File: /home/mbp/domains/mbp.ac.th/public_html/biology/lib/dml/mssql_native_moodle_database.php
<?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;
}
/**
* 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);
}
}