable($table)) {
$this->get_temp_tables_cache()->set($table, $structure);
} else {
$this->get_metacache()->set($table, $structure);
}
}
return $structure;
}
/**
* Indicates whether column information retrieved from `information_schema.columns` has default values quoted or not.
* @return boolean True when default values are quoted (breaking change); otherwise, false.
*/
protected function has_breaking_change_quoted_defaults() {
return false;
}
/**
* Indicates whether SQL_MODE default value has changed in a not backward compatible way.
* @return boolean True when SQL_MODE breaks BC; otherwise, false.
*/
public function has_breaking_change_sqlmode() {
return false;
}
/**
* Returns moodle column info for raw column from information schema.
* @param stdClass $rawcolumn
* @return stdClass standardised colum info
*/
private function get_column_info(stdClass $rawcolumn) {
$rawcolumn = (object)$rawcolumn;
$info = new stdClass();
$info->name = $rawcolumn->column_name;
$info->type = $rawcolumn->data_type;
$info->meta_type = $this->mysqltype2moodletype($rawcolumn->data_type);
if ($this->has_breaking_change_quoted_defaults()) {
$info->default_value = trim($rawcolumn->column_default, "'");
if ($info->default_value === 'NULL') {
$info->default_value = null;
}
} else {
$info->default_value = $rawcolumn->column_default;
}
$info->has_default = !is_null($info->default_value);
$info->not_null = ($rawcolumn->is_nullable === 'NO');
$info->primary_key = ($rawcolumn->column_key === 'PRI');
$info->binary = false;
$info->unsigned = null;
$info->auto_increment = false;
$info->unique = null;
$info->scale = null;
if ($info->meta_type === 'C') {
$info->max_length = $rawcolumn->character_maximum_length;
} else if ($info->meta_type === 'I') {
if ($info->primary_key) {
$info->meta_type = 'R';
$info->unique = true;
}
// Return number of decimals, not bytes here.
$info->max_length = $rawcolumn->numeric_precision;
if (preg_match('/([a-z]*int[a-z]*)\((\d+)\)/i', $rawcolumn->column_type, $matches)) {
$type = strtoupper($matches[1]);
if ($type === 'BIGINT') {
$maxlength = 18;
} else if ($type === 'INT' or $type === 'INTEGER') {
$maxlength = 9;
} else if ($type === 'MEDIUMINT') {
$maxlength = 6;
} else if ($type === 'SMALLINT') {
$maxlength = 4;
} else if ($type === 'TINYINT') {
$maxlength = 2;
} else {
// This should not happen.
$maxlength = 0;
}
// It is possible that display precision is different from storage type length,
// always use the smaller value to make sure our data fits.
if ($maxlength < $info->max_length) {
$info->max_length = $maxlength;
}
}
$info->unsigned = (stripos($rawcolumn->column_type, 'unsigned') !== false);
$info->auto_increment= (strpos($rawcolumn->extra, 'auto_increment') !== false);
} else if ($info->meta_type === 'N') {
$info->max_length = $rawcolumn->numeric_precision;
$info->scale = $rawcolumn->numeric_scale;
$info->unsigned = (stripos($rawcolumn->column_type, 'unsigned') !== false);
} else if ($info->meta_type === 'X') {
if ("$rawcolumn->character_maximum_length" === '4294967295') { // watch out for PHP max int limits!
// means maximum moodle size for text column, in other drivers it may also mean unknown size
$info->max_length = -1;
} else {
$info->max_length = $rawcolumn->character_maximum_length;
}
$info->primary_key = false;
} else if ($info->meta_type === 'B') {
$info->max_length = -1;
$info->primary_key = false;
$info->binary = true;
}
return $info;
}
/**
* Normalise column type.
* @param string $mysql_type
* @return string one character
* @throws dml_exception
*/
private function mysqltype2moodletype($mysql_type) {
$type = null;
switch(strtoupper($mysql_type)) {
case 'BIT':
$type = 'L';
break;
case 'TINYINT':
case 'SMALLINT':
case 'MEDIUMINT':
case 'INT':
case 'INTEGER':
case 'BIGINT':
$type = 'I';
break;
case 'FLOAT':
case 'DOUBLE':
case 'DECIMAL':
$type = 'N';
break;
case 'CHAR':
case 'ENUM':
case 'SET':
case 'VARCHAR':
$type = 'C';
break;
case 'TINYTEXT':
case 'TEXT':
case 'MEDIUMTEXT':
case 'LONGTEXT':
$type = 'X';
break;
case 'BINARY':
case 'VARBINARY':
case 'BLOB':
case 'TINYBLOB':
case 'MEDIUMBLOB':
case 'LONGBLOB':
$type = 'B';
break;
case 'DATE':
case 'TIME':
case 'DATETIME':
case 'TIMESTAMP':
case 'YEAR':
$type = 'D';
break;
}
if (!$type) {
throw new dml_exception('invalidmysqlnativetype', $mysql_type);
}
return $type;
}
/**
* Normalise values based in RDBMS dependencies (booleans, LOBs...)
*
* @param database_column_info $column column metadata corresponding with the value we are going to normalise
* @param mixed $value value we are going to normalise
* @return mixed the normalised value
*/
protected function normalise_value($column, $value) {
$this->detect_objects($value);
if (is_bool($value)) { // Always, convert boolean to int
$value = (int)$value;
} else if ($value === '') {
if ($column->meta_type == 'I' or $column->meta_type == 'F' or $column->meta_type == 'N') {
$value = 0; // prevent '' problems in numeric fields
}
// Any float value being stored in varchar or text field is converted to string to avoid
// any implicit conversion by MySQL
} else if (is_float($value) and ($column->meta_type == 'C' or $column->meta_type == 'X')) {
$value = "$value";
}
return $value;
}
/**
* Is this database compatible with utf8?
* @return bool
*/
public function setup_is_unicodedb() {
// All new tables are created with this collation, we just have to make sure it is utf8 compatible,
// if config table already exists it has this collation too.
$collation = $this->get_dbcollation();
$collationinfo = explode('_', $collation);
$charset = reset($collationinfo);
$sql = "SHOW COLLATION WHERE Collation ='$collation' AND Charset = '$charset'";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($result->fetch_assoc()) {
$return = true;
} else {
$return = false;
}
$result->close();
return $return;
}
/**
* Do NOT use in code, to be used by database_manager only!
* @param string|array $sql query
* @param array|null $tablenames an array of xmldb table names affected by this request.
* @return bool true
* @throws ddl_change_structure_exception A DDL specific exception is thrown for any errors.
*/
public function change_database_structure($sql, $tablenames = null) {
$this->get_manager(); // Includes DDL exceptions classes ;-)
if (is_array($sql)) {
$sql = implode("\n;\n", $sql);
}
try {
$this->query_start($sql, null, SQL_QUERY_STRUCTURE);
$result = $this->mysqli->multi_query($sql);
if ($result === false) {
$this->query_end(false);
}
while ($this->mysqli->more_results()) {
$result = $this->mysqli->next_result();
if ($result === false) {
$this->query_end(false);
}
}
$this->query_end(true);
} catch (ddl_change_structure_exception $e) {
while (@$this->mysqli->more_results()) {
@$this->mysqli->next_result();
}
$this->reset_caches($tablenames);
throw $e;
}
$this->reset_caches($tablenames);
return true;
}
/**
* Very ugly hack which emulates bound parameters in queries
* because prepared statements do not use query cache.
*/
protected function emulate_bound_params($sql, array $params=null) {
if (empty($params)) {
return $sql;
}
// ok, we have verified sql statement with ? and correct number of params
$parts = array_reverse(explode('?', $sql));
$return = array_pop($parts);
foreach ($params as $param) {
if (is_bool($param)) {
$return .= (int)$param;
} else if (is_null($param)) {
$return .= 'NULL';
} else if (is_number($param)) {
$return .= "'".$param."'"; // we have to always use strings because mysql is using weird automatic int casting
} else if (is_float($param)) {
$return .= $param;
} else {
$param = $this->mysqli->real_escape_string($param);
$return .= "'$param'";
}
$return .= array_pop($parts);
}
return $return;
}
/**
* Execute general sql query. Should be used only when no other method suitable.
* Do NOT use this to make changes in db structure, use database_manager methods instead!
* @param string $sql query
* @param array $params query parameters
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function execute($sql, array $params=null) {
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
if (strpos($sql, ';') !== false) {
throw new coding_exception('moodle_database::execute() Multiple sql statements found or bound parameters not used properly in query!');
}
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_UPDATE);
$result = $this->mysqli->query($rawsql);
$this->query_end($result);
if ($result === true) {
return true;
} else {
$result->close();
return true;
}
}
/**
* Get a number of records as a moodle_recordset using a SQL statement.
*
* Since this method is a little less readable, use of it should be restricted to
* code where it's possible there might be large datasets being returned. For known
* small datasets use get_records_sql - it leads to simpler code.
*
* The return type is like:
* @see function get_recordset.
*
* @param string $sql the SQL select query to execute.
* @param array $params array of sql parameters
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return moodle_recordset instance
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_recordset_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) {
list($limitfrom, $limitnum) = $this->normalise_limit_from_num($limitfrom, $limitnum);
if ($limitfrom or $limitnum) {
if ($limitnum < 1) {
$limitnum = "18446744073709551615";
}
$sql .= " LIMIT $limitfrom, $limitnum";
}
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_SELECT);
// no MYSQLI_USE_RESULT here, it would block write ops on affected tables
$result = $this->mysqli->query($rawsql, MYSQLI_STORE_RESULT);
$this->query_end($result);
return $this->create_recordset($result);
}
/**
* Get all records from a table.
*
* This method works around potential memory problems and may improve performance,
* this method may block access to table until the recordset is closed.
*
* @param string $table Name of database table.
* @return moodle_recordset A moodle_recordset instance {@link function get_recordset}.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function export_table_recordset($table) {
$sql = $this->fix_table_names("SELECT * FROM {{$table}}");
$this->query_start($sql, array(), SQL_QUERY_SELECT);
// MYSQLI_STORE_RESULT may eat all memory for large tables, unfortunately MYSQLI_USE_RESULT blocks other queries.
$result = $this->mysqli->query($sql, MYSQLI_USE_RESULT);
$this->query_end($result);
return $this->create_recordset($result);
}
protected function create_recordset($result) {
return new mysqli_native_moodle_recordset($result);
}
/**
* Get a number of records as an array of objects using a SQL statement.
*
* Return value is like:
* @see function get_records.
*
* @param string $sql the SQL select query to execute. The first column of this SELECT statement
* must be a unique value (usually the 'id' field), as it will be used as the key of the
* returned array.
* @param array $params array of sql parameters
* @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return array of objects, or empty array if no records were found
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_records_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) {
list($limitfrom, $limitnum) = $this->normalise_limit_from_num($limitfrom, $limitnum);
if ($limitfrom or $limitnum) {
if ($limitnum < 1) {
$limitnum = "18446744073709551615";
}
$sql .= " LIMIT $limitfrom, $limitnum";
}
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_SELECT);
$result = $this->mysqli->query($rawsql, MYSQLI_STORE_RESULT);
$this->query_end($result);
$return = array();
while($row = $result->fetch_assoc()) {
$row = array_change_key_case($row, CASE_LOWER);
$id = reset($row);
if (isset($return[$id])) {
$colname = key($row);
debugging("Did you remember to make the first column something unique in your call to get_records? Duplicate value '$id' found in column '$colname'.", DEBUG_DEVELOPER);
}
$return[$id] = (object)$row;
}
$result->close();
return $return;
}
/**
* Selects records and return values (first field) as an array using a SQL statement.
*
* @param string $sql The SQL query
* @param array $params array of sql parameters
* @return array of values
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_fieldset_sql($sql, array $params=null) {
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_SELECT);
$result = $this->mysqli->query($rawsql, MYSQLI_STORE_RESULT);
$this->query_end($result);
$return = array();
while($row = $result->fetch_assoc()) {
$return[] = reset($row);
}
$result->close();
return $return;
}
/**
* Insert new record into database, as fast as possible, no safety checks, lobs not supported.
* @param string $table name
* @param mixed $params data record as object or array
* @param bool $returnit return it of inserted record
* @param bool $bulk true means repeated inserts expected
* @param bool $customsequence true if 'id' included in $params, disables $returnid
* @return bool|int true or new id
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function insert_record_raw($table, $params, $returnid=true, $bulk=false, $customsequence=false) {
if (!is_array($params)) {
$params = (array)$params;
}
if ($customsequence) {
if (!isset($params['id'])) {
throw new coding_exception('moodle_database::insert_record_raw() id field must be specified if custom sequences used.');
}
$returnid = false;
} else {
unset($params['id']);
}
if (empty($params)) {
throw new coding_exception('moodle_database::insert_record_raw() no fields found.');
}
$fields = implode(',', array_keys($params));
$qms = array_fill(0, count($params), '?');
$qms = implode(',', $qms);
$sql = "INSERT INTO {$this->prefix}$table ($fields) VALUES($qms)";
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_INSERT);
$result = $this->mysqli->query($rawsql);
$id = @$this->mysqli->insert_id; // must be called before query_end() which may insert log into db
$this->query_end($result);
if (!$customsequence and !$id) {
throw new dml_write_exception('unknown error fetching inserted id');
}
if (!$returnid) {
return true;
} else {
return (int)$id;
}
}
/**
* Insert a record into a table and return the "id" field if required.
*
* Some conversions and safety checks are carried out. Lobs are supported.
* If the return ID isn't required, then this just reports success as true/false.
* $data is an object containing needed data
* @param string $table The database table to be inserted into
* @param object $data A data object with values for one or more fields in the record
* @param bool $returnid Should the id of the newly created record entry be returned? If this option is not requested then true/false is returned.
* @return bool|int true or new id
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function insert_record($table, $dataobject, $returnid=true, $bulk=false) {
$dataobject = (array)$dataobject;
$columns = $this->get_columns($table);
if (empty($columns)) {
throw new dml_exception('ddltablenotexist', $table);
}
$cleaned = array();
foreach ($dataobject as $field=>$value) {
if ($field === 'id') {
continue;
}
if (!isset($columns[$field])) {
continue;
}
$column = $columns[$field];
$cleaned[$field] = $this->normalise_value($column, $value);
}
return $this->insert_record_raw($table, $cleaned, $returnid, $bulk);
}
/**
* Insert multiple records into database as fast as possible.
*
* Order of inserts is maintained, but the operation is not atomic,
* use transactions if necessary.
*
* This method is intended for inserting of large number of small objects,
* do not use for huge objects with text or binary fields.
*
* @since Moodle 2.7
*
* @param string $table The database table to be inserted into
* @param array|Traversable $dataobjects list of objects to be inserted, must be compatible with foreach
* @return void does not return new record ids
*
* @throws coding_exception if data objects have different structure
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function insert_records($table, $dataobjects) {
if (!is_array($dataobjects) and !$dataobjects instanceof Traversable) {
throw new coding_exception('insert_records() passed non-traversable object');
}
// MySQL has a relatively small query length limit by default,
// make sure 'max_allowed_packet' in my.cnf is high enough
// if you change the following default...
static $chunksize = null;
if ($chunksize === null) {
if (!empty($this->dboptions['bulkinsertsize'])) {
$chunksize = (int)$this->dboptions['bulkinsertsize'];
} else {
if (PHP_INT_SIZE === 4) {
// Bad luck for Windows, we cannot do any maths with large numbers.
$chunksize = 5;
} else {
$sql = "SHOW VARIABLES LIKE 'max_allowed_packet'";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
$size = 0;
if ($rec = $result->fetch_assoc()) {
$size = $rec['Value'];
}
$result->close();
// Hopefully 200kb per object are enough.
$chunksize = (int)($size / 200000);
if ($chunksize > 50) {
$chunksize = 50;
}
}
}
}
$columns = $this->get_columns($table, true);
$fields = null;
$count = 0;
$chunk = array();
foreach ($dataobjects as $dataobject) {
if (!is_array($dataobject) and !is_object($dataobject)) {
throw new coding_exception('insert_records() passed invalid record object');
}
$dataobject = (array)$dataobject;
if ($fields === null) {
$fields = array_keys($dataobject);
$columns = array_intersect_key($columns, $dataobject);
unset($columns['id']);
} else if ($fields !== array_keys($dataobject)) {
throw new coding_exception('All dataobjects in insert_records() must have the same structure!');
}
$count++;
$chunk[] = $dataobject;
if ($count === $chunksize) {
$this->insert_chunk($table, $chunk, $columns);
$chunk = array();
$count = 0;
}
}
if ($count) {
$this->insert_chunk($table, $chunk, $columns);
}
}
/**
* Insert records in chunks.
*
* Note: can be used only from insert_records().
*
* @param string $table
* @param array $chunk
* @param database_column_info[] $columns
*/
protected function insert_chunk($table, array $chunk, array $columns) {
$fieldssql = '('.implode(',', array_keys($columns)).')';
$valuessql = '('.implode(',', array_fill(0, count($columns), '?')).')';
$valuessql = implode(',', array_fill(0, count($chunk), $valuessql));
$params = array();
foreach ($chunk as $dataobject) {
foreach ($columns as $field => $column) {
$params[] = $this->normalise_value($column, $dataobject[$field]);
}
}
$sql = "INSERT INTO {$this->prefix}$table $fieldssql VALUES $valuessql";
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_INSERT);
$result = $this->mysqli->query($rawsql);
$this->query_end($result);
}
/**
* Import a record into a table, id field is required.
* Safety checks are NOT carried out. Lobs are supported.
*
* @param string $table name of database table to be inserted into
* @param object $dataobject A data object with values for one or more fields in the record
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function import_record($table, $dataobject) {
$dataobject = (array)$dataobject;
$columns = $this->get_columns($table);
$cleaned = array();
foreach ($dataobject as $field=>$value) {
if (!isset($columns[$field])) {
continue;
}
$cleaned[$field] = $value;
}
return $this->insert_record_raw($table, $cleaned, false, true, true);
}
/**
* Update record in database, as fast as possible, no safety checks, lobs not supported.
* @param string $table name
* @param mixed $params data record as object or array
* @param bool true means repeated updates expected
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function update_record_raw($table, $params, $bulk=false) {
$params = (array)$params;
if (!isset($params['id'])) {
throw new coding_exception('moodle_database::update_record_raw() id field must be specified.');
}
$id = $params['id'];
unset($params['id']);
if (empty($params)) {
throw new coding_exception('moodle_database::update_record_raw() no fields found.');
}
$sets = array();
foreach ($params as $field=>$value) {
$sets[] = "$field = ?";
}
$params[] = $id; // last ? in WHERE condition
$sets = implode(',', $sets);
$sql = "UPDATE {$this->prefix}$table SET $sets WHERE id=?";
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_UPDATE);
$result = $this->mysqli->query($rawsql);
$this->query_end($result);
return true;
}
/**
* Update a record in a table
*
* $dataobject is an object containing needed data
* Relies on $dataobject having a variable "id" to
* specify the record to update
*
* @param string $table The database table to be checked against.
* @param object $dataobject An object with contents equal to fieldname=>fieldvalue. Must have an entry for 'id' to map to the table specified.
* @param bool true means repeated updates expected
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function update_record($table, $dataobject, $bulk=false) {
$dataobject = (array)$dataobject;
$columns = $this->get_columns($table);
$cleaned = array();
foreach ($dataobject as $field=>$value) {
if (!isset($columns[$field])) {
continue;
}
$column = $columns[$field];
$cleaned[$field] = $this->normalise_value($column, $value);
}
return $this->update_record_raw($table, $cleaned, $bulk);
}
/**
* Set a single field in every table record which match a particular WHERE clause.
*
* @param string $table The database table to be checked against.
* @param string $newfield the field to set.
* @param string $newvalue the value to set the field to.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call.
* @param array $params array of sql parameters
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function set_field_select($table, $newfield, $newvalue, $select, array $params=null) {
if ($select) {
$select = "WHERE $select";
}
if (is_null($params)) {
$params = array();
}
list($select, $params, $type) = $this->fix_sql_params($select, $params);
// Get column metadata
$columns = $this->get_columns($table);
$column = $columns[$newfield];
$normalised_value = $this->normalise_value($column, $newvalue);
if (is_null($normalised_value)) {
$newfield = "$newfield = NULL";
} else {
$newfield = "$newfield = ?";
array_unshift($params, $normalised_value);
}
$sql = "UPDATE {$this->prefix}$table SET $newfield $select";
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_UPDATE);
$result = $this->mysqli->query($rawsql);
$this->query_end($result);
return true;
}
/**
* Delete one or more records from a table which match a particular WHERE clause.
*
* @param string $table The database table to be checked against.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call (used to define the selection criteria).
* @param array $params array of sql parameters
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function delete_records_select($table, $select, array $params=null) {
if ($select) {
$select = "WHERE $select";
}
$sql = "DELETE FROM {$this->prefix}$table $select";
list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
$rawsql = $this->emulate_bound_params($sql, $params);
$this->query_start($sql, $params, SQL_QUERY_UPDATE);
$result = $this->mysqli->query($rawsql);
$this->query_end($result);
return true;
}
public function sql_cast_char2int($fieldname, $text=false) {
return ' CAST(' . $fieldname . ' AS SIGNED) ';
}
public function sql_cast_char2real($fieldname, $text=false) {
// Set to 65 (max mysql 5.5 precision) with 7 as scale
// because we must ensure at least 6 decimal positions
// per casting given that postgres is casting to that scale (::real::).
// Can be raised easily but that must be done in all DBs and tests.
return ' CAST(' . $fieldname . ' AS DECIMAL(65,7)) ';
}
public function sql_equal($fieldname, $param, $casesensitive = true, $accentsensitive = true, $notequal = false) {
$equalop = $notequal ? '<>' : '=';
$collationinfo = explode('_', $this->get_dbcollation());
$bincollate = reset($collationinfo) . '_bin';
if ($casesensitive) {
// Current MySQL versions do not support case sensitive and accent insensitive.
return "$fieldname COLLATE $bincollate $equalop $param";
} else if ($accentsensitive) {
// Case insensitive and accent sensitive, we can force a binary comparison once all texts are using the same case.
return "LOWER($fieldname) COLLATE $bincollate $equalop LOWER($param)";
} else {
// Case insensitive and accent insensitive. All collations are that way, but utf8_bin.
$collation = '';
if ($this->get_dbcollation() == 'utf8_bin') {
$collation = 'COLLATE utf8_unicode_ci';
} else if ($this->get_dbcollation() == 'utf8mb4_bin') {
$collation = 'COLLATE utf8mb4_unicode_ci';
}
return "$fieldname $collation $equalop $param";
}
}
/**
* Returns 'LIKE' part of a query.
*
* Note that mysql does not support $casesensitive = true and $accentsensitive = false.
* More information in http://bugs.mysql.com/bug.php?id=19567.
*
* @param string $fieldname usually name of the table column
* @param string $param usually bound query parameter (?, :named)
* @param bool $casesensitive use case sensitive search
* @param bool $accensensitive use accent sensitive search (ignored if $casesensitive is true)
* @param bool $notlike true means "NOT LIKE"
* @param string $escapechar escape char for '%' and '_'
* @return string SQL code fragment
*/
public function sql_like($fieldname, $param, $casesensitive = true, $accentsensitive = true, $notlike = false, $escapechar = '\\') {
if (strpos($param, '%') !== false) {
debugging('Potential SQL injection detected, sql_like() expects bound parameters (? or :named)');
}
$escapechar = $this->mysqli->real_escape_string($escapechar); // prevents problems with C-style escapes of enclosing '\'
$collationinfo = explode('_', $this->get_dbcollation());
$bincollate = reset($collationinfo) . '_bin';
$LIKE = $notlike ? 'NOT LIKE' : 'LIKE';
if ($casesensitive) {
// Current MySQL versions do not support case sensitive and accent insensitive.
return "$fieldname $LIKE $param COLLATE $bincollate ESCAPE '$escapechar'";
} else if ($accentsensitive) {
// Case insensitive and accent sensitive, we can force a binary comparison once all texts are using the same case.
return "LOWER($fieldname) $LIKE LOWER($param) COLLATE $bincollate ESCAPE '$escapechar'";
} else {
// Case insensitive and accent insensitive.
$collation = '';
if ($this->get_dbcollation() == 'utf8_bin') {
// Force a case insensitive comparison if using utf8_bin.
$collation = 'COLLATE utf8_unicode_ci';
} else if ($this->get_dbcollation() == 'utf8mb4_bin') {
// Force a case insensitive comparison if using utf8mb4_bin.
$collation = 'COLLATE utf8mb4_unicode_ci';
}
return "$fieldname $LIKE $param $collation ESCAPE '$escapechar'";
}
}
/**
* Returns the proper SQL to do CONCAT between the elements passed
* Can take many parameters
*
* @param string $str,... 1 or more fields/strings to concat
*
* @return string The concat sql
*/
public function sql_concat() {
$arr = func_get_args();
$s = implode(', ', $arr);
if ($s === '') {
return "''";
}
return "CONCAT($s)";
}
/**
* Returns the proper SQL to do CONCAT between the elements passed
* with a given separator
*
* @param string $separator The string to use as the separator
* @param array $elements An array of items to concatenate
* @return string The concat SQL
*/
public function sql_concat_join($separator="' '", $elements=array()) {
$s = implode(', ', $elements);
if ($s === '') {
return "''";
}
return "CONCAT_WS($separator, $s)";
}
/**
* Returns the SQL text to be used to calculate the length in characters of one expression.
* @param string fieldname or expression to calculate its length in characters.
* @return string the piece of SQL code to be used in the statement.
*/
public function sql_length($fieldname) {
return ' CHAR_LENGTH(' . $fieldname . ')';
}
/**
* Does this driver support regex syntax when searching
*/
public function sql_regex_supported() {
return true;
}
/**
* Return regex positive or negative match sql
* @param bool $positivematch
* @param bool $casesensitive
* @return string or empty if not supported
*/
public function sql_regex($positivematch = true, $casesensitive = false) {
$collation = '';
if ($casesensitive) {
if (substr($this->get_dbcollation(), -4) !== '_bin') {
$collationinfo = explode('_', $this->get_dbcollation());
$collation = 'COLLATE ' . $collationinfo[0] . '_bin ';
}
} else {
if ($this->get_dbcollation() == 'utf8_bin') {
$collation = 'COLLATE utf8_unicode_ci ';
} else if ($this->get_dbcollation() == 'utf8mb4_bin') {
$collation = 'COLLATE utf8mb4_unicode_ci ';
}
}
return $collation . ($positivematch ? 'REGEXP' : 'NOT REGEXP');
}
/**
* Returns the SQL to be used in order to an UNSIGNED INTEGER column to SIGNED.
*
* @deprecated since 2.3
* @param string $fieldname The name of the field to be cast
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_cast_2signed($fieldname) {
return ' CAST(' . $fieldname . ' AS SIGNED) ';
}
/**
* Returns the SQL that allows to find intersection of two or more queries
*
* @since Moodle 2.8
*
* @param array $selects array of SQL select queries, each of them only returns fields with the names from $fields
* @param string $fields comma-separated list of fields
* @return string SQL query that will return only values that are present in each of selects
*/
public function sql_intersect($selects, $fields) {
if (count($selects) <= 1) {
return parent::sql_intersect($selects, $fields);
}
$fields = preg_replace('/\s/', '', $fields);
static $aliascnt = 0;
$falias = 'intsctal'.($aliascnt++);
$rv = "SELECT $falias.".
preg_replace('/,/', ','.$falias.'.', $fields).
" FROM ($selects[0]) $falias";
for ($i = 1; $i < count($selects); $i++) {
$alias = 'intsctal'.($aliascnt++);
$rv .= " JOIN (".$selects[$i].") $alias ON ".
join(' AND ',
array_map(
function($a) use ($alias, $falias) {
return $falias . '.' . $a .' = ' . $alias . '.' . $a;
},
preg_split('/,/', $fields))
);
}
return $rv;
}
/**
* Does this driver support tool_replace?
*
* @since Moodle 2.6.1
* @return bool
*/
public function replace_all_text_supported() {
return true;
}
public function session_lock_supported() {
return true;
}
/**
* Obtain session lock
* @param int $rowid id of the row with session record
* @param int $timeout max allowed time to wait for the lock in seconds
* @return void
*/
public function get_session_lock($rowid, $timeout) {
parent::get_session_lock($rowid, $timeout);
$fullname = $this->dbname.'-'.$this->prefix.'-session-'.$rowid;
$sql = "SELECT GET_LOCK('$fullname', $timeout)";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($result) {
$arr = $result->fetch_assoc();
$result->close();
if (reset($arr) == 1) {
return;
} else {
throw new dml_sessionwait_exception();
}
}
}
public function release_session_lock($rowid) {
if (!$this->used_for_db_sessions) {
return;
}
parent::release_session_lock($rowid);
$fullname = $this->dbname.'-'.$this->prefix.'-session-'.$rowid;
$sql = "SELECT RELEASE_LOCK('$fullname')";
$this->query_start($sql, null, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
if ($result) {
$result->close();
}
}
/**
* Are transactions supported?
* It is not responsible to run productions servers
* on databases without transaction support ;-)
*
* MyISAM does not support support transactions.
*
* You can override this via the dbtransactions option.
*
* @return bool
*/
protected function transactions_supported() {
if (!is_null($this->transactions_supported)) {
return $this->transactions_supported;
}
// this is all just guessing, might be better to just specify it in config.php
if (isset($this->dboptions['dbtransactions'])) {
$this->transactions_supported = $this->dboptions['dbtransactions'];
return $this->transactions_supported;
}
$this->transactions_supported = false;
$engine = $this->get_dbengine();
// Only will accept transactions if using compatible storage engine (more engines can be added easily BDB, Falcon...)
if (in_array($engine, array('InnoDB', 'INNOBASE', 'BDB', 'XtraDB', 'Aria', 'Falcon'))) {
$this->transactions_supported = true;
}
return $this->transactions_supported;
}
/**
* Driver specific start of real database transaction,
* this can not be used directly in code.
* @return void
*/
protected function begin_transaction() {
if (!$this->transactions_supported()) {
return;
}
$sql = "SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
$sql = "START TRANSACTION";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
}
/**
* Driver specific commit of real database transaction,
* this can not be used directly in code.
* @return void
*/
protected function commit_transaction() {
if (!$this->transactions_supported()) {
return;
}
$sql = "COMMIT";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
}
/**
* Driver specific abort of real database transaction,
* this can not be used directly in code.
* @return void
*/
protected function rollback_transaction() {
if (!$this->transactions_supported()) {
return;
}
$sql = "ROLLBACK";
$this->query_start($sql, NULL, SQL_QUERY_AUX);
$result = $this->mysqli->query($sql);
$this->query_end($result);
return true;
}
/**
* Converts a table to either 'Compressed' or 'Dynamic' row format.
*
* @param string $tablename Name of the table to convert to the new row format.
*/
public function convert_table_row_format($tablename) {
$currentrowformat = $this->get_row_format($tablename);
if ($currentrowformat == 'Compact' || $currentrowformat == 'Redundant') {
$rowformat = ($this->is_compressed_row_format_supported(false)) ? "ROW_FORMAT=Compressed" : "ROW_FORMAT=Dynamic";
$prefix = $this->get_prefix();
$this->change_database_structure("ALTER TABLE {$prefix}$tablename $rowformat");
}
}
/**
* Does this mysql instance support fulltext indexes?
*
* @return bool
*/
public function is_fulltext_search_supported() {
$info = $this->get_server_info();
if (version_compare($info['version'], '5.6.4', '>=')) {
return true;
}
return false;
}
}