/lib/dml/mssql_native_moodle_database.php
PHP | 1468 lines | 971 code | 175 blank | 322 comment | 145 complexity | f7d0571ae4b504a619f4624a3ece0ba7 MD5 | raw file
Possible License(s): Apache-2.0, LGPL-2.1, BSD-3-Clause, MIT, GPL-3.0
- <?php
- // This file is part of Moodle - http://moodle.org/
- //
- // Moodle is free software: you can redistribute it and/or modify
- // it under the terms of the GNU General Public License as published by
- // the Free Software Foundation, either version 3 of the License, or
- // (at your option) any later version.
- //
- // Moodle is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU General Public License for more details.
- //
- // You should have received a copy of the GNU General Public License
- // along with Moodle. If not, see <http://www.gnu.org/licenses/>.
- /**
- * Native mssql class representing moodle database interface.
- *
- * @package core_dml
- * @copyright 2009 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
- * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
- defined('MOODLE_INTERNAL') || die();
- require_once(__DIR__.'/moodle_database.php');
- require_once(__DIR__.'/mssql_native_moodle_recordset.php');
- require_once(__DIR__.'/mssql_native_moodle_temptables.php');
- /**
- * Native mssql class representing moodle database interface.
- *
- * @package core_dml
- * @copyright 2009 onwards Eloy Lafuente (stronk7) {@link http://stronk7.com}
- * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
- class mssql_native_moodle_database extends moodle_database {
- protected $mssql = null;
- protected $last_error_reporting; // To handle mssql driver default verbosity
- protected $collation; // current DB collation cache
- /**
- * Does the used db version support ANSI way of limiting (2012 and higher)
- * @var bool
- */
- protected $supportsoffsetfetch;
- /**
- * Detects if all needed PHP stuff installed.
- * Note: can be used before connect()
- * @return mixed true if ok, string if something
- */
- public function driver_installed() {
- if (!function_exists('mssql_connect')) {
- return get_string('mssqlextensionisnotpresentinphp', 'install');
- }
- return true;
- }
- /**
- * Returns database family type - describes SQL dialect
- * Note: can be used before connect()
- * @return string db family name (mysql, postgres, mssql, oracle, etc.)
- */
- public function get_dbfamily() {
- return 'mssql';
- }
- /**
- * Returns more specific database driver type
- * Note: can be used before connect()
- * @return string db type mysqli, pgsql, oci, mssql, sqlsrv
- */
- protected function get_dbtype() {
- return 'mssql';
- }
- /**
- * Returns general database library name
- * Note: can be used before connect()
- * @return string db type pdo, native
- */
- protected function get_dblibrary() {
- return 'native';
- }
- /**
- * Returns localised database type name
- * Note: can be used before connect()
- * @return string
- */
- public function get_name() {
- return get_string('nativemssql', 'install');
- }
- /**
- * Returns localised database configuration help.
- * Note: can be used before connect()
- * @return string
- */
- public function get_configuration_help() {
- return get_string('nativemssqlhelp', 'install');
- }
- /**
- * Diagnose database and tables, this function is used
- * to verify database and driver settings, db engine types, etc.
- *
- * @return string null means everything ok, string means problem found.
- */
- public function diagnose() {
- // Verify the database is running with READ_COMMITTED_SNAPSHOT enabled.
- // (that's required to get snapshots/row versioning on READ_COMMITED mode).
- $correctrcsmode = false;
- $sql = "SELECT is_read_committed_snapshot_on
- FROM sys.databases
- WHERE name = '{$this->dbname}'";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- if ($result) {
- if ($row = mssql_fetch_assoc($result)) {
- $correctrcsmode = (bool)reset($row);
- }
- }
- $this->free_result($result);
- if (!$correctrcsmode) {
- return get_string('mssqlrcsmodemissing', 'error');
- }
- // Arrived here, all right.
- return null;
- }
- /**
- * Connect to db
- * Must be called before other methods.
- * @param string $dbhost The database host.
- * @param string $dbuser The database username.
- * @param string $dbpass The database username's password.
- * @param string $dbname The name of the database being connected to.
- * @param mixed $prefix string means moodle db prefix, false used for external databases where prefix not used
- * @param array $dboptions driver specific options
- * @return bool true
- * @throws dml_connection_exception if error
- */
- public function connect($dbhost, $dbuser, $dbpass, $dbname, $prefix, array $dboptions=null) {
- if ($prefix == '' and !$this->external) {
- //Enforce prefixes for everybody but mysql
- throw new dml_exception('prefixcannotbeempty', $this->get_dbfamily());
- }
- $driverstatus = $this->driver_installed();
- if ($driverstatus !== true) {
- throw new dml_exception('dbdriverproblem', $driverstatus);
- }
- $this->store_settings($dbhost, $dbuser, $dbpass, $dbname, $prefix, $dboptions);
- $dbhost = $this->dbhost;
- // Zero shouldn't be used as a port number so doing a check with empty() should be fine.
- if (!empty($dboptions['dbport'])) {
- if (stristr(PHP_OS, 'win') && !stristr(PHP_OS, 'darwin')) {
- $dbhost .= ','.$dboptions['dbport'];
- } else {
- $dbhost .= ':'.$dboptions['dbport'];
- }
- }
- ob_start();
- if (!empty($this->dboptions['dbpersist'])) { // persistent connection
- $this->mssql = mssql_pconnect($dbhost, $this->dbuser, $this->dbpass, true);
- } else {
- $this->mssql = mssql_connect($dbhost, $this->dbuser, $this->dbpass, true);
- }
- $dberr = ob_get_contents();
- ob_end_clean();
- if ($this->mssql === false) {
- $this->mssql = null;
- throw new dml_connection_exception($dberr);
- }
- // Disable logging until we are fully setup.
- $this->query_log_prevent();
- // already connected, select database and set some env. variables
- $this->query_start("--mssql_select_db", null, SQL_QUERY_AUX);
- $result = mssql_select_db($this->dbname, $this->mssql);
- $this->query_end($result);
- // No need to set charset. It's UTF8, with transparent conversions
- // back and forth performed both by FreeTDS or ODBTP
- // Allow quoted identifiers
- $sql = "SET QUOTED_IDENTIFIER ON";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- // Force ANSI nulls so the NULL check was done by IS NULL and NOT IS NULL
- // instead of equal(=) and distinct(<>) symbols
- $sql = "SET ANSI_NULLS ON";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- // Force ANSI warnings so arithmetic/string overflows will be
- // returning error instead of transparently truncating data
- $sql = "SET ANSI_WARNINGS ON";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- // Concatenating null with anything MUST return NULL
- $sql = "SET CONCAT_NULL_YIELDS_NULL ON";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- // Set transactions isolation level to READ_COMMITTED
- // prevents dirty reads when using transactions +
- // is the default isolation level of MSSQL
- // Requires database to run with READ_COMMITTED_SNAPSHOT ON
- $sql = "SET TRANSACTION ISOLATION LEVEL READ COMMITTED";
- $this->query_start($sql, NULL, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- $serverinfo = $this->get_server_info();
- // Fetch/offset is supported staring from SQL Server 2012.
- $this->supportsoffsetfetch = $serverinfo['version'] > '11';
- // We can enable logging now.
- $this->query_log_allow();
- // Connection stabilised and configured, going to instantiate the temptables controller
- $this->temptables = new mssql_native_moodle_temptables($this);
- return true;
- }
- /**
- * Close database connection and release all resources
- * and memory (especially circular memory references).
- * Do NOT use connect() again, create a new instance if needed.
- */
- public function dispose() {
- parent::dispose(); // Call parent dispose to write/close session and other common stuff before closing connection
- if ($this->mssql) {
- mssql_close($this->mssql);
- $this->mssql = null;
- }
- }
- /**
- * Called before each db query.
- * @param string $sql
- * @param array array of parameters
- * @param int $type type of query
- * @param mixed $extrainfo driver specific extra information
- * @return void
- */
- protected function query_start($sql, array $params=null, $type, $extrainfo=null) {
- parent::query_start($sql, $params, $type, $extrainfo);
- // mssql driver tends to send debug to output, we do not need that ;-)
- $this->last_error_reporting = error_reporting(0);
- }
- /**
- * Called immediately after each db query.
- * @param mixed db specific result
- * @return void
- */
- protected function query_end($result) {
- // reset original debug level
- error_reporting($this->last_error_reporting);
- parent::query_end($result);
- }
- /**
- * Returns database server info array
- * @return array Array containing 'description' and 'version' info
- */
- public function get_server_info() {
- static $info;
- if (!$info) {
- $info = array();
- $sql = 'sp_server_info 2';
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $row = mssql_fetch_row($result);
- $info['description'] = $row[2];
- $this->free_result($result);
- $sql = 'sp_server_info 500';
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $row = mssql_fetch_row($result);
- $info['version'] = $row[2];
- $this->free_result($result);
- }
- return $info;
- }
- /**
- * Converts short table name {tablename} to real table name
- * supporting temp tables (#) if detected
- *
- * @param string sql
- * @return string sql
- */
- protected function fix_table_names($sql) {
- if (preg_match_all('/\{([a-z][a-z0-9_]*)\}/', $sql, $matches)) {
- foreach($matches[0] as $key=>$match) {
- $name = $matches[1][$key];
- if ($this->temptables->is_temptable($name)) {
- $sql = str_replace($match, $this->temptables->get_correct_name($name), $sql);
- } else {
- $sql = str_replace($match, $this->prefix.$name, $sql);
- }
- }
- }
- return $sql;
- }
- /**
- * Returns supported query parameter types
- * @return int bitmask of accepted SQL_PARAMS_*
- */
- protected function allowed_param_types() {
- return SQL_PARAMS_QM; // Not really, but emulated, see emulate_bound_params()
- }
- /**
- * Returns last error reported by database engine.
- * @return string error message
- */
- public function get_last_error() {
- return mssql_get_last_message();
- }
- /**
- * Return tables in database WITHOUT current prefix
- * @param bool $usecache if true, returns list of cached tables.
- * @return array of table names in lowercase and without prefix
- */
- public function get_tables($usecache=true) {
- if ($usecache and $this->tables !== null) {
- return $this->tables;
- }
- $this->tables = array();
- $sql = "SELECT table_name
- FROM INFORMATION_SCHEMA.TABLES
- WHERE table_name LIKE '$this->prefix%'
- AND table_type = 'BASE TABLE'";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- if ($result) {
- while ($row = mssql_fetch_row($result)) {
- $tablename = reset($row);
- if ($this->prefix !== false && $this->prefix !== '') {
- if (strpos($tablename, $this->prefix) !== 0) {
- continue;
- }
- $tablename = substr($tablename, strlen($this->prefix));
- }
- $this->tables[$tablename] = $tablename;
- }
- $this->free_result($result);
- }
- // Add the currently available temptables
- $this->tables = array_merge($this->tables, $this->temptables->get_temptables());
- return $this->tables;
- }
- /**
- * Return table indexes - everything lowercased.
- * @param string $table The table we want to get indexes from.
- * @return array An associative array of indexes containing 'unique' flag and 'columns' being indexed
- */
- public function get_indexes($table) {
- $indexes = array();
- $tablename = $this->prefix.$table;
- // Indexes aren't covered by information_schema metatables, so we need to
- // go to sys ones. Skipping primary key indexes on purpose.
- $sql = "SELECT i.name AS index_name, i.is_unique, ic.index_column_id, c.name AS column_name
- FROM sys.indexes i
- JOIN sys.index_columns ic ON i.object_id = ic.object_id AND i.index_id = ic.index_id
- JOIN sys.columns c ON ic.object_id = c.object_id AND ic.column_id = c.column_id
- JOIN sys.tables t ON i.object_id = t.object_id
- WHERE t.name = '$tablename'
- AND i.is_primary_key = 0
- ORDER BY i.name, i.index_id, ic.index_column_id";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- if ($result) {
- $lastindex = '';
- $unique = false;
- $columns = array();
- while ($row = mssql_fetch_assoc($result)) {
- if ($lastindex and $lastindex != $row['index_name']) { // Save lastindex to $indexes and reset info
- $indexes[$lastindex] = array('unique' => $unique, 'columns' => $columns);
- $unique = false;
- $columns = array();
- }
- $lastindex = $row['index_name'];
- $unique = empty($row['is_unique']) ? false : true;
- $columns[] = $row['column_name'];
- }
- if ($lastindex ) { // Add the last one if exists
- $indexes[$lastindex] = array('unique' => $unique, 'columns' => $columns);
- }
- $this->free_result($result);
- }
- return $indexes;
- }
- /**
- * Returns datailed information about columns in table. This information is cached internally.
- * @param string $table name
- * @param bool $usecache
- * @return array array of database_column_info objects indexed with column names
- */
- public function get_columns($table, $usecache=true) {
- if ($usecache) {
- if ($this->temptables->is_temptable($table)) {
- if ($data = $this->get_temp_tables_cache()->get($table)) {
- return $data;
- }
- } else {
- if ($data = $this->get_metacache()->get($table)) {
- return $data;
- }
- }
- }
- $structure = array();
- if (!$this->temptables->is_temptable($table)) { // normal table, get metadata from own schema
- $sql = "SELECT column_name AS name,
- data_type AS type,
- numeric_precision AS max_length,
- character_maximum_length AS char_max_length,
- numeric_scale AS scale,
- is_nullable AS is_nullable,
- columnproperty(object_id(quotename(table_schema) + '.' +
- quotename(table_name)), column_name, 'IsIdentity') AS auto_increment,
- column_default AS default_value
- FROM INFORMATION_SCHEMA.COLUMNS
- WHERE table_name = '{" . $table . "}'
- ORDER BY ordinal_position";
- } else { // temp table, get metadata from tempdb schema
- $sql = "SELECT column_name AS name,
- data_type AS type,
- numeric_precision AS max_length,
- character_maximum_length AS char_max_length,
- numeric_scale AS scale,
- is_nullable AS is_nullable,
- columnproperty(object_id(quotename(table_schema) + '.' +
- quotename(table_name)), column_name, 'IsIdentity') AS auto_increment,
- column_default AS default_value
- FROM tempdb.INFORMATION_SCHEMA.COLUMNS
- JOIN tempdb..sysobjects ON name = table_name
- WHERE id = object_id('tempdb..{" . $table . "}')
- ORDER BY ordinal_position";
- }
- list($sql, $params, $type) = $this->fix_sql_params($sql, null);
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- if (!$result) {
- return array();
- }
- while ($rawcolumn = mssql_fetch_assoc($result)) {
- $rawcolumn = (object)$rawcolumn;
- $info = new stdClass();
- $info->name = $rawcolumn->name;
- $info->type = $rawcolumn->type;
- $info->meta_type = $this->mssqltype2moodletype($info->type);
- // Prepare auto_increment info
- $info->auto_increment = $rawcolumn->auto_increment ? true : false;
- // Define type for auto_increment columns
- $info->meta_type = ($info->auto_increment && $info->meta_type == 'I') ? 'R' : $info->meta_type;
- // id columns being auto_incremnt are PK by definition
- $info->primary_key = ($info->name == 'id' && $info->meta_type == 'R' && $info->auto_increment);
- if ($info->meta_type === 'C' and $rawcolumn->char_max_length == -1) {
- // This is NVARCHAR(MAX), not a normal NVARCHAR.
- $info->max_length = -1;
- $info->meta_type = 'X';
- } else {
- // Put correct length for character and LOB types
- $info->max_length = $info->meta_type == 'C' ? $rawcolumn->char_max_length : $rawcolumn->max_length;
- $info->max_length = ($info->meta_type == 'X' || $info->meta_type == 'B') ? -1 : $info->max_length;
- }
- // Scale
- $info->scale = $rawcolumn->scale;
- // Prepare not_null info
- $info->not_null = $rawcolumn->is_nullable == 'NO' ? true : false;
- // Process defaults
- $info->has_default = !empty($rawcolumn->default_value);
- if ($rawcolumn->default_value === NULL) {
- $info->default_value = NULL;
- } else {
- $info->default_value = preg_replace("/^[\(N]+[']?(.*?)[']?[\)]+$/", '\\1', $rawcolumn->default_value);
- }
- // Process binary
- $info->binary = $info->meta_type == 'B' ? true : false;
- $structure[$info->name] = new database_column_info($info);
- }
- $this->free_result($result);
- 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;
- }
- /**
- * 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 $value value we are going to normalise
- * @return mixed the normalised value
- */
- protected function normalise_value($column, $value) {
- $this->detect_objects($value);
- if (is_bool($value)) { // Always, convert boolean to int
- $value = (int)$value;
- } // And continue processing because text columns with numeric info need special handling below
- if ($column->meta_type == 'B') { // BLOBs need to be properly "packed", but can be inserted directly if so.
- if (!is_null($value)) { // If value not null, unpack it to unquoted hexadecimal byte-string format
- $value = unpack('H*hex', $value); // we leave it as array, so emulate_bound_params() can detect it
- } // easily and "bind" the param ok.
- } else if ($column->meta_type == 'X') { // MSSQL doesn't cast from int to text, so if text column
- if (is_numeric($value)) { // and is numeric value then cast to string
- $value = array('numstr' => (string)$value); // and put into array, so emulate_bound_params() will know how
- } // to "bind" the param ok, avoiding reverse conversion to number
- } else if ($value === '') {
- if ($column->meta_type == 'I' or $column->meta_type == 'F' or $column->meta_type == 'N') {
- $value = 0; // prevent '' problems in numeric fields
- }
- }
- return $value;
- }
- /**
- * Selectively call mssql_free_result(), avoiding some warnings without using the horrible @
- *
- * @param mssql_resource $resource resource to be freed if possible
- */
- private function free_result($resource) {
- if (!is_bool($resource)) { // true/false resources cannot be freed
- mssql_free_result($resource);
- }
- }
- /**
- * Provides mapping between mssql native data types and moodle_database - database_column_info - ones)
- *
- * @param string $mssql_type native mssql data type
- * @return string 1-char database_column_info data type
- */
- private function mssqltype2moodletype($mssql_type) {
- $type = null;
- switch (strtoupper($mssql_type)) {
- case 'BIT':
- $type = 'L';
- break;
- case 'INT':
- case 'SMALLINT':
- case 'INTEGER':
- case 'BIGINT':
- $type = 'I';
- break;
- case 'DECIMAL':
- case 'REAL':
- case 'FLOAT':
- $type = 'N';
- break;
- case 'VARCHAR':
- case 'NVARCHAR':
- $type = 'C';
- break;
- case 'TEXT':
- case 'NTEXT':
- case 'VARCHAR(MAX)':
- case 'NVARCHAR(MAX)':
- $type = 'X';
- break;
- case 'IMAGE':
- case 'VARBINARY':
- case 'VARBINARY(MAX)':
- $type = 'B';
- break;
- case 'DATETIME':
- $type = 'D';
- break;
- }
- if (!$type) {
- throw new dml_exception('invalidmssqlnativetype', $mssql_type);
- }
- return $type;
- }
- /**
- * Do NOT use in code, to be used by database_manager only!
- * @param string|array $sql query
- * @param array|null $tablenames an array of xmldb table names affected by this request.
- * @return bool true
- * @throws ddl_change_structure_exception A DDL specific exception is thrown for any errors.
- */
- public function change_database_structure($sql, $tablenames = null) {
- $this->get_manager(); // Includes DDL exceptions classes ;-)
- $sqls = (array)$sql;
- try {
- foreach ($sqls as $sql) {
- $this->query_start($sql, null, SQL_QUERY_STRUCTURE);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- }
- } catch (ddl_change_structure_exception $e) {
- $this->reset_caches($tablenames);
- throw $e;
- }
- $this->reset_caches($tablenames);
- return true;
- }
- /**
- * Very ugly hack which emulates bound parameters in queries
- * because the mssql driver doesn't support placeholders natively at all
- */
- protected function emulate_bound_params($sql, array $params=null) {
- if (empty($params)) {
- return $sql;
- }
- // ok, we have verified sql statement with ? and correct number of params
- $parts = array_reverse(explode('?', $sql));
- $return = array_pop($parts);
- foreach ($params as $param) {
- if (is_bool($param)) {
- $return .= (int)$param;
- } else if (is_array($param) && isset($param['hex'])) { // detect hex binary, bind it specially
- $return .= '0x' . $param['hex'];
- } else if (is_array($param) && isset($param['numstr'])) { // detect numerical strings that *must not*
- $return .= "N'{$param['numstr']}'"; // be converted back to number params, but bound as strings
- } else if (is_null($param)) {
- $return .= 'NULL';
- } else if (is_number($param)) { // we can not use is_numeric() because it eats leading zeros from strings like 0045646
- $return .= "'".$param."'"; //fix for MDL-24863 to prevent auto-cast to int.
- } else if (is_float($param)) {
- $return .= $param;
- } else {
- $param = str_replace("'", "''", $param);
- $param = str_replace("\0", "", $param);
- $return .= "N'$param'";
- }
- $return .= array_pop($parts);
- }
- return $return;
- }
- /**
- * Execute general sql query. Should be used only when no other method suitable.
- * Do NOT use this to make changes in db structure, use database_manager methods instead!
- * @param string $sql query
- * @param array $params query parameters
- * @return bool true
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function execute($sql, array $params=null) {
- list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
- $rawsql = $this->emulate_bound_params($sql, $params);
- if (strpos($sql, ';') !== false) {
- throw new coding_exception('moodle_database::execute() Multiple sql statements found or bound parameters not used properly in query!');
- }
- $this->query_start($sql, $params, SQL_QUERY_UPDATE);
- $result = mssql_query($rawsql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- return true;
- }
- /**
- * Get a number of records as a moodle_recordset using a SQL statement.
- *
- * Since this method is a little less readable, use of it should be restricted to
- * code where it's possible there might be large datasets being returned. For known
- * small datasets use get_records_sql - it leads to simpler code.
- *
- * The return type is like:
- * @see function get_recordset.
- *
- * @param string $sql the SQL select query to execute.
- * @param array $params array of sql parameters
- * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
- * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
- * @return moodle_recordset instance
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function get_recordset_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) {
- list($limitfrom, $limitnum) = $this->normalise_limit_from_num($limitfrom, $limitnum);
- if ($limitfrom or $limitnum) {
- if (!$this->supportsoffsetfetch) {
- if ($limitnum >= 1) { // Only apply TOP clause if we have any limitnum (limitfrom offset is handled later).
- $fetch = $limitfrom + $limitnum;
- if (PHP_INT_MAX - $limitnum < $limitfrom) { // Check PHP_INT_MAX overflow.
- $fetch = PHP_INT_MAX;
- }
- $sql = preg_replace('/^([\s(])*SELECT([\s]+(DISTINCT|ALL))?(?!\s*TOP\s*\()/i',
- "\\1SELECT\\2 TOP $fetch", $sql);
- }
- } else {
- $sql = (substr($sql, -1) === ';') ? substr($sql, 0, -1) : $sql;
- // We need order by to use FETCH/OFFSET.
- // Ordering by first column shouldn't break anything if there was no order in the first place.
- if (!strpos(strtoupper($sql), "ORDER BY")) {
- $sql .= " ORDER BY 1";
- }
- $sql .= " OFFSET ".$limitfrom." ROWS ";
- if ($limitnum > 0) {
- $sql .= " FETCH NEXT ".$limitnum." ROWS ONLY";
- }
- }
- }
- list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
- $rawsql = $this->emulate_bound_params($sql, $params);
- $this->query_start($sql, $params, SQL_QUERY_SELECT);
- $result = mssql_query($rawsql, $this->mssql);
- $this->query_end($result);
- if ($limitfrom && !$this->supportsoffsetfetch) { // Skip $limitfrom records.
- if (!@mssql_data_seek($result, $limitfrom)) {
- // Nothing, most probably seek past the end.
- mssql_free_result($result);
- $result = null;
- }
- }
- return $this->create_recordset($result);
- }
- protected function create_recordset($result) {
- return new mssql_native_moodle_recordset($result);
- }
- /**
- * Get a number of records as an array of objects using a SQL statement.
- *
- * Return value is like:
- * @see function get_records.
- *
- * @param string $sql the SQL select query to execute. The first column of this SELECT statement
- * must be a unique value (usually the 'id' field), as it will be used as the key of the
- * returned array.
- * @param array $params array of sql parameters
- * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
- * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
- * @return array of objects, or empty array if no records were found
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function get_records_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) {
- $rs = $this->get_recordset_sql($sql, $params, $limitfrom, $limitnum);
- $results = array();
- foreach ($rs as $row) {
- $id = reset($row);
- if (isset($results[$id])) {
- $colname = key($row);
- debugging("Did you remember to make the first column something unique in your call to get_records? Duplicate value '$id' found in column '$colname'.", DEBUG_DEVELOPER);
- }
- $results[$id] = $row;
- }
- $rs->close();
- return $results;
- }
- /**
- * Selects records and return values (first field) as an array using a SQL statement.
- *
- * @param string $sql The SQL query
- * @param array $params array of sql parameters
- * @return array of values
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function get_fieldset_sql($sql, array $params=null) {
- $rs = $this->get_recordset_sql($sql, $params);
- $results = array();
- foreach ($rs as $row) {
- $results[] = reset($row);
- }
- $rs->close();
- return $results;
- }
- /**
- * Insert new record into database, as fast as possible, no safety checks, lobs not supported.
- * @param string $table name
- * @param mixed $params data record as object or array
- * @param bool $returnit return it of inserted record
- * @param bool $bulk true means repeated inserts expected
- * @param bool $customsequence true if 'id' included in $params, disables $returnid
- * @return bool|int true or new id
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function insert_record_raw($table, $params, $returnid=true, $bulk=false, $customsequence=false) {
- if (!is_array($params)) {
- $params = (array)$params;
- }
- $returning = "";
- $isidentity = false;
- if ($customsequence) {
- if (!isset($params['id'])) {
- throw new coding_exception('moodle_database::insert_record_raw() id field must be specified if custom sequences used.');
- }
- $returnid = false;
- $columns = $this->get_columns($table);
- if (isset($columns['id']) and $columns['id']->auto_increment) {
- $isidentity = true;
- }
- // Disable IDENTITY column before inserting record with id, only if the
- // column is identity, from meta information.
- if ($isidentity) {
- $sql = 'SET IDENTITY_INSERT {' . $table . '} ON'; // Yes, it' ON!!
- list($sql, $xparams, $xtype) = $this->fix_sql_params($sql, null);
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- }
- } else {
- unset($params['id']);
- if ($returnid) {
- $returning = "OUTPUT inserted.id";
- }
- }
- if (empty($params)) {
- throw new coding_exception('moodle_database::insert_record_raw() no fields found.');
- }
- $fields = implode(',', array_keys($params));
- $qms = array_fill(0, count($params), '?');
- $qms = implode(',', $qms);
- $sql = "INSERT INTO {" . $table . "} ($fields) $returning VALUES ($qms)";
- list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
- $rawsql = $this->emulate_bound_params($sql, $params);
- $this->query_start($sql, $params, SQL_QUERY_INSERT);
- $result = mssql_query($rawsql, $this->mssql);
- // Expected results are:
- // - true: insert ok and there isn't returned information.
- // - false: insert failed and there isn't returned information.
- // - resource: insert executed, need to look for returned (output)
- // values to know if the insert was ok or no. Posible values
- // are false = failed, integer = insert ok, id returned.
- $end = false;
- if (is_bool($result)) {
- $end = $result;
- } else if (is_resource($result)) {
- $end = mssql_result($result, 0, 0); // Fetch 1st column from 1st row.
- }
- $this->query_end($end); // End the query with the calculated $end.
- if ($returning !== "") {
- $params['id'] = $end;
- }
- $this->free_result($result);
- if ($customsequence) {
- // Enable IDENTITY column after inserting record with id, only if the
- // column is identity, from meta information.
- if ($isidentity) {
- $sql = 'SET IDENTITY_INSERT {' . $table . '} OFF'; // Yes, it' OFF!!
- list($sql, $xparams, $xtype) = $this->fix_sql_params($sql, null);
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- }
- }
- if (!$returnid) {
- return true;
- }
- return (int)$params['id'];
- }
- /**
- * Insert a record into a table and return the "id" field if required.
- *
- * Some conversions and safety checks are carried out. Lobs are supported.
- * If the return ID isn't required, then this just reports success as true/false.
- * $data is an object containing needed data
- * @param string $table The database table to be inserted into
- * @param object $data A data object with values for one or more fields in the record
- * @param bool $returnid Should the id of the newly created record entry be returned? If this option is not requested then true/false is returned.
- * @return bool|int true or new id
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function insert_record($table, $dataobject, $returnid=true, $bulk=false) {
- $dataobject = (array)$dataobject;
- $columns = $this->get_columns($table);
- if (empty($columns)) {
- throw new dml_exception('ddltablenotexist', $table);
- }
- $cleaned = array();
- foreach ($dataobject as $field => $value) {
- if ($field === 'id') {
- continue;
- }
- if (!isset($columns[$field])) {
- continue;
- }
- $column = $columns[$field];
- $cleaned[$field] = $this->normalise_value($column, $value);
- }
- return $this->insert_record_raw($table, $cleaned, $returnid, $bulk);
- }
- /**
- * Import a record into a table, id field is required.
- * Safety checks are NOT carried out. Lobs are supported.
- *
- * @param string $table name of database table to be inserted into
- * @param object $dataobject A data object with values for one or more fields in the record
- * @return bool true
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function import_record($table, $dataobject) {
- $dataobject = (array)$dataobject;
- $columns = $this->get_columns($table);
- $cleaned = array();
- foreach ($dataobject as $field => $value) {
- if (!isset($columns[$field])) {
- continue;
- }
- $column = $columns[$field];
- $cleaned[$field] = $this->normalise_value($column, $value);
- }
- $this->insert_record_raw($table, $cleaned, false, false, true);
- return true;
- }
- /**
- * Update record in database, as fast as possible, no safety checks, lobs not supported.
- * @param string $table name
- * @param mixed $params data record as object or array
- * @param bool true means repeated updates expected
- * @return bool true
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function update_record_raw($table, $params, $bulk=false) {
- $params = (array)$params;
- if (!isset($params['id'])) {
- throw new coding_exception('moodle_database::update_record_raw() id field must be specified.');
- }
- $id = $params['id'];
- unset($params['id']);
- if (empty($params)) {
- throw new coding_exception('moodle_database::update_record_raw() no fields found.');
- }
- $sets = array();
- foreach ($params as $field=>$value) {
- $sets[] = "$field = ?";
- }
- $params[] = $id; // last ? in WHERE condition
- $sets = implode(',', $sets);
- $sql = "UPDATE {" . $table . "} SET $sets WHERE id = ?";
- list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
- $rawsql = $this->emulate_bound_params($sql, $params);
- $this->query_start($sql, $params, SQL_QUERY_UPDATE);
- $result = mssql_query($rawsql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- return true;
- }
- /**
- * Update a record in a table
- *
- * $dataobject is an object containing needed data
- * Relies on $dataobject having a variable "id" to
- * specify the record to update
- *
- * @param string $table The database table to be checked against.
- * @param object $dataobject An object with contents equal to fieldname=>fieldvalue. Must have an entry for 'id' to map to the table specified.
- * @param bool true means repeated updates expected
- * @return bool true
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function update_record($table, $dataobject, $bulk=false) {
- $dataobject = (array)$dataobject;
- $columns = $this->get_columns($table);
- $cleaned = array();
- foreach ($dataobject as $field => $value) {
- if (!isset($columns[$field])) {
- continue;
- }
- $column = $columns[$field];
- $cleaned[$field] = $this->normalise_value($column, $value);
- }
- return $this->update_record_raw($table, $cleaned, $bulk);
- }
- /**
- * Set a single field in every table record which match a particular WHERE clause.
- *
- * @param string $table The database table to be checked against.
- * @param string $newfield the field to set.
- * @param string $newvalue the value to set the field to.
- * @param string $select A fragment of SQL to be used in a where clause in the SQL call.
- * @param array $params array of sql parameters
- * @return bool true
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function set_field_select($table, $newfield, $newvalue, $select, array $params=null) {
- if ($select) {
- $select = "WHERE $select";
- }
- if (is_null($params)) {
- $params = array();
- }
- // convert params to ? types
- list($select, $params, $type) = $this->fix_sql_params($select, $params);
- // Get column metadata
- $columns = $this->get_columns($table);
- $column = $columns[$newfield];
- $newvalue = $this->normalise_value($column, $newvalue);
- if (is_null($newvalue)) {
- $newfield = "$newfield = NULL";
- } else {
- $newfield = "$newfield = ?";
- array_unshift($params, $newvalue);
- }
- $sql = "UPDATE {" . $table . "} SET $newfield $select";
- list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
- $rawsql = $this->emulate_bound_params($sql, $params);
- $this->query_start($sql, $params, SQL_QUERY_UPDATE);
- $result = mssql_query($rawsql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- return true;
- }
- /**
- * Delete one or more records from a table which match a particular WHERE clause.
- *
- * @param string $table The database table to be checked against.
- * @param string $select A fragment of SQL to be used in a where clause in the SQL call (used to define the selection criteria).
- * @param array $params array of sql parameters
- * @return bool true
- * @throws dml_exception A DML specific exception is thrown for any errors.
- */
- public function delete_records_select($table, $select, array $params=null) {
- if ($select) {
- $select = "WHERE $select";
- }
- $sql = "DELETE FROM {" . $table . "} $select";
- list($sql, $params, $type) = $this->fix_sql_params($sql, $params);
- $rawsql = $this->emulate_bound_params($sql, $params);
- $this->query_start($sql, $params, SQL_QUERY_UPDATE);
- $result = mssql_query($rawsql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- return true;
- }
- public function sql_cast_char2int($fieldname, $text=false) {
- if (!$text) {
- return ' CAST(' . $fieldname . ' AS INT) ';
- } else {
- return ' CAST(' . $this->sql_compare_text($fieldname) . ' AS INT) ';
- }
- }
- public function sql_cast_char2real($fieldname, $text=false) {
- if (!$text) {
- return ' CAST(' . $fieldname . ' AS REAL) ';
- } else {
- return ' CAST(' . $this->sql_compare_text($fieldname) . ' AS REAL) ';
- }
- }
- public function sql_ceil($fieldname) {
- return ' CEILING(' . $fieldname . ')';
- }
- protected function get_collation() {
- if (isset($this->collation)) {
- return $this->collation;
- }
- if (!empty($this->dboptions['dbcollation'])) {
- // perf speedup
- $this->collation = $this->dboptions['dbcollation'];
- return $this->collation;
- }
- // make some default
- $this->collation = 'Latin1_General_CI_AI';
- $sql = "SELECT CAST(DATABASEPROPERTYEX('$this->dbname', 'Collation') AS varchar(255)) AS SQLCollation";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- if ($result) {
- if ($rawcolumn = mssql_fetch_assoc($result)) {
- $this->collation = reset($rawcolumn);
- }
- $this->free_result($result);
- }
- return $this->collation;
- }
- public function sql_equal($fieldname, $param, $casesensitive = true, $accentsensitive = true, $notequal = false) {
- $equalop = $notequal ? '<>' : '=';
- $collation = $this->get_collation();
- if ($casesensitive) {
- $collation = str_replace('_CI', '_CS', $collation);
- } else {
- $collation = str_replace('_CS', '_CI', $collation);
- }
- if ($accentsensitive) {
- $collation = str_replace('_AI', '_AS', $collation);
- } else {
- $collation = str_replace('_AS', '_AI', $collation);
- }
- return "$fieldname COLLATE $collation $equalop $param";
- }
- /**
- * Returns 'LIKE' part of a query.
- *
- * @param string $fieldname usually name of the table column
- * @param string $param usually bound query parameter (?, :named)
- * @param bool $casesensitive use case sensitive search
- * @param bool $accensensitive use accent sensitive search (not all databases support accent insensitive)
- * @param bool $notlike true means "NOT LIKE"
- * @param string $escapechar escape char for '%' and '_'
- * @return string SQL code fragment
- */
- public function sql_like($fieldname, $param, $casesensitive = true, $accentsensitive = true, $notlike = false, $escapechar = '\\') {
- if (strpos($param, '%') !== false) {
- debugging('Potential SQL injection detected, sql_like() expects bound parameters (? or :named)');
- }
- $collation = $this->get_collation();
- if ($casesensitive) {
- $collation = str_replace('_CI', '_CS', $collation);
- } else {
- $collation = str_replace('_CS', '_CI', $collation);
- }
- if ($accentsensitive) {
- $collation = str_replace('_AI', '_AS', $collation);
- } else {
- $collation = str_replace('_AS', '_AI', $collation);
- }
- $LIKE = $notlike ? 'NOT LIKE' : 'LIKE';
- return "$fieldname COLLATE $collation $LIKE $param ESCAPE '$escapechar'";
- }
- public function sql_concat() {
- $arr = func_get_args();
- foreach ($arr as $key => $ele) {
- $arr[$key] = ' CAST(' . $ele . ' AS NVARCHAR(255)) ';
- }
- $s = implode(' + ', $arr);
- if ($s === '') {
- return " '' ";
- }
- return " $s ";
- }
- public function sql_concat_join($separator="' '", $elements=array()) {
- for ($n=count($elements)-1; $n > 0 ; $n--) {
- array_splice($elements, $n, 0, $separator);
- }
- return call_user_func_array(array($this, 'sql_concat'), $elements);
- }
- public function sql_isempty($tablename, $fieldname, $nullablefield, $textfield) {
- if ($textfield) {
- return ' (' . $this->sql_compare_text($fieldname) . " = '') ";
- } else {
- return " ($fieldname = '') ";
- }
- }
- /**
- * Returns the SQL text to be used to calculate the length in characters of one expression.
- * @param string fieldname or expression to calculate its length in characters.
- * @return string the piece of SQL code to be used in the statement.
- */
- public function sql_length($fieldname) {
- return ' LEN(' . $fieldname . ')';
- }
- public function sql_order_by_text($fieldname, $numchars=32) {
- return " CONVERT(varchar({$numchars}), {$fieldname})";
- }
- /**
- * Returns the SQL for returning searching one string for the location of another.
- */
- public function sql_position($needle, $haystack) {
- return "CHARINDEX(($needle), ($haystack))";
- }
- /**
- * 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 int
- * @param mixed $length optional integer or expression evaluating to int
- * @return string sql fragment
- */
- public function sql_substr($expr, $start, $length=false) {
- if (count(func_get_args()) < 2) {
- throw new coding_exception('moodle_database::sql_substr() requires at least two parameters', 'Originaly this function wa
- s only returning name of SQL substring function, it now requires all parameters.');
- }
- if ($length === false) {
- return "SUBSTRING($expr, " . $this->sql_cast_char2int($start) . ", 2^31-1)";
- } else {
- return "SUBSTRING($expr, " . $this->sql_cast_char2int($start) . ", " . $this->sql_cast_char2int($length) . ")";
- }
- }
- /**
- * Does this driver support tool_replace?
- *
- * @since Moodle 2.6.1
- * @return bool
- */
- public function replace_all_text_supported() {
- return true;
- }
- public function session_lock_supported() {
- return true;
- }
- /**
- * Obtain session lock
- * @param int $rowid id of the row with session record
- * @param int $timeout max allowed time to wait for the lock in seconds
- * @return bool success
- */
- public function get_session_lock($rowid, $timeout) {
- if (!$this->session_lock_supported()) {
- return;
- }
- parent::get_session_lock($rowid, $timeout);
- $timeoutmilli = $timeout * 1000;
- $fullname = $this->dbname.'-'.$this->prefix.'-session-'.$rowid;
- // There is one bug in PHP/freetds (both reproducible with mssql_query()
- // and its mssql_init()/mssql_bind()/mssql_execute() alternative) for
- // stored procedures, causing scalar results of the execution
- // to be cast to boolean (true/fals). Here there is one
- // workaround that forces the return of one recordset resource.
- // $sql = "sp_getapplock '$fullname', 'Exclusive', 'Session', $timeoutmilli";
- $sql = "BEGIN
- DECLARE @result INT
- EXECUTE @result = sp_getapplock @Resource='$fullname',
- @LockMode='Exclusive',
- @LockOwner='Session',
- @LockTimeout='$timeoutmilli'
- SELECT @result
- END";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- if ($result) {
- $row = mssql_fetch_row($result);
- if ($row[0] < 0) {
- throw new dml_sessionwait_exception();
- }
- }
- $this->free_result($result);
- }
- public function release_session_lock($rowid) {
- if (!$this->session_lock_supported()) {
- return;
- }
- if (!$this->used_for_db_sessions) {
- return;
- }
- parent::release_session_lock($rowid);
- $fullname = $this->dbname.'-'.$this->prefix.'-session-'.$rowid;
- $sql = "sp_releaseapplock '$fullname', 'Session'";
- $this->query_start($sql, null, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- }
- /**
- * Driver specific start of real database transaction,
- * this can not be used directly in code.
- * @return void
- */
- protected function begin_transaction() {
- // requires database to run with READ_COMMITTED_SNAPSHOT ON
- $sql = "BEGIN TRANSACTION"; // Will be using READ COMMITTED isolation
- $this->query_start($sql, NULL, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- }
- /**
- * Driver specific commit of real database transaction,
- * this can not be used directly in code.
- * @return void
- */
- protected function commit_transaction() {
- $sql = "COMMIT TRANSACTION";
- $this->query_start($sql, NULL, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- }
- /**
- * Driver specific abort of real database transaction,
- * this can not be used directly in code.
- * @return void
- */
- protected function rollback_transaction() {
- $sql = "ROLLBACK TRANSACTION";
- $this->query_start($sql, NULL, SQL_QUERY_AUX);
- $result = mssql_query($sql, $this->mssql);
- $this->query_end($result);
- $this->free_result($result);
- }
- }