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<?php// This file is part of Moodle - http://moodle.org///// Moodle is free software: you can redistribute it and/or modify// it under the terms of the GNU General Public License as published by// the Free Software Foundation, either version 3 of the License, or// (at your option) any later version.//// Moodle is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the// GNU General Public License for more details.//// You should have received a copy of the GNU General Public License// along with Moodle. If not, see <http://www.gnu.org/licenses/>./*** MSSQL specific SQL code generator.** @package core_ddl* @copyright 1999 onwards Martin Dougiamas http://dougiamas.com* 2001-3001 Eloy Lafuente (stronk7) http://contiento.com* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later*/defined('MOODLE_INTERNAL') || die();require_once($CFG->libdir.'/ddl/sql_generator.php');/*** This class generate SQL code to be used against MSSQL* It extends XMLDBgenerator so everything can be* overridden as needed to generate correct SQL.** @package core_ddl* @copyright 1999 onwards Martin Dougiamas http://dougiamas.com* 2001-3001 Eloy Lafuente (stronk7) http://contiento.com* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later*/class mssql_sql_generator extends sql_generator {// Only set values that are different from the defaults present in XMLDBgenerator/** @var string To be automatically added at the end of each statement. */public $statement_end = "\ngo";/** @var string Proper type for NUMBER(x) in this DB. */public $number_type = 'DECIMAL';/** @var string To define the default to set for NOT NULLs CHARs without default (null=do nothing).*/public $default_for_char = '';/*** @var bool To force the generator if NULL clauses must be specified. It shouldn't be necessary.* note: some mssql drivers require them or everything is created as NOT NULL :-(*/public $specify_nulls = true;/** @var bool True if the generator needs to add extra code to generate the sequence fields.*/public $sequence_extra_code = false;/** @var string The particular name for inline sequences in this generator.*/public $sequence_name = 'IDENTITY(1,1)';/** @var bool To avoid outputting the rest of the field specs, leaving only the name and the sequence_name returned.*/public $sequence_only = false;/** @var bool True if the generator needs to add code for table comments.*/public $add_table_comments = false;/** @var string Characters to be used as concatenation operator.*/public $concat_character = '+';/** @var string SQL sentence to rename one table, both 'OLDNAME' and 'NEWNAME' keywords are dynamically replaced.*/public $rename_table_sql = "sp_rename 'OLDNAME', 'NEWNAME'";/** @var string SQL sentence to rename one column where 'TABLENAME', 'OLDFIELDNAME' and 'NEWFIELDNAME' keywords are dynamically replaced.*/public $rename_column_sql = "sp_rename 'TABLENAME.OLDFIELDNAME', 'NEWFIELDNAME', 'COLUMN'";/** @var string SQL sentence to drop one index where 'TABLENAME', 'INDEXNAME' keywords are dynamically replaced.*/public $drop_index_sql = 'DROP INDEX TABLENAME.INDEXNAME';/** @var string SQL sentence to rename one index where 'TABLENAME', 'OLDINDEXNAME' and 'NEWINDEXNAME' are dynamically replaced.*/public $rename_index_sql = "sp_rename 'TABLENAME.OLDINDEXNAME', 'NEWINDEXNAME', 'INDEX'";/** @var string SQL sentence to rename one key 'TABLENAME', 'OLDKEYNAME' and 'NEWKEYNAME' are dynamically replaced.*/public $rename_key_sql = null;/*** Reset a sequence to the id field of a table.** @param xmldb_table|string $table name of table or the table object.* @return array of sql statements*/public function getResetSequenceSQL($table) {if (is_string($table)) {$table = new xmldb_table($table);}$value = (int)$this->mdb->get_field_sql('SELECT MAX(id) FROM {'. $table->getName() . '}');$sqls = array();// MSSQL has one non-consistent behavior to create the first identity value, depending// if the table has been truncated or no. If you are really interested, you can find the// whole description of the problem at:// http://www.justinneff.com/archive/tag/dbcc-checkidentif ($value == 0) {// truncate to get consistent result from reseed$sqls[] = "TRUNCATE TABLE " . $this->getTableName($table);$value = 1;}// From http://msdn.microsoft.com/en-us/library/ms176057.aspx$sqls[] = "DBCC CHECKIDENT ('" . $this->getTableName($table) . "', RESEED, $value)";return $sqls;}/*** Given one xmldb_table, returns it's correct name, depending of all the parametrization* Overridden to allow change of names in temp tables** @param xmldb_table table whose name we want* @param boolean to specify if the name must be quoted (if reserved word, only!)* @return string the correct name of the table*/public function getTableName(xmldb_table $xmldb_table, $quoted=true) {// Get the name, supporting special mssql names for temp tablesif ($this->temptables->is_temptable($xmldb_table->getName())) {$tablename = $this->temptables->get_correct_name($xmldb_table->getName());} else {$tablename = $this->prefix . $xmldb_table->getName();}// Apply quotes optionallyif ($quoted) {$tablename = $this->getEncQuoted($tablename);}return $tablename;}public function getCreateIndexSQL($xmldb_table, $xmldb_index) {list($indexsql) = parent::getCreateIndexSQL($xmldb_table, $xmldb_index);// Unique indexes need to work-around non-standard SQL server behaviour.if ($xmldb_index->getUnique()) {// Find any nullable columns. We need to add a// WHERE field IS NOT NULL to the index definition for each one.//// For example if you have a unique index on the three columns// (required, option1, option2) where the first one is non-null,// and the others nullable, then the SQL will end up as//// CREATE UNIQUE INDEX index_name ON table_name (required, option1, option2)// WHERE option1 IS NOT NULL AND option2 IS NOT NULL//// The first line comes from parent calls above. The WHERE is added below.$extraconditions = [];foreach ($this->get_nullable_fields_in_index($xmldb_table, $xmldb_index) as $fieldname) {$extraconditions[] = $this->getEncQuoted($fieldname) .' IS NOT NULL';}if ($extraconditions) {$indexsql .= ' WHERE ' . implode(' AND ', $extraconditions);}}return [$indexsql];}/*** Given one correct xmldb_table, returns the SQL statements* to create temporary table (inside one array).** @param xmldb_table $xmldb_table The xmldb_table object instance.* @return array of sql statements*/public function getCreateTempTableSQL($xmldb_table) {$this->temptables->add_temptable($xmldb_table->getName());$sqlarr = $this->getCreateTableSQL($xmldb_table);return $sqlarr;}/*** Given one XMLDB Type, length and decimals, returns the DB proper SQL type.** @param int $xmldb_type The xmldb_type defined constant. XMLDB_TYPE_INTEGER and other XMLDB_TYPE_* constants.* @param int $xmldb_length The length of that data type.* @param int $xmldb_decimals The decimal places of precision of the data type.* @return string The DB defined data type.*/public function getTypeSQL($xmldb_type, $xmldb_length=null, $xmldb_decimals=null) {switch ($xmldb_type) {case XMLDB_TYPE_INTEGER: // From http://msdn.microsoft.com/library/en-us/tsqlref/ts_da-db_7msw.asp?frame=trueif (empty($xmldb_length)) {$xmldb_length = 10;}if ($xmldb_length > 9) {$dbtype = 'BIGINT';} else if ($xmldb_length > 4) {$dbtype = 'INTEGER';} else {$dbtype = 'SMALLINT';}break;case XMLDB_TYPE_NUMBER:$dbtype = $this->number_type;if (!empty($xmldb_length)) {$dbtype .= '(' . $xmldb_length;if (!empty($xmldb_decimals)) {$dbtype .= ',' . $xmldb_decimals;}$dbtype .= ')';}break;case XMLDB_TYPE_FLOAT:$dbtype = 'FLOAT';if (!empty($xmldb_decimals)) {if ($xmldb_decimals < 6) {$dbtype = 'REAL';}}break;case XMLDB_TYPE_CHAR:$dbtype = 'NVARCHAR';if (empty($xmldb_length)) {$xmldb_length='255';}$dbtype .= '(' . $xmldb_length . ') COLLATE database_default';break;case XMLDB_TYPE_TEXT:$dbtype = 'NVARCHAR(MAX) COLLATE database_default';break;case XMLDB_TYPE_BINARY:$dbtype = 'VARBINARY(MAX)';break;case XMLDB_TYPE_DATETIME:$dbtype = 'DATETIME';break;}return $dbtype;}/*** Given one xmldb_table and one xmldb_field, return the SQL statements needed to drop the field from the table.* MSSQL overwrites the standard sentence because it needs to do some extra work dropping the default and* check constraints** @param xmldb_table $xmldb_table The table related to $xmldb_field.* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.* @return array The SQL statement for dropping a field from the table.*/public function getDropFieldSQL($xmldb_table, $xmldb_field) {$results = array();// Get the quoted name of the table and field$tablename = $this->getTableName($xmldb_table);$fieldname = $this->getEncQuoted($xmldb_field->getName());// Look for any default constraint in this field and drop itif ($defaultname = $this->getDefaultConstraintName($xmldb_table, $xmldb_field)) {$results[] = 'ALTER TABLE ' . $tablename . ' DROP CONSTRAINT ' . $defaultname;}// Build the standard alter table drop column$results[] = 'ALTER TABLE ' . $tablename . ' DROP COLUMN ' . $fieldname;return $results;}/*** Given one correct xmldb_field and the new name, returns the SQL statements* to rename it (inside one array).** MSSQL is special, so we overload the function here. It needs to* drop the constraints BEFORE renaming the field** @param xmldb_table $xmldb_table The table related to $xmldb_field.* @param xmldb_field $xmldb_field The instance of xmldb_field to get the renamed field from.* @param string $newname The new name to rename the field to.* @return array The SQL statements for renaming the field.*/public function getRenameFieldSQL($xmldb_table, $xmldb_field, $newname) {$results = array(); //Array where all the sentences will be stored// Although this is checked in database_manager::rename_field() - double check// that we aren't trying to rename one "id" field. Although it could be// implemented (if adding the necessary code to rename sequences, defaults,// triggers... and so on under each getRenameFieldExtraSQL() function, it's// better to forbid it, mainly because this field is the default PK and// in the future, a lot of FKs can be pointing here. So, this field, more// or less, must be considered immutable!if ($xmldb_field->getName() == 'id') {return array();}// We can't call to standard (parent) getRenameFieldSQL() function since it would enclose the field name// with improper quotes in MSSQL: here, we use a stored procedure to rename the field i.e. a column object;// we need to take care about how this stored procedure expects parameters to be "qualified".$rename = str_replace('TABLENAME', $this->getTableName($xmldb_table), $this->rename_column_sql);// Qualifying the column object could require brackets: use them, regardless the column name not being a reserved word.$rename = str_replace('OLDFIELDNAME', '[' . $xmldb_field->getName() . ']', $rename);// The new field name should be passed as the actual name, w/o any quote.$rename = str_replace('NEWFIELDNAME', $newname, $rename);$results[] = $rename;return $results;}/*** Returns the code (array of statements) needed to execute extra statements on table rename.** @param xmldb_table $xmldb_table The xmldb_table object instance.* @param string $newname The new name for the table.* @return array Array of extra SQL statements to rename a table.*/public function getRenameTableExtraSQL($xmldb_table, $newname) {$results = array();return $results;}/*** Given one xmldb_table and one xmldb_field, return the SQL statements needed to alter the field in the table.** @param xmldb_table $xmldb_table The table related to $xmldb_field.* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.* @param string $skip_type_clause The type clause on alter columns, NULL by default.* @param string $skip_default_clause The default clause on alter columns, NULL by default.* @param string $skip_notnull_clause The null/notnull clause on alter columns, NULL by default.* @return string The field altering SQL statement.*/public function getAlterFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause = NULL, $skip_default_clause = NULL, $skip_notnull_clause = NULL) {$results = array(); // To store all the needed SQL commands// Get the quoted name of the table and field$tablename = $xmldb_table->getName();$fieldname = $xmldb_field->getName();// Take a look to field metadata$meta = $this->mdb->get_columns($tablename);$metac = $meta[$fieldname];$oldmetatype = $metac->meta_type;$oldlength = $metac->max_length;$olddecimals = empty($metac->scale) ? null : $metac->scale;$oldnotnull = empty($metac->not_null) ? false : $metac->not_null;//$olddefault = empty($metac->has_default) ? null : strtok($metac->default_value, ':');$typechanged = true; //By default, assume that the column type has changed$lengthchanged = true; //By default, assume that the column length has changed// Detect if we are changing the type of the columnif (($xmldb_field->getType() == XMLDB_TYPE_INTEGER && $oldmetatype == 'I') ||($xmldb_field->getType() == XMLDB_TYPE_NUMBER && $oldmetatype == 'N') ||($xmldb_field->getType() == XMLDB_TYPE_FLOAT && $oldmetatype == 'F') ||($xmldb_field->getType() == XMLDB_TYPE_CHAR && $oldmetatype == 'C') ||($xmldb_field->getType() == XMLDB_TYPE_TEXT && $oldmetatype == 'X') ||($xmldb_field->getType() == XMLDB_TYPE_BINARY && $oldmetatype == 'B')) {$typechanged = false;}// If the new field (and old) specs are for integer, let's be a bit more specific differentiating// types of integers. Else, some combinations can cause things like MDL-21868if ($xmldb_field->getType() == XMLDB_TYPE_INTEGER && $oldmetatype == 'I') {if ($xmldb_field->getLength() > 9) { // Convert our new lenghts to detailed meta types$newmssqlinttype = 'I8';} else if ($xmldb_field->getLength() > 4) {$newmssqlinttype = 'I';} else {$newmssqlinttype = 'I2';}if ($metac->type == 'bigint') { // Convert current DB type to detailed meta type (our metatype is not enough!)$oldmssqlinttype = 'I8';} else if ($metac->type == 'smallint') {$oldmssqlinttype = 'I2';} else {$oldmssqlinttype = 'I';}if ($newmssqlinttype != $oldmssqlinttype) { // Compare new and old meta types$typechanged = true; // Change in meta type means change in type at all effects}}// Detect if we are changing the length of the column, not always necessary to drop defaults// if only the length changes, but it's safe to do it alwaysif ($xmldb_field->getLength() == $oldlength) {$lengthchanged = false;}// If type or length have changed drop the default if existsif ($typechanged || $lengthchanged) {$results = $this->getDropDefaultSQL($xmldb_table, $xmldb_field);}// Some changes of type require multiple alter statements, because mssql lacks direct implicit cast between such types// Here it is the matrix: http://msdn.microsoft.com/en-us/library/ms187928(SQL.90).aspx// Going to store such intermediate alters in array of objects, storing all the info needed$multiple_alter_stmt = array();$targettype = $xmldb_field->getType();if ($targettype == XMLDB_TYPE_TEXT && $oldmetatype == 'I') { // integer to text$multiple_alter_stmt[0] = new stdClass; // needs conversion to varchar$multiple_alter_stmt[0]->type = XMLDB_TYPE_CHAR;$multiple_alter_stmt[0]->length = 255;} else if ($targettype == XMLDB_TYPE_TEXT && $oldmetatype == 'N') { // decimal to text$multiple_alter_stmt[0] = new stdClass; // needs conversion to varchar$multiple_alter_stmt[0]->type = XMLDB_TYPE_CHAR;$multiple_alter_stmt[0]->length = 255;} else if ($targettype == XMLDB_TYPE_TEXT && $oldmetatype == 'F') { // float to text$multiple_alter_stmt[0] = new stdClass; // needs conversion to varchar$multiple_alter_stmt[0]->type = XMLDB_TYPE_CHAR;$multiple_alter_stmt[0]->length = 255;} else if ($targettype == XMLDB_TYPE_INTEGER && $oldmetatype == 'X') { // text to integer$multiple_alter_stmt[0] = new stdClass; // needs conversion to varchar$multiple_alter_stmt[0]->type = XMLDB_TYPE_CHAR;$multiple_alter_stmt[0]->length = 255;$multiple_alter_stmt[1] = new stdClass; // and also needs conversion to decimal$multiple_alter_stmt[1]->type = XMLDB_TYPE_NUMBER; // without decimal positions$multiple_alter_stmt[1]->length = 10;} else if ($targettype == XMLDB_TYPE_NUMBER && $oldmetatype == 'X') { // text to decimal$multiple_alter_stmt[0] = new stdClass; // needs conversion to varchar$multiple_alter_stmt[0]->type = XMLDB_TYPE_CHAR;$multiple_alter_stmt[0]->length = 255;} else if ($targettype == XMLDB_TYPE_FLOAT && $oldmetatype == 'X') { // text to float$multiple_alter_stmt[0] = new stdClass; // needs conversion to varchar$multiple_alter_stmt[0]->type = XMLDB_TYPE_CHAR;$multiple_alter_stmt[0]->length = 255;}// Just prevent default clauses in this type of sentences for mssql and launch the parent oneif (empty($multiple_alter_stmt)) { // Direct implicit conversion allowed, launch it$results = array_merge($results, parent::getAlterFieldSQL($xmldb_table, $xmldb_field, NULL, true, NULL));} else { // Direct implicit conversion forbidden, use the intermediate ones$final_type = $xmldb_field->getType(); // Save final type and length$final_length = $xmldb_field->getLength();foreach ($multiple_alter_stmt as $alter) {$xmldb_field->setType($alter->type); // Put our intermediate type and length and alter to it$xmldb_field->setLength($alter->length);$results = array_merge($results, parent::getAlterFieldSQL($xmldb_table, $xmldb_field, NULL, true, NULL));}$xmldb_field->setType($final_type); // Set the final type and length and alter to it$xmldb_field->setLength($final_length);$results = array_merge($results, parent::getAlterFieldSQL($xmldb_table, $xmldb_field, NULL, true, NULL));}// Finally, process the default clause to add it back if necessaryif ($typechanged || $lengthchanged) {$results = array_merge($results, $this->getCreateDefaultSQL($xmldb_table, $xmldb_field));}// Return resultsreturn $results;}/*** Given one xmldb_table and one xmldb_field, return the SQL statements needed to modify the default of the field in the table.** @param xmldb_table $xmldb_table The table related to $xmldb_field.* @param xmldb_field $xmldb_field The instance of xmldb_field to get the modified default value from.* @return array The SQL statement for modifying the default value.*/public function getModifyDefaultSQL($xmldb_table, $xmldb_field) {// MSSQL is a bit special with default constraints because it implements them as external constraints so// normal ALTER TABLE ALTER COLUMN don't work to change defaults. Because this, we have this method overloaded here$results = array();// Decide if we are going to create/modify or to drop the defaultif ($xmldb_field->getDefault() === null) {$results = $this->getDropDefaultSQL($xmldb_table, $xmldb_field); //Drop but, under some circumstances, re-enable$default_clause = $this->getDefaultClause($xmldb_field);if ($default_clause) { //If getDefaultClause() it must have one default, create it$results = array_merge($results, $this->getCreateDefaultSQL($xmldb_table, $xmldb_field)); //Create/modify}} else {$results = $this->getDropDefaultSQL($xmldb_table, $xmldb_field); //Drop (only if exists)$results = array_merge($results, $this->getCreateDefaultSQL($xmldb_table, $xmldb_field)); //Create/modify}return $results;}/*** Given one xmldb_table and one xmldb_field, return the SQL statements needed to add its default* (usually invoked from getModifyDefaultSQL()** @param xmldb_table $xmldb_table The xmldb_table object instance.* @param xmldb_field $xmldb_field The xmldb_field object instance.* @return array Array of SQL statements to create a field's default.*/public function getCreateDefaultSQL($xmldb_table, $xmldb_field) {// MSSQL is a bit special and it requires the corresponding DEFAULT CONSTRAINT to be dropped$results = array();// Get the quoted name of the table and field$tablename = $this->getTableName($xmldb_table);$fieldname = $this->getEncQuoted($xmldb_field->getName());// Now, check if, with the current field attributes, we have to build one default$default_clause = $this->getDefaultClause($xmldb_field);if ($default_clause) {// We need to build the default (Moodle) default, so do it$sql = 'ALTER TABLE ' . $tablename . ' ADD' . $default_clause . ' FOR ' . $fieldname;$results[] = $sql;}return $results;}/*** Given one xmldb_table and one xmldb_field, return the SQL statements needed to drop its default* (usually invoked from getModifyDefaultSQL()** Note that this method may be dropped in future.** @param xmldb_table $xmldb_table The xmldb_table object instance.* @param xmldb_field $xmldb_field The xmldb_field object instance.* @return array Array of SQL statements to create a field's default.** @todo MDL-31147 Moodle 2.1 - Drop getDropDefaultSQL()*/public function getDropDefaultSQL($xmldb_table, $xmldb_field) {// MSSQL is a bit special and it requires the corresponding DEFAULT CONSTRAINT to be dropped$results = array();// Get the quoted name of the table and field$tablename = $this->getTableName($xmldb_table);$fieldname = $this->getEncQuoted($xmldb_field->getName());// Look for the default contraint and, if found, drop itif ($defaultname = $this->getDefaultConstraintName($xmldb_table, $xmldb_field)) {$results[] = 'ALTER TABLE ' . $tablename . ' DROP CONSTRAINT ' . $defaultname;}return $results;}/*** Given one xmldb_table and one xmldb_field, returns the name of its default constraint in DB* or false if not found* This function should be considered internal and never used outside from generator** @param xmldb_table $xmldb_table The xmldb_table object instance.* @param xmldb_field $xmldb_field The xmldb_field object instance.* @return mixed*/protected function getDefaultConstraintName($xmldb_table, $xmldb_field) {// Get the quoted name of the table and field$tablename = $this->getTableName($xmldb_table);$fieldname = $xmldb_field->getName();// Look for any default constraint in this field and drop itif ($default = $this->mdb->get_record_sql("SELECT object_id, object_name(default_object_id) AS defaultconstraintFROM sys.columnsWHERE object_id = object_id(?)AND name = ?", array($tablename, $fieldname))) {return $default->defaultconstraint;} else {return false;}}/*** Given three strings (table name, list of fields (comma separated) and suffix),* create the proper object name quoting it if necessary.** IMPORTANT: This function must be used to CALCULATE NAMES of objects TO BE CREATED,* NEVER TO GUESS NAMES of EXISTING objects!!!** IMPORTANT: We are overriding this function for the MSSQL generator because objects* belonging to temporary tables aren't searchable in the catalog neither in information* schema tables. So, for temporary tables, we are going to add 4 randomly named "virtual"* fields, so the generated names won't cause concurrency problems. Really nasty hack,* but the alternative involves modifying all the creation table code to avoid naming* constraints for temp objects and that will dupe a lot of code.** @param string $tablename The table name.* @param string $fields A list of comma separated fields.* @param string $suffix A suffix for the object name.* @return string Object's name.*/public function getNameForObject($tablename, $fields, $suffix='') {if ($this->temptables->is_temptable($tablename)) { // Is temp table, inject random field names$random = strtolower(random_string(12)); // 12cc to be split in 4 parts$fields = $fields . ', ' . implode(', ', str_split($random, 3));}return parent::getNameForObject($tablename, $fields, $suffix); // Delegate to parent (common) algorithm}/*** Given one object name and it's type (pk, uk, fk, ck, ix, uix, seq, trg).** (MySQL requires the whole xmldb_table object to be specified, so we add it always)** This is invoked from getNameForObject().* Only some DB have this implemented.** @param string $object_name The object's name to check for.* @param string $type The object's type (pk, uk, fk, ck, ix, uix, seq, trg).* @param string $table_name The table's name to check in* @return bool If such name is currently in use (true) or no (false)*/public function isNameInUse($object_name, $type, $table_name) {switch($type) {case 'seq':case 'trg':case 'pk':case 'uk':case 'fk':case 'ck':if ($check = $this->mdb->get_records_sql("SELECT nameFROM sys.objectsWHERE lower(name) = ?", array(strtolower($object_name)))) {return true;}break;case 'ix':case 'uix':if ($check = $this->mdb->get_records_sql("SELECT nameFROM sys.indexesWHERE lower(name) = ?", array(strtolower($object_name)))) {return true;}break;}return false; //No name in use found}/*** Returns the code (array of statements) needed to add one comment to the table.** @param xmldb_table $xmldb_table The xmldb_table object instance.* @return array Array of SQL statements to add one comment to the table.*/public function getCommentSQL($xmldb_table) {return array();}/*** Adds slashes to string.* @param string $s* @return string The escaped string.*/public function addslashes($s) {// do not use php addslashes() because it depends on PHP quote settings!$s = str_replace("'", "''", $s);return $s;}/*** Returns an array of reserved words (lowercase) for this DB* @return array An array of database specific reserved words*/public static function getReservedWords() {// This file contains the reserved words for MSSQL databases// from http://msdn2.microsoft.com/en-us/library/ms189822.aspx// Should be identical to sqlsrv_native_moodle_database::$reservewords.$reserved_words = array ("add", "all", "alter", "and", "any", "as", "asc", "authorization", "avg", "backup", "begin", "between", "break","browse", "bulk", "by", "cascade", "case", "check", "checkpoint", "close", "clustered", "coalesce", "collate", "column","commit", "committed", "compute", "confirm", "constraint", "contains", "containstable", "continue", "controlrow","convert", "count", "create", "cross", "current", "current_date", "current_time", "current_timestamp", "current_user","cursor", "database", "dbcc", "deallocate", "declare", "default", "delete", "deny", "desc", "disk", "distinct","distributed", "double", "drop", "dummy", "dump", "else", "end", "errlvl", "errorexit", "escape", "except", "exec","execute", "exists", "exit", "external", "fetch", "file", "fillfactor", "floppy", "for", "foreign", "freetext","freetexttable", "from", "full", "function", "goto", "grant", "group", "having", "holdlock", "identity","identity_insert", "identitycol", "if", "in", "index", "inner", "insert", "intersect", "into", "is", "isolation","join", "key", "kill", "left", "level", "like", "lineno", "load", "max", "merge", "min", "mirrorexit", "national","nocheck", "nonclustered", "not", "null", "nullif", "of", "off", "offsets", "on", "once", "only", "open","opendatasource", "openquery", "openrowset", "openxml", "option", "or", "order", "outer", "over", "percent", "perm","permanent", "pipe", "pivot", "plan", "precision", "prepare", "primary", "print", "privileges", "proc", "procedure","processexit", "public", "raiserror", "read", "readtext", "reconfigure", "references", "repeatable", "replication","restore", "restrict", "return", "revert", "revoke", "right", "rollback", "rowcount", "rowguidcol", "rule", "save","schema", "securityaudit", "select", "semantickeyphrasetable", "semanticsimilaritydetailstable","semanticsimilaritytable", "serializable", "session_user", "set", "setuser", "shutdown", "some", "statistics", "sum","system_user", "table", "tablesample", "tape", "temp", "temporary", "textsize", "then", "to", "top", "tran","transaction", "trigger", "truncate", "try_convert", "tsequal", "uncommitted", "union", "unique", "unpivot", "update","updatetext", "use", "user", "values", "varying", "view", "waitfor", "when", "where", "while", "with", "within group","work", "writetext");return $reserved_words;}}