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- Bug fixes for general core bugs in 4.2.x will end 22 April 2024 (12 months).
- Bug fixes for security issues in 4.2.x will end 7 October 2024 (18 months).
- PHP version: minimum PHP 8.0.0 Note: minimum PHP version has increased since Moodle 4.1. PHP 8.1.x is supported too.
/lib/dml/ -> moodle_database.php (source)
<?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/>.
/**
* Abstract database driver class.
*
* @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__.'/database_column_info.php');
require_once(__DIR__.'/moodle_recordset.php');
require_once(__DIR__.'/moodle_transaction.php');
/** SQL_PARAMS_NAMED - Bitmask, indicates :name type parameters are supported by db backend. */
define('SQL_PARAMS_NAMED', 1);
/** SQL_PARAMS_QM - Bitmask, indicates ? type parameters are supported by db backend. */
define('SQL_PARAMS_QM', 2);
/** SQL_PARAMS_DOLLAR - Bitmask, indicates $1, $2, ... type parameters are supported by db backend. */
define('SQL_PARAMS_DOLLAR', 4);
/** SQL_QUERY_SELECT - Normal select query, reading only. */
define('SQL_QUERY_SELECT', 1);
/** SQL_QUERY_INSERT - Insert select query, writing. */
define('SQL_QUERY_INSERT', 2);
/** SQL_QUERY_UPDATE - Update select query, writing. */
define('SQL_QUERY_UPDATE', 3);
/** SQL_QUERY_STRUCTURE - Query changing db structure, writing. */
define('SQL_QUERY_STRUCTURE', 4);
/** SQL_QUERY_AUX - Auxiliary query done by driver, setting connection config, getting table info, etc. */
define('SQL_QUERY_AUX', 5);
/** SQL_QUERY_AUX_READONLY - Auxiliary query that can be done using the readonly connection:
* database parameters, table/index/column lists, if not within transaction/ddl. */
define('SQL_QUERY_AUX_READONLY', 6);
/**
* Abstract class representing moodle database interface.
* @link https://moodledev.io/docs/apis/core/dml/ddl
*
* @package core_dml
* @copyright 2008 Petr Skoda (http://skodak.org)
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class moodle_database {
/** @var database_manager db manager which allows db structure modifications. */
protected $database_manager;
/** @var moodle_temptables temptables manager to provide cross-db support for temp tables. */
protected $temptables;
/** @var array Cache of table info. */
protected $tables = null;
// db connection options
/** @var string db host name. */
protected $dbhost;
/** @var string db host user. */
protected $dbuser;
/** @var string db host password. */
protected $dbpass;
/** @var string db name. */
protected $dbname;
/** @var string Prefix added to table names. */
protected $prefix;
/** @var array Database or driver specific options, such as sockets or TCP/IP db connections. */
protected $dboptions;
/** @var bool True means non-moodle external database used.*/
protected $external;
/** @var int The database reads (performance counter).*/
protected $reads = 0;
/** @var int The database writes (performance counter).*/
protected $writes = 0;
/** @var float Time queries took to finish, seconds with microseconds.*/
protected $queriestime = 0;
/** @var int Debug level. */
protected $debug = 0;
/** @var string Last used query sql. */
protected $last_sql;
/** @var array Last query parameters. */
protected $last_params;
/** @var int Last query type. */
protected $last_type;
/** @var string Last extra info. */
protected $last_extrainfo;
/** @var float Last time in seconds with millisecond precision. */
protected $last_time;
/** @var bool Flag indicating logging of query in progress. This helps prevent infinite loops. */
protected $loggingquery = false;
/** @var bool True if the db is used for db sessions. */
protected $used_for_db_sessions = false;
/** @var array Array containing open transactions. */
protected $transactions = array();
/** @var bool Flag used to force rollback of all current transactions. */
private $force_rollback = false;
/** @var string MD5 of settings used for connection. Used by MUC as an identifier. */
private $settingshash;
/** @var cache_application for column info */
protected $metacache;
/** @var cache_request for column info on temp tables */
protected $metacachetemp;
/** @var bool flag marking database instance as disposed */
protected $disposed;
/**
* @var int internal temporary variable used to fix params. Its used by {@link _fix_sql_params_dollar_callback()}.
*/
private $fix_sql_params_i;
/**
* @var int internal temporary variable used to guarantee unique parameters in each request. Its used by {@link get_in_or_equal()}.
*/
protected $inorequaluniqueindex = 1;
/**
* @var boolean variable use to temporarily disable logging.
*/
protected $skiplogging = false;
/**
* Constructor - Instantiates the database, specifying if it's external (connect to other systems) or not (Moodle DB).
* Note that this affects the decision of whether prefix checks must be performed or not.
* @param bool $external True means that an external database is used.
*/
public function __construct($external=false) {
$this->external = $external;
}
/**
* Destructor - cleans up and flushes everything needed.
*/
public function __destruct() {
$this->dispose();
}
/**
* Detects if all needed PHP stuff are installed for DB connectivity.
* Note: can be used before connect()
* @return mixed True if requirements are met, otherwise a string if something isn't installed.
*/
public abstract function driver_installed();
/**
* Returns database table prefix
* Note: can be used before connect()
* @return string The prefix used in the database.
*/
public function get_prefix() {
return $this->prefix;
}
/**
* Loads and returns a database instance with the specified type and library.
*
* The loaded class is within lib/dml directory and of the form: $type.'_'.$library.'_moodle_database'
*
* @param string $type Database driver's type. (eg: mysqli, pgsql, mssql, sqldrv, oci, etc.)
* @param string $library Database driver's library (native, pdo, etc.)
* @param bool $external True if this is an external database.
* @return moodle_database driver object or null if error, for example of driver object see {@link mysqli_native_moodle_database}
*/
public static function get_driver_instance($type, $library, $external = false) {
global $CFG;
$classname = $type.'_'.$library.'_moodle_database';
$libfile = "$CFG->libdir/dml/$classname.php";
if (!file_exists($libfile)) {
return null;
}
require_once($libfile);
return new $classname($external);
}
/**
* Returns the database vendor.
* Note: can be used before connect()
* @return string The db vendor name, usually the same as db family name.
*/
public function get_dbvendor() {
return $this->get_dbfamily();
}
/**
* Returns the database family type. (This sort of describes the SQL 'dialect')
* Note: can be used before connect()
* @return string The db family name (mysql, postgres, mssql, oracle, etc.)
*/
public abstract function get_dbfamily();
/**
* Returns a more specific database driver type
* Note: can be used before connect()
* @return string The db type mysqli, pgsql, oci, mssql, sqlsrv
*/
protected abstract function get_dbtype();
/**
* Returns the general database library name
* Note: can be used before connect()
* @return string The db library type - pdo, native etc.
*/
protected abstract function get_dblibrary();
/**
* Returns the localised database type name
* Note: can be used before connect()
* @return string
*/
public abstract function get_name();
/**
* Returns the localised database configuration help.
* Note: can be used before connect()
* @return string
*/
public abstract function get_configuration_help();
/**
* Returns the localised database description
* Note: can be used before connect()
* @deprecated since 2.6
* @return string
*/
public function get_configuration_hints() {
debugging('$DB->get_configuration_hints() method is deprecated, use $DB->get_configuration_help() instead');
return $this->get_configuration_help();
}
/**
* Returns the db related part of config.php
* @return stdClass
*/
public function export_dbconfig() {
$cfg = new stdClass();
$cfg->dbtype = $this->get_dbtype();
$cfg->dblibrary = $this->get_dblibrary();
$cfg->dbhost = $this->dbhost;
$cfg->dbname = $this->dbname;
$cfg->dbuser = $this->dbuser;
$cfg->dbpass = $this->dbpass;
$cfg->prefix = $this->prefix;
if ($this->dboptions) {
$cfg->dboptions = $this->dboptions;
}
return $cfg;
}
/**
* 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() {
return null;
}
/**
* Connects to the database.
* Must be called before other methods.
* @param string $dbhost The database host.
* @param string $dbuser The database user to connect as.
* @param string $dbpass The password to use when connecting to the database.
* @param string $dbname The name of the database being connected to.
* @param mixed $prefix string means moodle db prefix, false used for external databases where prefix not used
* @param array $dboptions driver specific options
* @return bool true
* @throws dml_connection_exception if error
*/
public abstract function connect($dbhost, $dbuser, $dbpass, $dbname, $prefix, array $dboptions=null);
/**
* Store various database settings
* @param string $dbhost The database host.
* @param string $dbuser The database user to connect as.
* @param string $dbpass The password to use when connecting to the database.
* @param string $dbname The name of the database being connected to.
* @param mixed $prefix string means moodle db prefix, false used for external databases where prefix not used
* @param array $dboptions driver specific options
* @return void
*/
protected function store_settings($dbhost, $dbuser, $dbpass, $dbname, $prefix, array $dboptions=null) {
$this->dbhost = $dbhost;
$this->dbuser = $dbuser;
$this->dbpass = $dbpass;
$this->dbname = $dbname;
$this->prefix = $prefix;
$this->dboptions = (array)$dboptions;
}
/**
* Returns a hash for the settings used during connection.
*
* If not already requested it is generated and stored in a private property.
*
* @return string
*/
protected function get_settings_hash() {
if (empty($this->settingshash)) {
$this->settingshash = md5($this->dbhost . $this->dbuser . $this->dbname . $this->prefix);
}
return $this->settingshash;
}
/**
* Handle the creation and caching of the databasemeta information for all databases.
*
* @return cache_application The databasemeta cachestore to complete operations on.
*/
protected function get_metacache() {
if (!isset($this->metacache)) {
$properties = array('dbfamily' => $this->get_dbfamily(), 'settings' => $this->get_settings_hash());
$this->metacache = cache::make('core', 'databasemeta', $properties);
}
return $this->metacache;
}
/**
* Handle the creation and caching of the temporary tables.
*
* @return cache_application The temp_tables cachestore to complete operations on.
*/
protected function get_temp_tables_cache() {
if (!isset($this->metacachetemp)) {
// Using connection data to prevent collisions when using the same temp table name with different db connections.
$properties = array('dbfamily' => $this->get_dbfamily(), 'settings' => $this->get_settings_hash());
$this->metacachetemp = cache::make('core', 'temp_tables', $properties);
}
return $this->metacachetemp;
}
/**
* Attempt to create the database
* @param string $dbhost The database host.
* @param string $dbuser The database user to connect as.
* @param string $dbpass The password to use when connecting to the database.
* @param string $dbname The name of the database being connected to.
* @param array $dboptions An array of optional database options (eg: dbport)
*
* @return bool success True for successful connection. False otherwise.
*/
public function create_database($dbhost, $dbuser, $dbpass, $dbname, array $dboptions=null) {
return false;
}
/**
* Returns transaction trace for debugging purposes.
* @private to be used by core only
* @return array or null if not in transaction.
*/
public function get_transaction_start_backtrace() {
if (!$this->transactions) {
return null;
}
$lowesttransaction = end($this->transactions);
return $lowesttransaction->get_backtrace();
}
/**
* Closes the database connection and releases all resources
* and memory (especially circular memory references).
* Do NOT use connect() again, create a new instance if needed.
* @return void
*/
public function dispose() {
if ($this->disposed) {
return;
}
$this->disposed = true;
if ($this->transactions) {
$this->force_transaction_rollback();
}
if ($this->temptables) {
$this->temptables->dispose();
$this->temptables = null;
}
if ($this->database_manager) {
$this->database_manager->dispose();
$this->database_manager = null;
}
$this->tables = null;
}
/**
* This should be called before each db query.
*
* @param string $sql The query string.
* @param array|null $params An array of parameters.
* @param int $type The type of query ( SQL_QUERY_SELECT | SQL_QUERY_AUX_READONLY | SQL_QUERY_AUX |
* SQL_QUERY_INSERT | SQL_QUERY_UPDATE | SQL_QUERY_STRUCTURE ).
* @param mixed $extrainfo This is here for any driver specific extra information.
* @return void
*/
protected function query_start($sql, ?array $params, $type, $extrainfo=null) {
if ($this->loggingquery) {
return;
}
$this->last_sql = $sql;
$this->last_params = $params;
$this->last_type = $type;
$this->last_extrainfo = $extrainfo;
$this->last_time = microtime(true);
switch ($type) {
case SQL_QUERY_SELECT:
case SQL_QUERY_AUX:
case SQL_QUERY_AUX_READONLY:
$this->reads++;
break;
case SQL_QUERY_INSERT:
case SQL_QUERY_UPDATE:
case SQL_QUERY_STRUCTURE:
$this->writes++;
default:
if ((PHPUNIT_TEST) || (defined('BEHAT_TEST') && BEHAT_TEST) ||
defined('BEHAT_SITE_RUNNING')) {
// Set list of tables that are updated.
require_once(__DIR__.'/../testing/classes/util.php');
testing_util::set_table_modified_by_sql($sql);
}
}
$this->print_debug($sql, $params);
}
/**
* This should be called immediately after each db query. It does a clean up of resources.
* It also throws exceptions if the sql that ran produced errors.
* @param mixed $result The db specific result obtained from running a query.
* @throws dml_read_exception | dml_write_exception | ddl_change_structure_exception
* @return void
*/
protected function query_end($result) {
if ($this->loggingquery) {
return;
}
if ($result !== false) {
$this->query_log();
// free memory
$this->last_sql = null;
$this->last_params = null;
$this->print_debug_time();
return;
}
// remember current info, log queries may alter it
$type = $this->last_type;
$sql = $this->last_sql;
$params = $this->last_params;
$error = $this->get_last_error();
$this->query_log($error);
switch ($type) {
case SQL_QUERY_SELECT:
case SQL_QUERY_AUX:
case SQL_QUERY_AUX_READONLY:
throw new dml_read_exception($error, $sql, $params);
case SQL_QUERY_INSERT:
case SQL_QUERY_UPDATE:
throw new dml_write_exception($error, $sql, $params);
case SQL_QUERY_STRUCTURE:
$this->get_manager(); // includes ddl exceptions classes ;-)
throw new ddl_change_structure_exception($error, $sql);
}
}
/**
* This logs the last query based on 'logall', 'logslow' and 'logerrors' options configured via $CFG->dboptions .
* @param string|bool $error or false if not error
* @return void
*/
public function query_log($error=false) {
// Logging disabled by the driver.
if ($this->skiplogging) {
return;
}
$logall = !empty($this->dboptions['logall']);
$logslow = !empty($this->dboptions['logslow']) ? $this->dboptions['logslow'] : false;
$logerrors = !empty($this->dboptions['logerrors']);
$iserror = ($error !== false);
$time = $this->query_time();
// Will be shown or not depending on MDL_PERF values rather than in dboptions['log*].
$this->queriestime = $this->queriestime + $time;
if ($logall or ($logslow and ($logslow < ($time+0.00001))) or ($iserror and $logerrors)) {
$this->loggingquery = true;
try {
$backtrace = debug_backtrace();
if ($backtrace) {
//remove query_log()
array_shift($backtrace);
}
if ($backtrace) {
//remove query_end()
array_shift($backtrace);
}
$log = new stdClass();
$log->qtype = $this->last_type;
$log->sqltext = $this->last_sql;
$log->sqlparams = var_export((array)$this->last_params, true);
$log->error = (int)$iserror;
$log->info = $iserror ? $error : null;
$log->backtrace = format_backtrace($backtrace, true);
$log->exectime = $time;
$log->timelogged = time();
$this->insert_record('log_queries', $log);
} catch (Exception $ignored) {
}
$this->loggingquery = false;
}
}
/**
* Disable logging temporarily.
*/
protected function query_log_prevent() {
$this->skiplogging = true;
}
/**
* Restore old logging behavior.
*/
protected function query_log_allow() {
$this->skiplogging = false;
}
/**
* Returns the time elapsed since the query started.
* @return float Seconds with microseconds
*/
protected function query_time() {
return microtime(true) - $this->last_time;
}
/**
* Returns database server info array
* @return array Array containing 'description' and 'version' at least.
*/
public abstract function get_server_info();
/**
* Returns supported query parameter types
* @return int bitmask of accepted SQL_PARAMS_*
*/
protected abstract function allowed_param_types();
/**
* Returns the last error reported by the database engine.
* @return string The error message.
*/
public abstract function get_last_error();
/**
* Prints sql debug info
* @param string $sql The query which is being debugged.
* @param array $params The query parameters. (optional)
* @param mixed $obj The library specific object. (optional)
* @return void
*/
protected function print_debug($sql, array $params=null, $obj=null) {
if (!$this->get_debug()) {
return;
}
if (CLI_SCRIPT) {
$separator = "--------------------------------\n";
echo $separator;
echo "{$sql}\n";
if (!is_null($params)) {
echo "[" . var_export($params, true) . "]\n";
}
echo $separator;
} else if (AJAX_SCRIPT) {
$separator = "--------------------------------";
error_log($separator);
error_log($sql);
if (!is_null($params)) {
error_log("[" . var_export($params, true) . "]");
}
error_log($separator);
} else {
$separator = "<hr />\n";
echo $separator;
echo s($sql) . "\n";
if (!is_null($params)) {
echo "[" . s(var_export($params, true)) . "]\n";
}
echo $separator;
}
}
/**
* Prints the time a query took to run.
* @return void
*/
protected function print_debug_time() {
if (!$this->get_debug()) {
return;
}
$time = $this->query_time();
$message = "Query took: {$time} seconds.\n";
if (CLI_SCRIPT) {
echo $message;
echo "--------------------------------\n";
} else if (AJAX_SCRIPT) {
error_log($message);
error_log("--------------------------------");
} else {
echo s($message);
echo "<hr />\n";
}
}
/**
* Returns the SQL WHERE conditions.
* @param string $table The table name that these conditions will be validated against.
* @param array $conditions The conditions to build the where clause. (must not contain numeric indexes)
* @throws dml_exception
* @return array An array list containing sql 'where' part and 'params'.
*/
protected function where_clause($table, array $conditions=null) {
// We accept nulls in conditions
$conditions = is_null($conditions) ? array() : $conditions;
if (empty($conditions)) {
return array('', array());
}
// Some checks performed under debugging only
if (debugging()) {
$columns = $this->get_columns($table);
if (empty($columns)) {
// no supported columns means most probably table does not exist
throw new dml_exception('ddltablenotexist', $table);
}
foreach ($conditions as $key=>$value) {
if (!isset($columns[$key])) {
$a = new stdClass();
$a->fieldname = $key;
$a->tablename = $table;
throw new dml_exception('ddlfieldnotexist', $a);
}
$column = $columns[$key];
if ($column->meta_type == 'X') {
//ok so the column is a text column. sorry no text columns in the where clause conditions
throw new dml_exception('textconditionsnotallowed', $conditions);
}
}
}
$allowed_types = $this->allowed_param_types();
$where = array();
$params = array();
foreach ($conditions as $key=>$value) {
if (is_int($key)) {
throw new dml_exception('invalidnumkey');
}
if (is_null($value)) {
$where[] = "$key IS NULL";
} else {
if ($allowed_types & SQL_PARAMS_NAMED) {
// Need to verify key names because they can contain, originally,
// spaces and other forbidden chars when using sql_xxx() functions and friends.
$normkey = trim(preg_replace('/[^a-zA-Z0-9_-]/', '_', $key), '-_');
if ($normkey !== $key) {
debugging('Invalid key found in the conditions array.');
}
$where[] = "$key = :$normkey";
$params[$normkey] = $value;
} else {
$where[] = "$key = ?";
$params[] = $value;
}
}
}
$where = implode(" AND ", $where);
return array($where, $params);
}
/**
* Returns SQL WHERE conditions for the ..._list group of methods.
*
* @param string $field the name of a field.
* @param array $values the values field might take.
* @return array An array containing sql 'where' part and 'params'
*/
protected function where_clause_list($field, array $values) {
if (empty($values)) {
return array("1 = 2", array()); // Fake condition, won't return rows ever. MDL-17645
}
// Note: Do not use get_in_or_equal() because it can not deal with bools and nulls.
$params = array();
$select = "";
$values = (array)$values;
foreach ($values as $value) {
if (is_bool($value)) {
$value = (int)$value;
}
if (is_null($value)) {
$select = "$field IS NULL";
} else {
$params[] = $value;
}
}
if ($params) {
if ($select !== "") {
$select = "$select OR ";
}
$count = count($params);
if ($count == 1) {
$select = $select."$field = ?";
} else {
$qs = str_repeat(',?', $count);
$qs = ltrim($qs, ',');
$select = $select."$field IN ($qs)";
}
}
return array($select, $params);
}
/**
* Constructs 'IN()' or '=' sql fragment
* @param mixed $items A single value or array of values for the expression.
* @param int $type Parameter bounding type : SQL_PARAMS_QM or SQL_PARAMS_NAMED.
* @param string $prefix Named parameter placeholder prefix (a unique counter value is appended to each parameter name).
* @param bool $equal True means we want to equate to the constructed expression, false means we don't want to equate to it.
* @param mixed $onemptyitems This defines the behavior when the array of items provided is empty. Defaults to false,
* meaning throw exceptions. Other values will become part of the returned SQL fragment.
* @throws coding_exception | dml_exception
* @return array A list containing the constructed sql fragment and an array of parameters.
*/
public function get_in_or_equal($items, $type=SQL_PARAMS_QM, $prefix='param', $equal=true, $onemptyitems=false) {
// default behavior, throw exception on empty array
if (is_array($items) and empty($items) and $onemptyitems === false) {
throw new coding_exception('moodle_database::get_in_or_equal() does not accept empty arrays');
}
// handle $onemptyitems on empty array of items
if (is_array($items) and empty($items)) {
if (is_null($onemptyitems)) { // Special case, NULL value
$sql = $equal ? ' IS NULL' : ' IS NOT NULL';
return (array($sql, array()));
} else {
$items = array($onemptyitems); // Rest of cases, prepare $items for std processing
}
}
if ($type == SQL_PARAMS_QM) {
if (!is_array($items) or count($items) == 1) {
$sql = $equal ? '= ?' : '<> ?';
$items = (array)$items;
$params = array_values($items);
} else {
if ($equal) {
$sql = 'IN ('.implode(',', array_fill(0, count($items), '?')).')';
} else {
$sql = 'NOT IN ('.implode(',', array_fill(0, count($items), '?')).')';
}
$params = array_values($items);
}
} else if ($type == SQL_PARAMS_NAMED) {
if (empty($prefix)) {
$prefix = 'param';
}
if (!is_array($items)){
$param = $prefix.$this->inorequaluniqueindex++;
$sql = $equal ? "= :$param" : "<> :$param";
$params = array($param=>$items);
} else if (count($items) == 1) {
$param = $prefix.$this->inorequaluniqueindex++;
$sql = $equal ? "= :$param" : "<> :$param";
$item = reset($items);
$params = array($param=>$item);
} else {
$params = array();
$sql = array();
foreach ($items as $item) {
$param = $prefix.$this->inorequaluniqueindex++;
$params[$param] = $item;
$sql[] = ':'.$param;
}
if ($equal) {
$sql = 'IN ('.implode(',', $sql).')';
} else {
$sql = 'NOT IN ('.implode(',', $sql).')';
}
}
} else {
throw new dml_exception('typenotimplement');
}
return array($sql, $params);
}
/**
* Converts short table name {tablename} to the real prefixed table name in given sql.
* @param string $sql The sql to be operated on.
* @return string The sql with tablenames being prefixed with $CFG->prefix
*/
protected function fix_table_names($sql) {
return preg_replace_callback(
'/\{([a-z][a-z0-9_]*)\}/',
function($matches) {
return $this->fix_table_name($matches[1]);
},
$sql
);
}
/**
* Adds the prefix to the table name.
*
* @param string $tablename The table name
* @return string The prefixed table name
*/
protected function fix_table_name($tablename) {
return $this->prefix . $tablename;
}
/**
* Internal private utitlity function used to fix parameters.
* Used with {@link preg_replace_callback()}
* @param array $match Refer to preg_replace_callback usage for description.
* @return string
*/
private function _fix_sql_params_dollar_callback($match) {
$this->fix_sql_params_i++;
return "\$".$this->fix_sql_params_i;
}
/**
* Detects object parameters and throws exception if found
* @param mixed $value
* @return void
* @throws coding_exception if object detected
*/
protected function detect_objects($value) {
if (is_object($value)) {
throw new coding_exception('Invalid database query parameter value', 'Objects are are not allowed: '.get_class($value));
}
}
/**
* Normalizes sql query parameters and verifies parameters.
* @param string $sql The query or part of it.
* @param array $params The query parameters.
* @return array (sql, params, type of params)
*/
public function fix_sql_params($sql, array $params=null) {
$params = (array)$params; // mke null array if needed
$allowed_types = $this->allowed_param_types();
// convert table names
$sql = $this->fix_table_names($sql);
// cast booleans to 1/0 int and detect forbidden objects
foreach ($params as $key => $value) {
$this->detect_objects($value);
$params[$key] = is_bool($value) ? (int)$value : $value;
}
// NICOLAS C: Fixed regexp for negative backwards look-ahead of double colons. Thanks for Sam Marshall's help
$named_count = preg_match_all('/(?<!:):[a-z][a-z0-9_]*/', $sql, $named_matches); // :: used in pgsql casts
$dollar_count = preg_match_all('/\$[1-9][0-9]*/', $sql, $dollar_matches);
$q_count = substr_count($sql, '?');
// Optionally add debug trace to sql as a comment.
$sql = $this->add_sql_debugging($sql);
$count = 0;
if ($named_count) {
$type = SQL_PARAMS_NAMED;
$count = $named_count;
}
if ($dollar_count) {
if ($count) {
throw new dml_exception('mixedtypesqlparam');
}
$type = SQL_PARAMS_DOLLAR;
$count = $dollar_count;
}
if ($q_count) {
if ($count) {
throw new dml_exception('mixedtypesqlparam');
}
$type = SQL_PARAMS_QM;
$count = $q_count;
}
if (!$count) {
// ignore params
if ($allowed_types & SQL_PARAMS_NAMED) {
return array($sql, array(), SQL_PARAMS_NAMED);
} else if ($allowed_types & SQL_PARAMS_QM) {
return array($sql, array(), SQL_PARAMS_QM);
} else {
return array($sql, array(), SQL_PARAMS_DOLLAR);
}
}
if ($count > count($params)) {
$a = new stdClass;
$a->expected = $count;
$a->actual = count($params);
throw new dml_exception('invalidqueryparam', $a);
}
$target_type = $allowed_types;
if ($type & $allowed_types) { // bitwise AND
if ($count == count($params)) {
if ($type == SQL_PARAMS_QM) {
return array($sql, array_values($params), SQL_PARAMS_QM); // 0-based array required
} else {
//better do the validation of names below
}
}
// needs some fixing or validation - there might be more params than needed
$target_type = $type;
}
if ($type == SQL_PARAMS_NAMED) {
$finalparams = array();
foreach ($named_matches[0] as $key) {
$key = trim($key, ':');
if (!array_key_exists($key, $params)) {
throw new dml_exception('missingkeyinsql', $key, '');
}
if (strlen($key) > 30) {
throw new coding_exception(
"Placeholder names must be 30 characters or shorter. '" .
$key . "' is too long.", $sql);
}
$finalparams[$key] = $params[$key];
}
if ($count != count($finalparams)) {
throw new dml_exception('duplicateparaminsql');
}
if ($target_type & SQL_PARAMS_QM) {
$sql = preg_replace('/(?<!:):[a-z][a-z0-9_]*/', '?', $sql);
return array($sql, array_values($finalparams), SQL_PARAMS_QM); // 0-based required
} else if ($target_type & SQL_PARAMS_NAMED) {
return array($sql, $finalparams, SQL_PARAMS_NAMED);
} else { // $type & SQL_PARAMS_DOLLAR
//lambda-style functions eat memory - we use globals instead :-(
$this->fix_sql_params_i = 0;
$sql = preg_replace_callback('/(?<!:):[a-z][a-z0-9_]*/', array($this, '_fix_sql_params_dollar_callback'), $sql);
return array($sql, array_values($finalparams), SQL_PARAMS_DOLLAR); // 0-based required
}
} else if ($type == SQL_PARAMS_DOLLAR) {
if ($target_type & SQL_PARAMS_DOLLAR) {
return array($sql, array_values($params), SQL_PARAMS_DOLLAR); // 0-based required
} else if ($target_type & SQL_PARAMS_QM) {
$sql = preg_replace('/\$[0-9]+/', '?', $sql);
return array($sql, array_values($params), SQL_PARAMS_QM); // 0-based required
} else { //$target_type & SQL_PARAMS_NAMED
$sql = preg_replace('/\$([0-9]+)/', ':param\\1', $sql);
$finalparams = array();
foreach ($params as $key=>$param) {
$key++;
$finalparams['param'.$key] = $param;
}
return array($sql, $finalparams, SQL_PARAMS_NAMED);
}
} else { // $type == SQL_PARAMS_QM
if (count($params) != $count) {
$params = array_slice($params, 0, $count);
}
if ($target_type & SQL_PARAMS_QM) {
return array($sql, array_values($params), SQL_PARAMS_QM); // 0-based required
} else if ($target_type & SQL_PARAMS_NAMED) {
$finalparams = array();
$pname = 'param0';
$parts = explode('?', $sql);
$sql = array_shift($parts);
foreach ($parts as $part) {
$param = array_shift($params);
$pname++;
$sql .= ':'.$pname.$part;
$finalparams[$pname] = $param;
}
return array($sql, $finalparams, SQL_PARAMS_NAMED);
} else { // $type & SQL_PARAMS_DOLLAR
//lambda-style functions eat memory - we use globals instead :-(
$this->fix_sql_params_i = 0;
$sql = preg_replace_callback('/\?/', array($this, '_fix_sql_params_dollar_callback'), $sql);
return array($sql, array_values($params), SQL_PARAMS_DOLLAR); // 0-based required
}
}
}
/**
* Add an SQL comment to trace all sql calls back to the calling php code
* @param string $sql Original sql
* @return string Instrumented sql
*/
protected function add_sql_debugging(string $sql): string {
global $CFG;
if (!property_exists($CFG, 'debugsqltrace')) {
return $sql;
}
$level = $CFG->debugsqltrace;
if (empty($level)) {
return $sql;
}
$callers = debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS);
// Ignore moodle_database internals.
$callers = array_filter($callers, function($caller) {
return empty($caller['class']) || $caller['class'] != 'moodle_database';
});
$callers = array_slice($callers, 0, $level);
$text = trim(format_backtrace($callers, true));
// Convert all linebreaks to SQL comments, optionally
// also eating any * formatting.
$text = preg_replace("/(^|\n)\*?\s*/", "\n-- ", $text);
// Convert all ? to 'unknown' in the sql coment so these don't get
// caught by fix_sql_params().
$text = str_replace('?', 'unknown', $text);
// Convert tokens like :test to ::test for the same reason.
$text = preg_replace('/(?<!:):[a-z][a-z0-9_]*/', ':\0', $text);
return $sql . $text;
}
/**
* Ensures that limit params are numeric and positive integers, to be passed to the database.
* We explicitly treat null, '' and -1 as 0 in order to provide compatibility with how limit
* values have been passed historically.
*
* @param int $limitfrom Where to start results from
* @param int $limitnum How many results to return
* @return array Normalised limit params in array($limitfrom, $limitnum)
*/
protected function normalise_limit_from_num($limitfrom, $limitnum) {
global $CFG;
// We explicilty treat these cases as 0.
if ($limitfrom === null || $limitfrom === '' || $limitfrom === -1) {
$limitfrom = 0;
}
if ($limitnum === null || $limitnum === '' || $limitnum === -1) {
$limitnum = 0;
}
if ($CFG->debugdeveloper) {
if (!is_numeric($limitfrom)) {
$strvalue = var_export($limitfrom, true);
debugging("Non-numeric limitfrom parameter detected: $strvalue, did you pass the correct arguments?",
DEBUG_DEVELOPER);
} else if ($limitfrom < 0) {
debugging("Negative limitfrom parameter detected: $limitfrom, did you pass the correct arguments?",
DEBUG_DEVELOPER);
}
if (!is_numeric($limitnum)) {
$strvalue = var_export($limitnum, true);
debugging("Non-numeric limitnum parameter detected: $strvalue, did you pass the correct arguments?",
DEBUG_DEVELOPER);
} else if ($limitnum < 0) {
debugging("Negative limitnum parameter detected: $limitnum, did you pass the correct arguments?",
DEBUG_DEVELOPER);
}
}
$limitfrom = (int)$limitfrom;
$limitnum = (int)$limitnum;
$limitfrom = max(0, $limitfrom);
$limitnum = max(0, $limitnum);
return array($limitfrom, $limitnum);
}
/**
* Return tables in database WITHOUT current prefix.
* @param bool $usecache if true, returns list of cached tables.
* @return array of table names in lowercase and without prefix
*/
public abstract function get_tables($usecache=true);
/**
* Return table indexes - everything lowercased.
* @param string $table The table we want to get indexes from.
* @return array An associative array of indexes containing 'unique' flag and 'columns' being indexed
*/
public abstract function get_indexes($table);
/**
* Returns detailed information about columns in table. This information is cached internally.
*
* @param string $table The table's name.
* @param bool $usecache Flag to use internal cacheing. The default is true.
* @return database_column_info[] of database_column_info objects indexed with column names
*/
public function get_columns($table, $usecache = true): array {
if (!$table) { // Table not specified, return empty array directly.
return [];
}
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 = $this->fetch_columns($table);
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;
}
/**
* Returns detailed information about columns in table. This information is cached internally.
*
* @param string $table The table's name.
* @return database_column_info[] of database_column_info objects indexed with column names
*/
protected abstract function fetch_columns(string $table): array;
/**
* Normalise values based on varying RDBMS's dependencies (booleans, LOBs...)
*
* @param database_column_info $column column metadata corresponding with the value we are going to normalise
* @param mixed $value value we are going to normalise
* @return mixed the normalised value
*/
protected abstract function normalise_value($column, $value);
/**
* Resets the internal column details cache
*
* @param array|null $tablenames an array of xmldb table names affected by this request.
* @return void
*/
public function reset_caches($tablenames = null) {
if (!empty($tablenames)) {
$dbmetapurged = false;
foreach ($tablenames as $tablename) {
if ($this->temptables->is_temptable($tablename)) {
$this->get_temp_tables_cache()->delete($tablename);
} else if ($dbmetapurged === false) {
$this->tables = null;
$this->get_metacache()->purge();
$this->metacache = null;
$dbmetapurged = true;
}
}
} else {
$this->get_temp_tables_cache()->purge();
$this->tables = null;
// Purge MUC as well.
$this->get_metacache()->purge();
$this->metacache = null;
}
}
/**
* Returns the sql generator used for db manipulation.
* Used mostly in upgrade.php scripts.
* @return database_manager The instance used to perform ddl operations.
* @see lib/ddl/database_manager.php
*/
public function get_manager() {
global $CFG;
if (!$this->database_manager) {
require_once($CFG->libdir.'/ddllib.php');
$classname = $this->get_dbfamily().'_sql_generator';
require_once("$CFG->libdir/ddl/$classname.php");
$generator = new $classname($this, $this->temptables);
$this->database_manager = new database_manager($this, $generator);
}
return $this->database_manager;
}
/**
* Attempts to change db encoding to UTF-8 encoding if possible.
* @return bool True is successful.
*/
public function change_db_encoding() {
return false;
}
/**
* Checks to see if the database is in unicode mode?
* @return bool
*/
public function setup_is_unicodedb() {
return true;
}
/**
* Enable/disable very detailed debugging.
* @param bool $state
* @return void
*/
public function set_debug($state) {
$this->debug = $state;
}
/**
* Returns debug status
* @return bool $state
*/
public function get_debug() {
return $this->debug;
}
/**
* Enable/disable detailed sql logging
*
* @deprecated since Moodle 2.9
*/
public function set_logging($state) {
throw new coding_exception('set_logging() can not be used any more.');
}
/**
* Do NOT use in code, this is for use by database_manager only!
* @param string|array $sql query or array of queries
* @param array|null $tablenames an array of xmldb table names affected by this request.
* @return bool true
* @throws ddl_change_structure_exception A DDL specific exception is thrown for any errors.
*/
public abstract function change_database_structure($sql, $tablenames = null);
/**
* Executes a 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 $params query parameters
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function execute($sql, array $params=null);
/**
* Get a number of records as a moodle_recordset where all the given conditions met.
*
* Selects records from the table $table.
*
* If specified, only records meeting $conditions.
*
* If specified, the results will be sorted as specified by $sort. This
* is added to the SQL as "ORDER BY $sort". Example values of $sort
* might be "time ASC" or "time DESC".
*
* If $fields is specified, only those fields are returned.
*
* 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 - it leads to simpler code.
*
* If you only want some of the records, specify $limitfrom and $limitnum.
* The query will skip the first $limitfrom records (according to the sort
* order) and then return the next $limitnum records. If either of $limitfrom
* or $limitnum is specified, both must be present.
*
* The return value is a moodle_recordset
* if the query succeeds. If an error occurs, false is returned.
*
* @param string $table the table to query.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default all fields are returned).
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return moodle_recordset A moodle_recordset instance
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_recordset($table, array $conditions=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) {
list($select, $params) = $this->where_clause($table, $conditions);
return $this->get_recordset_select($table, $select, $params, $sort, $fields, $limitfrom, $limitnum);
}
/**
* Get a number of records as a moodle_recordset where one field match one list of values.
*
* Only records where $field takes one of the values $values are returned.
* $values must be an array of values.
*
* Other arguments and the return type are like {@link function get_recordset}.
*
* @param string $table the table to query.
* @param string $field a field to check (optional).
* @param array $values array of values the field must have
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default all fields are returned).
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return moodle_recordset A moodle_recordset instance.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_recordset_list($table, $field, array $values, $sort='', $fields='*', $limitfrom=0, $limitnum=0) {
list($select, $params) = $this->where_clause_list($field, $values);
return $this->get_recordset_select($table, $select, $params, $sort, $fields, $limitfrom, $limitnum);
}
/**
* Get a number of records as a moodle_recordset which match a particular WHERE clause.
*
* If given, $select is used as the SELECT parameter in the SQL query,
* otherwise all records from the table are returned.
*
* Other arguments and the return type are like {@link function get_recordset}.
*
* @param string $table the table to query.
* @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
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default all fields are returned).
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return moodle_recordset A moodle_recordset instance.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_recordset_select($table, $select, array $params=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) {
$sql = "SELECT $fields FROM {".$table."}";
if ($select) {
$sql .= " WHERE $select";
}
if ($sort) {
$sql .= " ORDER BY $sort";
}
return $this->get_recordset_sql($sql, $params, $limitfrom, $limitnum);
}
/**
* 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 {@link 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).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return moodle_recordset A moodle_recordset instance.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function get_recordset_sql($sql, array $params=null, $limitfrom=0, $limitnum=0);
/**
* 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) {
return $this->get_recordset($table, array());
}
/**
* Get a number of records as an array of objects where all the given conditions met.
*
* If the query succeeds and returns at least one record, the
* return value is an array of objects, one object for each
* record found. The array key is the value from the first
* column of the result set. The object associated with that key
* has a member variable for each column of the results.
*
* @param string $table the table to query.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return (optional, by default
* all fields are returned). The first field will be used as key for the
* array so must be a unique field such as 'id'.
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records in total (optional, required if $limitfrom is set).
* @return array An array of Objects indexed by first column.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_records($table, array $conditions=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) {
list($select, $params) = $this->where_clause($table, $conditions);
return $this->get_records_select($table, $select, $params, $sort, $fields, $limitfrom, $limitnum);
}
/**
* Get a number of records as an array of objects where one field match one list of values.
*
* Return value is like {@link function get_records}.
*
* @param string $table The database table to be checked against.
* @param string $field The field to search
* @param array $values An array of values
* @param string $sort Sort order (as valid SQL sort parameter)
* @param string $fields A comma separated list of fields to be returned from the chosen table. If specified,
* the first field should be a unique one such as 'id' since it will be used as a key in the associative
* array.
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records in total (optional).
* @return array An array of objects indexed by first column
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_records_list($table, $field, array $values, $sort='', $fields='*', $limitfrom=0, $limitnum=0) {
list($select, $params) = $this->where_clause_list($field, $values);
return $this->get_records_select($table, $select, $params, $sort, $fields, $limitfrom, $limitnum);
}
/**
* Get a number of records as an array of objects which match a particular WHERE clause.
*
* Return value is like {@link function get_records}.
*
* @param string $table The table to query.
* @param string $select A fragment of SQL to be used in a where clause in the SQL call.
* @param array $params An array of sql parameters
* @param string $sort An order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields A comma separated list of fields to return
* (optional, by default all fields are returned). The first field will be used as key for the
* array so must be a unique field such as 'id'.
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records in total (optional, required if $limitfrom is set).
* @return array of objects indexed by first column
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_records_select($table, $select, array $params=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) {
if ($select) {
$select = "WHERE $select";
}
if ($sort) {
$sort = " ORDER BY $sort";
}
return $this->get_records_sql("SELECT $fields FROM {" . $table . "} $select $sort", $params, $limitfrom, $limitnum);
}
/**
* Get a number of records as an array of objects using a SQL statement.
*
* Return value is like {@link 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).
* @param int $limitnum return a subset comprising this many records in total (optional, required if $limitfrom is set).
* @return array of objects indexed by first column
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function get_records_sql($sql, array $params=null, $limitfrom=0, $limitnum=0);
/**
* Get the first two columns from a number of records as an associative array where all the given conditions met.
*
* Arguments are like {@link function get_recordset}.
*
* If no errors occur the return value
* is an associative whose keys come from the first field of each record,
* and whose values are the corresponding second fields.
* False is returned if an error occurs.
*
* @param string $table the table to query.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @param string $sort an order to sort the results in (optional, a valid SQL ORDER BY parameter).
* @param string $fields a comma separated list of fields to return - the number of fields should be 2!
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return array an associative array
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_records_menu($table, array $conditions=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) {
$menu = array();
if ($records = $this->get_records($table, $conditions, $sort, $fields, $limitfrom, $limitnum)) {
foreach ($records as $record) {
$record = (array)$record;
$key = array_shift($record);
$value = array_shift($record);
$menu[$key] = $value;
}
}
return $menu;
}
/**
* Get the first two columns from a number of records as an associative array which match a particular WHERE clause.
*
* Arguments are like {@link function get_recordset_select}.
* Return value is like {@link function get_records_menu}.
*
* @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.
* @param array $params array of sql parameters
* @param string $sort Sort order (optional) - a valid SQL order parameter
* @param string $fields A comma separated list of fields to be returned from the chosen table - the number of fields should be 2!
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return array an associative array
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_records_select_menu($table, $select, array $params=null, $sort='', $fields='*', $limitfrom=0, $limitnum=0) {
$menu = array();
if ($records = $this->get_records_select($table, $select, $params, $sort, $fields, $limitfrom, $limitnum)) {
foreach ($records as $record) {
$record = (array)$record;
$key = array_shift($record);
$value = array_shift($record);
$menu[$key] = $value;
}
}
return $menu;
}
/**
* Get the first two columns from a number of records as an associative array using a SQL statement.
*
* Arguments are like {@link function get_recordset_sql}.
* Return value is like {@link function get_records_menu}.
*
* @param string $sql The SQL string you wish to be executed.
* @param array $params array of sql parameters
* @param int $limitfrom return a subset of records, starting at this point (optional).
* @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
* @return array an associative array
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_records_sql_menu($sql, array $params=null, $limitfrom=0, $limitnum=0) {
$menu = array();
if ($records = $this->get_records_sql($sql, $params, $limitfrom, $limitnum)) {
foreach ($records as $record) {
$record = (array)$record;
$key = array_shift($record);
$value = array_shift($record);
$menu[$key] = $value;
}
}
return $menu;
}
/**
* Get a single database record as an object where all the given conditions met.
*
* @param string $table The table to select from.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @param string $fields A comma separated list of fields to be returned from the chosen table.
* @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
* IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended);
* MUST_EXIST means we will throw an exception if no record or multiple records found.
*
* @todo MDL-30407 MUST_EXIST option should not throw a dml_exception, it should throw a different exception as it's a requested check.
* @return mixed a fieldset object containing the first matching record, false or exception if error not found depending on mode
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_record($table, array $conditions, $fields='*', $strictness=IGNORE_MISSING) {
list($select, $params) = $this->where_clause($table, $conditions);
return $this->get_record_select($table, $select, $params, $fields, $strictness);
}
/**
* Get a single database record as an object 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.
* @param array $params array of sql parameters
* @param string $fields A comma separated list of fields to be returned from the chosen table.
* @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
* IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended);
* MUST_EXIST means throw exception if no record or multiple records found
* @return stdClass|false a fieldset object containing the first matching record, false or exception if error not found depending on mode
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_record_select($table, $select, array $params=null, $fields='*', $strictness=IGNORE_MISSING) {
if ($select) {
$select = "WHERE $select";
}
try {
return $this->get_record_sql("SELECT $fields FROM {" . $table . "} $select", $params, $strictness);
} catch (dml_missing_record_exception $e) {
// create new exception which will contain correct table name
throw new dml_missing_record_exception($table, $e->sql, $e->params);
}
}
/**
* Get a single database record as an object using a SQL statement.
*
* The SQL statement should normally only return one record.
* It is recommended to use get_records_sql() if more matches possible!
*
* @param string $sql The SQL string you wish to be executed, should normally only return one record.
* @param array $params array of sql parameters
* @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
* IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended);
* MUST_EXIST means throw exception if no record or multiple records found
* @return mixed a fieldset object containing the first matching record, false or exception if error not found depending on mode
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_record_sql($sql, array $params=null, $strictness=IGNORE_MISSING) {
$strictness = (int)$strictness; // we support true/false for BC reasons too
if ($strictness == IGNORE_MULTIPLE) {
$count = 1;
} else {
$count = 0;
}
if (!$records = $this->get_records_sql($sql, $params, 0, $count)) {
// not found
if ($strictness == MUST_EXIST) {
throw new dml_missing_record_exception('', $sql, $params);
}
return false;
}
if (count($records) > 1) {
if ($strictness == MUST_EXIST) {
throw new dml_multiple_records_exception($sql, $params);
}
debugging('Error: mdb->get_record() found more than one record!');
}
$return = reset($records);
return $return;
}
/**
* Get a single field value from a table record where all the given conditions met.
*
* @param string $table the table to query.
* @param string $return the field to return the value of.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
* IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended);
* MUST_EXIST means throw exception if no record or multiple records found
* @return mixed the specified value false if not found
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_field($table, $return, array $conditions, $strictness=IGNORE_MISSING) {
list($select, $params) = $this->where_clause($table, $conditions);
return $this->get_field_select($table, $return, $select, $params, $strictness);
}
/**
* Get a single field value from a table record which match a particular WHERE clause.
*
* @param string $table the table to query.
* @param string $return the field to return the value of.
* @param string $select A fragment of SQL to be used in a where clause returning one row with one column
* @param array $params array of sql parameters
* @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
* IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended);
* MUST_EXIST means throw exception if no record or multiple records found
* @return mixed the specified value false if not found
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_field_select($table, $return, $select, array $params=null, $strictness=IGNORE_MISSING) {
if ($select) {
$select = "WHERE $select";
}
try {
return $this->get_field_sql("SELECT $return FROM {" . $table . "} $select", $params, $strictness);
} catch (dml_missing_record_exception $e) {
// create new exception which will contain correct table name
throw new dml_missing_record_exception($table, $e->sql, $e->params);
}
}
/**
* Get a single field value (first field) using a SQL statement.
*
* @param string $sql The SQL query returning one row with one column
* @param array $params array of sql parameters
* @param int $strictness IGNORE_MISSING means compatible mode, false returned if record not found, debug message if more found;
* IGNORE_MULTIPLE means return first, ignore multiple records found(not recommended);
* MUST_EXIST means throw exception if no record or multiple records found
* @return mixed the specified value false if not found
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_field_sql($sql, array $params=null, $strictness=IGNORE_MISSING) {
if (!$record = $this->get_record_sql($sql, $params, $strictness)) {
return false;
}
$record = (array)$record;
return reset($record); // first column
}
/**
* Selects records and return values of chosen field as an array which match a particular WHERE clause.
*
* @param string $table the table to query.
* @param string $return the field we are intered in
* @param string $select A fragment of SQL to be used in a where clause in the SQL call.
* @param array $params array of sql parameters
* @return array of values
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_fieldset_select($table, $return, $select, array $params=null) {
if ($select) {
$select = "WHERE $select";
}
return $this->get_fieldset_sql("SELECT $return FROM {" . $table . "} $select", $params);
}
/**
* Selects records and return values (first field) as an array using a SQL statement.
*
* @param string $sql The SQL query
* @param array $params array of sql parameters
* @return array of values
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function get_fieldset_sql($sql, array $params=null);
/**
* 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 stdClass|array $params data record as object or array
* @param bool $returnid Returns id of inserted record.
* @param bool $bulk true means repeated inserts expected
* @param bool $customsequence true if 'id' included in $params, disables $returnid
* @return bool|int true or new id
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function insert_record_raw($table, $params, $returnid=true, $bulk=false, $customsequence=false);
/**
* 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|array $dataobject 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.
* @param bool $bulk Set to true is multiple inserts are expected
* @return bool|int true or new id
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function insert_record($table, $dataobject, $returnid=true, $bulk=false);
/**
* 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');
}
$fields = null;
// Note: override in driver if there is a faster way.
foreach ($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);
} else if ($fields !== array_keys($dataobject)) {
throw new coding_exception('All dataobjects in insert_records() must have the same structure!');
}
$this->insert_record($table, $dataobject, false);
}
}
/**
* 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 $dataobject A data object with values for one or more fields in the record
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function import_record($table, $dataobject);
/**
* 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 stdClass|array $params data record as object or array
* @param bool $bulk True means repeated updates expected.
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function update_record_raw($table, $params, $bulk=false);
/**
* 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 stdClass|array $dataobject An object with contents equal to fieldname=>fieldvalue.
> * Must have an entry for 'id' to map to the table specified.
* @param bool $bulk True means repeated updates expected.
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function update_record($table, $dataobject, $bulk=false);
/**
* Set a single field in every table record where all the given conditions met.
*
* @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 mixed $newvalue the value to set the field to.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function set_field($table, $newfield, $newvalue, array $conditions=null) {
list($select, $params) = $this->where_clause($table, $conditions);
return $this->set_field_select($table, $newfield, $newvalue, $select, $params);
}
/**
* 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 mixed $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 $params array of sql parameters
* @return bool true
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function set_field_select($table, $newfield, $newvalue, $select, array $params=null);
/**
* Count the records in a table where all the given conditions met.
*
* @param string $table The table to query.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @return int The count of records returned from the specified criteria.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function count_records($table, array $conditions=null) {
list($select, $params) = $this->where_clause($table, $conditions);
return $this->count_records_select($table, $select, $params);
}
/**
* Count the records in 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.
* @param array $params array of sql parameters
* @param string $countitem The count string to be used in the SQL call. Default is COUNT('x').
* @return int The count of records returned from the specified criteria.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function count_records_select($table, $select, array $params=null, $countitem="COUNT('x')") {
if ($select) {
$select = "WHERE $select";
}
return $this->count_records_sql("SELECT $countitem FROM {" . $table . "} $select", $params);
}
/**
* Get the result of a SQL SELECT COUNT(...) query.
*
* Given a query that counts rows, return that count. (In fact,
* given any query, return the first field of the first record
* returned. However, this method should only be used for the
* intended purpose.) If an error occurs, 0 is returned.
*
* @param string $sql The SQL string you wish to be executed.
* @param array $params array of sql parameters
* @return int the count
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function count_records_sql($sql, array $params=null) {
$count = $this->get_field_sql($sql, $params);
if ($count === false or !is_number($count) or $count < 0) {
throw new coding_exception("count_records_sql() expects the first field to contain non-negative number from COUNT(), '$count' found instead.");
}
return (int)$count;
}
/**
* Test whether a record exists in a table where all the given conditions met.
*
* @param string $table The table to check.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @return bool true if a matching record exists, else false.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function record_exists($table, array $conditions) {
list($select, $params) = $this->where_clause($table, $conditions);
return $this->record_exists_select($table, $select, $params);
}
/**
* Test whether any records exists in 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.
* @param array $params array of sql parameters
* @return bool true if a matching record exists, else false.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function record_exists_select($table, $select, array $params=null) {
if ($select) {
$select = "WHERE $select";
}
return $this->record_exists_sql("SELECT 'x' FROM {" . $table . "} $select", $params);
}
/**
* Test whether a SQL SELECT statement returns any records.
*
* This function returns true if the SQL statement executes
* without any errors and returns at least one record.
*
* @param string $sql The SQL statement to execute.
* @param array $params array of sql parameters
* @return bool true if the SQL executes without errors and returns at least one record.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function record_exists_sql($sql, array $params=null) {
$mrs = $this->get_recordset_sql($sql, $params, 0, 1);
$return = $mrs->valid();
$mrs->close();
return $return;
}
/**
* Delete the records from a table where all the given conditions met.
* If conditions not specified, table is truncated.
*
* @param string $table the table to delete from.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @return bool true.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function delete_records($table, array $conditions=null) {
// truncate is drop/create (DDL), not transactional safe,
// so we don't use the shortcut within them. MDL-29198
if (is_null($conditions) && empty($this->transactions)) {
return $this->execute("TRUNCATE TABLE {".$table."}");
}
list($select, $params) = $this->where_clause($table, $conditions);
return $this->delete_records_select($table, $select, $params);
}
/**
* Delete the records from a table where one field match one list of values.
*
* @param string $table the table to delete from.
* @param string $field The field to search
* @param array $values array of values
* @return bool true.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function delete_records_list($table, $field, array $values) {
list($select, $params) = $this->where_clause_list($field, $values);
return $this->delete_records_select($table, $select, $params);
}
/**
* Deletes records from a table using a subquery. The subquery should return a list of values
* in a single column, which match one field from the table being deleted.
*
* The $alias parameter must be set to the name of the single column in your subquery result
* (e.g. if the subquery is 'SELECT id FROM whatever', then it should be 'id'). This is not
* needed on most databases, but MySQL requires it.
*
* (On database where the subquery is inefficient, it is implemented differently.)
*
* @param string $table Table to delete from
* @param string $field Field in table to match
* @param string $alias Name of single column in subquery e.g. 'id'
* @param string $subquery Subquery that will return values of the field to delete
* @param array $params Parameters for subquery
* @throws dml_exception If there is any error
* @since Moodle 3.10
*/
public function delete_records_subquery(string $table, string $field, string $alias,
string $subquery, array $params = []): void {
$this->delete_records_select($table, $field . ' IN (' . $subquery . ')', $params);
}
/**
* 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 $params array of sql parameters
* @return bool true.
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public abstract function delete_records_select($table, $select, array $params=null);
/**
* Returns the FROM clause required by some DBs in all SELECT statements.
*
* To be used in queries not having FROM clause to provide cross_db
* Most DBs don't need it, hence the default is ''
* @return string
*/
public function sql_null_from_clause() {
return '';
}
/**
* Returns the SQL text to be used in order to perform one bitwise AND operation
* between 2 integers.
*
* NOTE: The SQL result is a number and can not be used directly in
* SQL condition, please compare it to some number to get a bool!!
*
< * @param int $int1 First integer in the operation.
< * @param int $int2 Second integer in the operation.
> * @param string $int1 SQL for the first integer in the operation.
> * @param string $int2 SQL for the second integer in the operation.
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_bitand($int1, $int2) {
return '((' . $int1 . ') & (' . $int2 . '))';
}
/**
* Returns the SQL text to be used in order to perform one bitwise NOT operation
* with 1 integer.
*
* @param int $int1 The operand integer in the operation.
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_bitnot($int1) {
return '(~(' . $int1 . '))';
}
/**
* Returns the SQL text to be used in order to perform one bitwise OR operation
* between 2 integers.
*
* NOTE: The SQL result is a number and can not be used directly in
* SQL condition, please compare it to some number to get a bool!!
*
* @param int $int1 The first operand integer in the operation.
* @param int $int2 The second operand integer in the operation.
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_bitor($int1, $int2) {
return '((' . $int1 . ') | (' . $int2 . '))';
}
/**
* Returns the SQL text to be used in order to perform one bitwise XOR operation
* between 2 integers.
*
* NOTE: The SQL result is a number and can not be used directly in
* SQL condition, please compare it to some number to get a bool!!
*
* @param int $int1 The first operand integer in the operation.
* @param int $int2 The second operand integer in the operation.
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_bitxor($int1, $int2) {
return '((' . $int1 . ') ^ (' . $int2 . '))';
}
/**
* Returns the SQL text to be used in order to perform module '%'
* operation - remainder after division
*
* @param int $int1 The first operand integer in the operation.
* @param int $int2 The second operand integer in the operation.
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_modulo($int1, $int2) {
return '((' . $int1 . ') % (' . $int2 . '))';
}
/**
* Returns the cross db correct CEIL (ceiling) expression applied to fieldname.
* note: Most DBs use CEIL(), hence it's the default here.
*
* @param string $fieldname The field (or expression) we are going to ceil.
* @return string The piece of SQL code to be used in your ceiling statement.
*/
public function sql_ceil($fieldname) {
return ' CEIL(' . $fieldname . ')';
}
/**
* Return SQL for casting to char of given field/expression. Default implementation performs implicit cast using
* concatenation with an empty string
*
* @param string $field Table field or SQL expression to be cast
* @return string
*/
public function sql_cast_to_char(string $field): string {
return $this->sql_concat("''", $field);
}
/**
* Returns the SQL to be used in order to CAST one CHAR column to INTEGER.
*
* Be aware that the CHAR column you're trying to cast contains really
* int values or the RDBMS will throw an error!
*
* @param string $fieldname The name of the field to be casted.
* @param bool $text Specifies if the original column is one TEXT (CLOB) column (true). Defaults to false.
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_cast_char2int($fieldname, $text=false) {
return ' ' . $fieldname . ' ';
}
/**
* Returns the SQL to be used in order to CAST one CHAR column to REAL number.
*
* Be aware that the CHAR column you're trying to cast contains really
* numbers or the RDBMS will throw an error!
*
* @param string $fieldname The name of the field to be casted.
* @param bool $text Specifies if the original column is one TEXT (CLOB) column (true). Defaults to false.
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_cast_char2real($fieldname, $text=false) {
return ' ' . $fieldname . ' ';
}
/**
* Returns the SQL to be used in order to an UNSIGNED INTEGER column to SIGNED.
*
* (Only MySQL needs this. MySQL things that 1 * -1 = 18446744073709551615
* if the 1 comes from an unsigned column).
*
* @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 ' ' . $fieldname . ' ';
}
/**
* Returns the SQL text to be used to compare one TEXT (clob) column with
* one varchar column, because some RDBMS doesn't support such direct
* comparisons.
*
* @param string $fieldname The name of the TEXT field we need to order by
* @param int $numchars Number of chars to use for the ordering (defaults to 32).
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_compare_text($fieldname, $numchars=32) {
return $this->sql_order_by_text($fieldname, $numchars);
}
/**
* Returns an equal (=) or not equal (<>) part of a query.
*
* Note the use of this method may lead to slower queries (full scans) so
* use it only when needed and against already reduced data sets.
*
* @since Moodle 3.2
*
* @param string $fieldname Usually the name of the table column.
* @param string $param Usually the bound query parameter (?, :named).
* @param bool $casesensitive Use case sensitive search when set to true (default).
* @param bool $accentsensitive Use accent sensitive search when set to true (default). (not all databases support accent insensitive)
* @param bool $notequal True means not equal (<>)
* @return string The SQL code fragment.
*/
public function sql_equal($fieldname, $param, $casesensitive = true, $accentsensitive = true, $notequal = false) {
// Note that, by default, it's assumed that the correct sql equal operations are
// case sensitive. Only databases not observing this behavior must override the method.
// Also, accent sensitiveness only will be handled by databases supporting it.
$equalop = $notequal ? '<>' : '=';
if ($casesensitive) {
return "$fieldname $equalop $param";
} else {
return "LOWER($fieldname) $equalop LOWER($param)";
}
}
/**
* Returns 'LIKE' part of a query.
*
* @param string $fieldname Usually the name of the table column.
* @param string $param Usually the bound query parameter (?, :named).
* @param bool $casesensitive Use case sensitive search when set to true (default).
* @param bool $accentsensitive Use accent sensitive search when set to true (default). (not all databases support accent insensitive)
* @param bool $notlike True means "NOT LIKE".
* @param string $escapechar The escape char for '%' and '_'.
* @return string The SQL code fragment.
*/
public function sql_like($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)');
}
$LIKE = $notlike ? 'NOT LIKE' : 'LIKE';
// by default ignore any sensitiveness - each database does it in a different way
return "$fieldname $LIKE $param ESCAPE '$escapechar'";
}
/**
* Escape sql LIKE special characters like '_' or '%'.
* @param string $text The string containing characters needing escaping.
* @param string $escapechar The desired escape character, defaults to '\\'.
* @return string The escaped sql LIKE string.
*/
public function sql_like_escape($text, $escapechar = '\\') {
$text = str_replace('_', $escapechar.'_', $text);
$text = str_replace('%', $escapechar.'%', $text);
return $text;
}
/**
* Returns the proper SQL to do CONCAT between the elements(fieldnames) passed.
*
* This function accepts variable number of string parameters.
* All strings/fieldnames will used in the SQL concatenate statement generated.
*
* @return string The SQL to concatenate strings passed in.
* @uses func_get_args() and thus parameters are unlimited OPTIONAL number of additional field names.
*/
public abstract function sql_concat();
/**
* Returns the proper SQL to do CONCAT between the elements passed
* with a given separator
*
* @param string $separator The separator desired for the SQL concatenating $elements.
* @param array $elements The array of strings to be concatenated.
* @return string The SQL to concatenate the strings.
*/
public abstract function sql_concat_join($separator="' '", $elements=array());
/**
* Return SQL for performing group concatenation on given field/expression
*
* @param string $field Table field or SQL expression to be concatenated
* @param string $separator The separator desired between each concatetated field
* @param string $sort Ordering of the concatenated field
* @return string
*/
public abstract function sql_group_concat(string $field, string $separator = ', ', string $sort = ''): string;
/**
* Returns the proper SQL (for the dbms in use) to concatenate $firstname and $lastname
*
* @todo MDL-31233 This may not be needed here.
*
* @param string $first User's first name (default:'firstname').
* @param string $last User's last name (default:'lastname').
* @return string The SQL to concatenate strings.
*/
function sql_fullname($first='firstname', $last='lastname') {
return $this->sql_concat($first, "' '", $last);
}
/**
* Returns the SQL text to be used to order by one TEXT (clob) column, because
* some RDBMS doesn't support direct ordering of such fields.
*
* Note that the use or queries being ordered by TEXT columns must be minimised,
* because it's really slooooooow.
*
* @param string $fieldname The name of the TEXT field we need to order by.
* @param int $numchars The number of chars to use for the ordering (defaults to 32).
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_order_by_text($fieldname, $numchars=32) {
return $fieldname;
}
/**
* Returns the SQL text to be used to order by columns, standardising the return
* pattern of null values across database types to sort nulls first when ascending
* and last when descending.
*
* @param string $fieldname The name of the field we need to sort by.
* @param int $sort An order to sort the results in.
* @return string The piece of SQL code to be used in your statement.
*/
public function sql_order_by_null(string $fieldname, int $sort = SORT_ASC): string {
return $fieldname . ' ' . ($sort == SORT_ASC ? 'ASC' : 'DESC');
}
/**
* Returns the SQL text to be used to calculate the length in characters of one expression.
* @param string $fieldname The fieldname/expression to calculate its length in characters.
* @return string the piece of SQL code to be used in the statement.
*/
public function sql_length($fieldname) {
return ' LENGTH(' . $fieldname . ')';
}
/**
* Returns the proper substr() SQL text used to extract substrings from DB
* NOTE: this was originally returning only function name
*
* @param string $expr Some string field, no aggregates.
* @param mixed $start Integer or expression evaluating to integer (1 based value; first char has index 1)
* @param mixed $length Optional integer or expression evaluating to integer.
* @return string The sql substring extraction fragment.
*/
public function sql_substr($expr, $start, $length=false) {
if (count(func_get_args()) < 2) {
throw new coding_exception('moodle_database::sql_substr() requires at least two parameters', 'Originally this function was only returning name of SQL substring function, it now requires all parameters.');
}
if ($length === false) {
return "SUBSTR($expr, $start)";
} else {
return "SUBSTR($expr, $start, $length)";
}
}
/**
* Returns the SQL for returning searching one string for the location of another.
*
* Note, there is no guarantee which order $needle, $haystack will be in
* the resulting SQL so when using this method, and both arguments contain
* placeholders, you should use named placeholders.
*
* @param string $needle the SQL expression that will be searched for.
* @param string $haystack the SQL expression that will be searched in.
* @return string The required searching SQL part.
*/
public function sql_position($needle, $haystack) {
// Implementation using standard SQL.
return "POSITION(($needle) IN ($haystack))";
}
/**
* This used to return empty string replacement character.
*
* @deprecated use bound parameter with empty string instead
*
* @return string An empty string.
*/
function sql_empty() {
debugging("sql_empty() is deprecated, please use empty string '' as sql parameter value instead", DEBUG_DEVELOPER);
return '';
}
/**
* Returns the proper SQL to know if one field is empty.
*
* Note that the function behavior strongly relies on the
* parameters passed describing the field so, please, be accurate
* when specifying them.
*
* Also, note that this function is not suitable to look for
* fields having NULL contents at all. It's all for empty values!
*
* This function should be applied in all the places where conditions of
* the type:
*
* ... AND fieldname = '';
*
* are being used. Final result for text fields should be:
*
* ... AND ' . sql_isempty('tablename', 'fieldname', true/false, true);
*
* and for varchar fields result should be:
*
* ... AND fieldname = :empty; "; $params['empty'] = '';
*
* (see parameters description below)
*
* @param string $tablename Name of the table (without prefix). Not used for now but can be
* necessary in the future if we want to use some introspection using
* meta information against the DB. /// TODO ///
* @param string $fieldname Name of the field we are going to check
* @param bool $nullablefield For specifying if the field is nullable (true) or no (false) in the DB.
* @param bool $textfield For specifying if it is a text (also called clob) field (true) or a varchar one (false)
* @return string the sql code to be added to check for empty values
*/
public function sql_isempty($tablename, $fieldname, $nullablefield, $textfield) {
return " ($fieldname = '') ";
}
/**
* Returns the proper SQL to know if one field is not empty.
*
* Note that the function behavior strongly relies on the
* parameters passed describing the field so, please, be accurate
* when specifying them.
*
* This function should be applied in all the places where conditions of
* the type:
*
* ... AND fieldname != '';
*
* are being used. Final result for text fields should be:
*
* ... AND ' . sql_isnotempty('tablename', 'fieldname', true/false, true/false);
*
* and for varchar fields result should be:
*
* ... AND fieldname != :empty; "; $params['empty'] = '';
*
* (see parameters description below)
*
* @param string $tablename Name of the table (without prefix). This is not used for now but can be
* necessary in the future if we want to use some introspection using
* meta information against the DB.
* @param string $fieldname The name of the field we are going to check.
* @param bool $nullablefield Specifies if the field is nullable (true) or not (false) in the DB.
* @param bool $textfield Specifies if it is a text (also called clob) field (true) or a varchar one (false).
* @return string The sql code to be added to check for non empty values.
*/
public function sql_isnotempty($tablename, $fieldname, $nullablefield, $textfield) {
return ' ( NOT ' . $this->sql_isempty($tablename, $fieldname, $nullablefield, $textfield) . ') ';
}
/**
* Returns true if this database driver supports regex syntax when searching.
* @return bool True if supported.
*/
public function sql_regex_supported() {
return false;
}
/**
* Returns the driver specific syntax (SQL part) for matching regex positively or negatively (inverted matching).
* Eg: 'REGEXP':'NOT REGEXP' or '~*' : '!~*'
*
* @param bool $positivematch
* @param bool $casesensitive
* @return string or empty if not supported
*/
public function sql_regex($positivematch = true, $casesensitive = false) {
return '';
}
/**
* Returns the word-beginning boundary marker if this database driver supports regex syntax when searching.
* @return string The word-beginning boundary marker. Otherwise, an empty string.
*/
public function sql_regex_get_word_beginning_boundary_marker() {
if ($this->sql_regex_supported()) {
return '[[:<:]]';
}
return '';
}
/**
* Returns the word-end boundary marker if this database driver supports regex syntax when searching.
* @return string The word-end boundary marker. Otherwise, an empty string.
*/
public function sql_regex_get_word_end_boundary_marker() {
if ($this->sql_regex_supported()) {
return '[[:>:]]';
}
return '';
}
/**
* 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 $fields comma-separated list of fields (used only by some DB engines)
* @return string SQL query that will return only values that are present in each of selects
*/
public function sql_intersect($selects, $fields) {
if (!count($selects)) {
throw new coding_exception('sql_intersect() requires at least one element in $selects');
} else if (count($selects) == 1) {
return $selects[0];
}
static $aliascnt = 0;
$rv = '('.$selects[0].')';
for ($i = 1; $i < count($selects); $i++) {
$rv .= " INTERSECT (".$selects[$i].')';
}
return $rv;
}
/**
* Does this driver support tool_replace?
*
* @since Moodle 2.6.1
* @return bool
*/
public function replace_all_text_supported() {
return false;
}
/**
* Replace given text in all rows of column.
*
* @since Moodle 2.6.1
* @param string $table name of the table
* @param database_column_info $column
* @param string $search
* @param string $replace
*/
public function replace_all_text($table, database_column_info $column, $search, $replace) {
if (!$this->replace_all_text_supported()) {
return;
}
// NOTE: override this methods if following standard compliant SQL
// does not work for your driver.
// Enclose the column name by the proper quotes if it's a reserved word.
$columnname = $this->get_manager()->generator->getEncQuoted($column->name);
$searchsql = $this->sql_like($columnname, '?');
$searchparam = '%'.$this->sql_like_escape($search).'%';
$sql = "UPDATE {".$table."}
SET $columnname = REPLACE($columnname, ?, ?)
WHERE $searchsql";
if ($column->meta_type === 'X') {
$this->execute($sql, array($search, $replace, $searchparam));
} else if ($column->meta_type === 'C') {
if (core_text::strlen($search) < core_text::strlen($replace)) {
$colsize = $column->max_length;
$sql = "UPDATE {".$table."}
SET $columnname = " . $this->sql_substr("REPLACE(" . $columnname . ", ?, ?)", 1, $colsize) . "
WHERE $searchsql";
}
$this->execute($sql, array($search, $replace, $searchparam));
}
}
/**
* Analyze the data in temporary tables to force statistics collection after bulk data loads.
*
* @return void
*/
public function update_temp_table_stats() {
$this->temptables->update_stats();
}
/**
* Checks and returns true if transactions are supported.
*
* It is not responsible to run productions servers
* on databases without transaction support ;-)
*
* Override in driver if needed.
*
* @return bool
*/
protected function transactions_supported() {
// protected for now, this might be changed to public if really necessary
return true;
}
/**
* Returns true if a transaction is in progress.
* @return bool
*/
public function is_transaction_started() {
return !empty($this->transactions);
}
/**
* This is a test that throws an exception if transaction in progress.
* This test does not force rollback of active transactions.
* @return void
* @throws dml_transaction_exception if stansaction active
*/
public function transactions_forbidden() {
if ($this->is_transaction_started()) {
throw new dml_transaction_exception('This code can not be excecuted in transaction');
}
}
/**
* On DBs that support it, switch to transaction mode and begin a transaction
* you'll need to ensure you call allow_commit() on the returned object
* or your changes *will* be lost.
*
* this is _very_ useful for massive updates
*
* Delegated database transactions can be nested, but only one actual database
* transaction is used for the outer-most delegated transaction. This method
* returns a transaction object which you should keep until the end of the
* delegated transaction. The actual database transaction will
* only be committed if all the nested delegated transactions commit
* successfully. If any part of the transaction rolls back then the whole
* thing is rolled back.
*
* @return moodle_transaction
*/
public function start_delegated_transaction() {
$transaction = new moodle_transaction($this);
$this->transactions[] = $transaction;
if (count($this->transactions) == 1) {
$this->begin_transaction();
}
return $transaction;
}
/**
* Driver specific start of real database transaction,
* this can not be used directly in code.
* @return void
*/
protected abstract function begin_transaction();
/**
* Indicates delegated transaction finished successfully.
* The real database transaction is committed only if
* all delegated transactions committed.
* @param moodle_transaction $transaction The transaction to commit
* @return void
* @throws dml_transaction_exception Creates and throws transaction related exceptions.
*/
public function commit_delegated_transaction(moodle_transaction $transaction) {
if ($transaction->is_disposed()) {
throw new dml_transaction_exception('Transactions already disposed', $transaction);
}
// mark as disposed so that it can not be used again
$transaction->dispose();
if (empty($this->transactions)) {
throw new dml_transaction_exception('Transaction not started', $transaction);
}
if ($this->force_rollback) {
throw new dml_transaction_exception('Tried to commit transaction after lower level rollback', $transaction);
}
if ($transaction !== $this->transactions[count($this->transactions) - 1]) {
// one incorrect commit at any level rollbacks everything
$this->force_rollback = true;
throw new dml_transaction_exception('Invalid transaction commit attempt', $transaction);
}
if (count($this->transactions) == 1) {
// only commit the top most level
$this->commit_transaction();
}
array_pop($this->transactions);
if (empty($this->transactions)) {
\core\event\manager::database_transaction_commited();
\core\message\manager::database_transaction_commited();
}
}
/**
* Driver specific commit of real database transaction,
* this can not be used directly in code.
* @return void
*/
protected abstract function commit_transaction();
/**
* Call when delegated transaction failed, this rolls back
* all delegated transactions up to the top most level.
*
* In many cases you do not need to call this method manually,
* because all open delegated transactions are rolled back
* automatically if exceptions not caught.
*
* @param moodle_transaction $transaction An instance of a moodle_transaction.
* @param Exception|Throwable $e The related exception/throwable to this transaction rollback.
* @return void This does not return, instead the exception passed in will be rethrown.
*/
public function rollback_delegated_transaction(moodle_transaction $transaction, $e) {
if (!($e instanceof Exception) && !($e instanceof Throwable)) {
// PHP7 - we catch Throwables in phpunit but can't use that as the type hint in PHP5.
$e = new \coding_exception("Must be given an Exception or Throwable object!");
}
if ($transaction->is_disposed()) {
throw new dml_transaction_exception('Transactions already disposed', $transaction);
}
// mark as disposed so that it can not be used again
$transaction->dispose();
// one rollback at any level rollbacks everything
$this->force_rollback = true;
if (empty($this->transactions) or $transaction !== $this->transactions[count($this->transactions) - 1]) {
// this may or may not be a coding problem, better just rethrow the exception,
// because we do not want to loose the original $e
throw $e;
}
if (count($this->transactions) == 1) {
// only rollback the top most level
$this->rollback_transaction();
}
array_pop($this->transactions);
if (empty($this->transactions)) {
// finally top most level rolled back
$this->force_rollback = false;
\core\event\manager::database_transaction_rolledback();
\core\message\manager::database_transaction_rolledback();
}
throw $e;
}
/**
* Driver specific abort of real database transaction,
* this can not be used directly in code.
* @return void
*/
protected abstract function rollback_transaction();
/**
* Force rollback of all delegated transaction.
* Does not throw any exceptions and does not log anything.
*
* This method should be used only from default exception handlers and other
* core code.
*
* @return void
*/
public function force_transaction_rollback() {
if ($this->transactions) {
try {
$this->rollback_transaction();
} catch (dml_exception $e) {
// ignore any sql errors here, the connection might be broken
}
}
// now enable transactions again
$this->transactions = array();
$this->force_rollback = false;
\core\event\manager::database_transaction_rolledback();
\core\message\manager::database_transaction_rolledback();
}
/**
* Is session lock supported in this driver?
* @return bool
*/
public function session_lock_supported() {
return false;
}
/**
* Obtains the session lock.
* @param int $rowid The id of the row with session record.
* @param int $timeout The maximum allowed time to wait for the lock in seconds.
* @return void
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function get_session_lock($rowid, $timeout) {
$this->used_for_db_sessions = true;
}
/**
* Releases the session lock.
* @param int $rowid The id of the row with session record.
* @return void
* @throws dml_exception A DML specific exception is thrown for any errors.
*/
public function release_session_lock($rowid) {
}
/**
* Returns the number of reads done by this database.
* @return int Number of reads.
*/
public function perf_get_reads() {
return $this->reads;
}
/**
* Returns whether we want to connect to slave database for read queries.
* @return bool Want read only connection
*/
public function want_read_slave(): bool {
return false;
}
/**
* Returns the number of reads before first write done by this database.
* @return int Number of reads.
*/
public function perf_get_reads_slave(): int {
return 0;
}
/**
* Returns the number of writes done by this database.
* @return int Number of writes.
*/
public function perf_get_writes() {
return $this->writes;
}
/**
* Returns the number of queries done by this database.
* @return int Number of queries.
*/
public function perf_get_queries() {
return $this->writes + $this->reads;
}
/**
* Time waiting for the database engine to finish running all queries.
* @return float Number of seconds with microseconds
*/
public function perf_get_queries_time() {
return $this->queriestime;
}
/**
* Whether the database is able to support full-text search or not.
*
* @return bool
*/
public function is_fulltext_search_supported() {
// No support unless specified.
return false;
}
}
