moodle/lib/ddl/oracle_sql_generator.php

655 lines
29 KiB
PHP

<?php // $Id$
///////////////////////////////////////////////////////////////////////////
// //
// NOTICE OF COPYRIGHT //
// //
// Moodle - Modular Object-Oriented Dynamic Learning Environment //
// http://moodle.com //
// //
// Copyright (C) 1999 onwards Martin Dougiamas http://dougiamas.com //
// (C) 2001-3001 Eloy Lafuente (stronk7) http://contiento.com //
// //
// This program 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 2 of the License, or //
// (at your option) any later version. //
// //
// This program 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: //
// //
// http://www.gnu.org/copyleft/gpl.html //
// //
///////////////////////////////////////////////////////////////////////////
require_once($CFG->libdir.'/ddl/sql_generator.php');
/// This class generate SQL code to be used against Oracle
/// It extends XMLDBgenerator so everything can be
/// overriden as needed to generate correct SQL.
class oracle_sql_generator extends sql_generator {
/// Only set values that are different from the defaults present in XMLDBgenerator
public $statement_end = "\n/"; // String to be automatically added at the end of each statement
// Using "/" because the standard ";" isn't good for stored procedures (triggers)
public $number_type = 'NUMBER'; // Proper type for NUMBER(x) in this DB
public $unsigned_allowed = false; // To define in the generator must handle unsigned information
public $default_for_char = ' '; // To define the default to set for NOT NULLs CHARs without default (null=do nothing)
// Using this whitespace here because Oracle doesn't distinguish empty and null! :-(
public $drop_default_value_required = true; //To specify if the generator must use some DEFAULT clause to drop defaults
public $drop_default_value = NULL; //The DEFAULT clause required to drop defaults
public $default_after_null = false; //To decide if the default clause of each field must go after the null clause
public $sequence_extra_code = true; //Does the generator need to add extra code to generate the sequence fields
public $sequence_name = ''; //Particular name for inline sequences in this generator
public $enum_inline_code = false; //Does the generator need to add inline code in the column definition
public $alter_column_sql = 'ALTER TABLE TABLENAME MODIFY (COLUMNSPECS)'; //The SQL template to alter columns
/**
* Creates one new XMLDBoci8po
*/
public function __construct($mdb) {
parent::__construct($mdb);
}
/**
* Reset a sequence to the id field of a table.
* @param string $table name of table
* @return bool true
* @throws dml_exception if error
*/
public function reset_sequence($table) {
if (is_string($table)) {
$tablename = $table;
$xmldb_table = new xmldb_table($tablename);
} else {
$tablename = $table->getName();
$xmldb_table = $table;
}
// From http://www.acs.ilstu.edu/docs/oracle/server.101/b10759/statements_2011.htm
$value = (int)$this->mdb->get_field_sql('SELECT MAX(id) FROM {'.$tablename.'}');
$value++;
$seqname = $this->mdb->get_manager()->find_sequence_name($xmldb_table);
if (!$seqname) {
/// Fallback, seqname not found, something is wrong. Inform and use the alternative getNameForObject() method
$seqname = $this->getNameForObject($table, 'id', 'seq');
}
$this->mdb->change_database_structure("DROP SEQUENCE $seqname");
return $this->mdb->change_database_structure("CREATE SEQUENCE $seqname START WITH $value INCREMENT BY 1 NOMAXVALUE");
}
/**
* Given one correct xmldb_table, returns the SQL statements
* to create temporary table (inside one array)
*/
public function getCreateTempTableSQL($xmldb_table) {
$sqlarr = $this->getCreateTableSQL($xmldb_table);
$sqlarr = preg_replace('/^CREATE TABLE (.*)/s', 'CREATE GLOBAL TEMPORARY TABLE $1 ON COMMIT PRESERVE ROWS', $sqlarr);
return $sqlarr;
}
/**
* Given one correct xmldb_table and the new name, returns the SQL statements
* to drop it (inside one array)
*/
public function getDropTempTableSQL($xmldb_table) {
$sqlarr = $this->getDropTableSQL($xmldb_table);
$tablename = $xmldb_table->getName();
array_unshift($sqlarr, "TRUNCATE TABLE {".$tablename."}"); // oracle requires truncate before being able to drop a temp table
return $sqlarr;
}
/**
* Given one XMLDB Type, lenght and decimals, returns the DB proper SQL type
*/
public function getTypeSQL($xmldb_type, $xmldb_length=null, $xmldb_decimals=null) {
switch ($xmldb_type) {
case XMLDB_TYPE_INTEGER: // From http://www.postgresql.org/docs/7.4/interactive/datatype.html
if (empty($xmldb_length)) {
$xmldb_length = 10;
}
$dbtype = 'NUMBER(' . $xmldb_length . ')';
break;
case XMLDB_TYPE_NUMBER:
$dbtype = $this->number_type;
/// 38 is the max allowed
if ($xmldb_length > 38) {
$xmldb_length = 38;
}
if (!empty($xmldb_length)) {
$dbtype .= '(' . $xmldb_length;
if (!empty($xmldb_decimals)) {
$dbtype .= ',' . $xmldb_decimals;
}
$dbtype .= ')';
}
break;
case XMLDB_TYPE_FLOAT:
$dbtype = 'NUMBER';
break;
case XMLDB_TYPE_CHAR:
$dbtype = 'VARCHAR2';
if (empty($xmldb_length)) {
$xmldb_length='255';
}
$dbtype .= '(' . $xmldb_length . ')';
break;
case XMLDB_TYPE_TEXT:
$dbtype = 'CLOB';
break;
case XMLDB_TYPE_BINARY:
$dbtype = 'BLOB';
break;
case XMLDB_TYPE_DATETIME:
$dbtype = 'DATE';
break;
}
return $dbtype;
}
/**
* Returns the code needed to create one sequence for the xmldb_table and xmldb_field passes
*/
public function getCreateSequenceSQL($xmldb_table, $xmldb_field) {
$results = array();
$sequence_name = $this->getNameForObject($xmldb_table->getName(), $xmldb_field->getName(), 'seq');
$sequence = "CREATE SEQUENCE " . $sequence_name;
$sequence.= "\n START WITH 1";
$sequence.= "\n INCREMENT BY 1";
$sequence.= "\n NOMAXVALUE";
$results[] = $sequence;
$results = array_merge($results, $this->getCreateTriggerSQL ($xmldb_table, $xmldb_field));
return $results;
}
/**
* Returns the code needed to create one trigger for the xmldb_table and xmldb_field passed
*/
public function getCreateTriggerSQL($xmldb_table, $xmldb_field) {
$trigger_name = $this->getNameForObject($xmldb_table->getName(), $xmldb_field->getName(), 'trg');
$sequence_name = $this->getNameForObject($xmldb_table->getName(), $xmldb_field->getName(), 'seq');
$trigger = "CREATE TRIGGER " . $trigger_name;
$trigger.= "\n BEFORE INSERT";
$trigger.= "\nON " . $this->getTableName($xmldb_table);
$trigger.= "\n FOR EACH ROW";
$trigger.= "\nBEGIN";
$trigger.= "\n IF :new." . $this->getEncQuoted($xmldb_field->getName()) . ' IS NULL THEN';
$trigger.= "\n SELECT " . $sequence_name . '.nextval INTO :new.' . $this->getEncQuoted($xmldb_field->getName()) . " FROM dual;";
$trigger.= "\n END IF;";
$trigger.= "\nEND;";
return array($trigger);
}
/**
* Returns the code needed to drop one sequence for the xmldb_table and xmldb_field passed
* Can, optionally, specify if the underlying trigger will be also dropped
*/
public function getDropSequenceSQL($xmldb_table, $xmldb_field, $include_trigger=false) {
$result = array();
if ($sequence_name = $this->getSequenceFromDB($xmldb_table)) {
$result[] = "DROP SEQUENCE " . $sequence_name;
}
if ($trigger_name = $this->getTriggerFromDB($xmldb_table) && $include_trigger) {
$result[] = "DROP TRIGGER " . $trigger_name;
}
return $result;
}
/**
* Returns the code (in array) needed to add one comment to the table
*/
function getCommentSQL ($xmldb_table) {
$comment = "COMMENT ON TABLE " . $this->getTableName($xmldb_table);
$comment.= " IS '" . $this->addslashes(substr($xmldb_table->getComment(), 0, 250)) . "'";
return array($comment);
}
/**
* Returns the code (array of statements) needed to execute extra statements on table drop
*/
public function getDropTableExtraSQL($xmldb_table) {
$xmldb_field = new xmldb_field('id'); // Fields having sequences should be exclusively, id.
return $this->getDropSequenceSQL($xmldb_table, $xmldb_field, false);
}
/**
* Returns the code (array of statements) needed to execute extra statements on table rename
*/
public function getRenameTableExtraSQL($xmldb_table, $newname) {
$results = array();
$xmldb_field = new xmldb_field('id'); // Fields having sequences should be exclusively, id.
$oldseqname = $this->getSequenceFromDB($xmldb_table);
$newseqname = $this->getNameForObject($newname, $xmldb_field->getName(), 'seq');
/// Rename de sequence
$results[] = 'RENAME ' . $oldseqname . ' TO ' . $newseqname;
$oldtriggername = $this->getTriggerFromDB($xmldb_table);
$newtriggername = $this->getNameForObject($newname, $xmldb_field->getName(), 'trg');
/// Drop old trigger
$results[] = "DROP TRIGGER " . $oldtriggername;
$newt = new xmldb_table($newname); /// Temp table for trigger code generation
/// Create new trigger
$results = array_merge($results, $this->getCreateTriggerSQL($newt, $xmldb_field));
/// Rename all the check constraints in the table
$oldtablename = $this->getTableName($xmldb_table);
$newtablename = $this->getTableName($newt);
$oldconstraintprefix = $this->getNameForObject($xmldb_table->getName(), '');
$newconstraintprefix = $this->getNameForObject($newt->getName(), '', '');
if ($constraints = $this->getCheckConstraintsFromDB($xmldb_table)) {
foreach ($constraints as $constraint) {
/// Drop the old constraint
$results[] = 'ALTER TABLE ' . $newtablename . ' DROP CONSTRAINT ' . $constraint->name;
}
}
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needded to alter the field in the table
* Oracle has some severe limits:
* - clob and blob fields doesn't allow type to be specified
* - error is dropped if the null/not null clause is specified and hasn't changed
* - changes in precision/decimals of numeric fields drop an ORA-1440 error
*/
public function getAlterFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause = NULL, $skip_default_clause = NULL, $skip_notnull_clause = NULL) {
$skip_type_clause = is_null($skip_type_clause) ? $this->alter_column_skip_type : $skip_type_clause;
$skip_default_clause = is_null($skip_default_clause) ? $this->alter_column_skip_default : $skip_default_clause;
$skip_notnull_clause = is_null($skip_notnull_clause) ? $this->alter_column_skip_notnull : $skip_notnull_clause;
$results = array(); /// To store all the needed SQL commands
/// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$fieldname = $xmldb_field->getName();
/// Take a look to field metadata
$meta = $this->mdb->get_columns($xmldb_table->getName(), false);
$metac = $meta[$fieldname];
$oldmetatype = $metac->meta_type;
$oldlength = $metac->max_length;
/// To calculate the oldlength if the field is numeric, we need to perform one extra query
/// because ADOdb has one bug here. http://phplens.com/lens/lensforum/msgs.php?id=15883
if ($oldmetatype == 'N') {
$uppertablename = strtoupper($tablename);
$upperfieldname = strtoupper($fieldname);
if ($col = $this->mdb->get_record_sql("SELECT cname, precision
FROM col
WHERE tname = ? AND cname = ?",
array($uppertablename, $upperfieldname))) {
$oldlength = $col->precision;
}
}
$olddecimals = empty($metac->scale) ? null : $metac->scale;
$oldnotnull = empty($metac->not_null) ? false : $metac->not_null;
$olddefault = empty($metac->default_value) || strtoupper($metac->default_value) == 'NULL' ? null : $metac->default_value;
$typechanged = true; //By default, assume that the column type has changed
$precisionchanged = true; //By default, assume that the column precision has changed
$decimalchanged = true; //By default, assume that the column decimal has changed
$defaultchanged = true; //By default, assume that the column default has changed
$notnullchanged = true; //By default, assume that the column notnull has changed
$from_temp_fields = false; //By default don't assume we are going to use temporal fields
/// Detect if we are changing the type of the column
if (($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')) {
$typechanged = false;
}
/// Detect if precision has changed
if (($xmldb_field->getType() == XMLDB_TYPE_TEXT) ||
($xmldb_field->getType() == XMLDB_TYPE_BINARY) ||
($oldlength == -1) ||
($xmldb_field->getLength() == $oldlength)) {
$precisionchanged = false;
}
/// Detect if decimal has changed
if (($xmldb_field->getType() == XMLDB_TYPE_INTEGER) ||
($xmldb_field->getType() == XMLDB_TYPE_CHAR) ||
($xmldb_field->getType() == XMLDB_TYPE_TEXT) ||
($xmldb_field->getType() == XMLDB_TYPE_BINARY) ||
(!$xmldb_field->getDecimals()) ||
(!$olddecimals) ||
($xmldb_field->getDecimals() == $olddecimals)) {
$decimalchanged = false;
}
/// Detect if we are changing the default
if (($xmldb_field->getDefault() === null && $olddefault === null) ||
($xmldb_field->getDefault() === $olddefault) || //Check both equality and
("'" . $xmldb_field->getDefault() . "'" === $olddefault)) { //Equality with quotes because ADOdb returns the default with quotes
$defaultchanged = false;
}
/// Detect if we are changing the nullability
if (($xmldb_field->getNotnull() === $oldnotnull)) {
$notnullchanged = false;
}
/// If type has changed or precision or decimal has changed and we are in one numeric field
/// - create one temp column with the new specs
/// - fill the new column with the values from the old one
/// - drop the old column
/// - rename the temp column to the original name
if (($typechanged) || (($oldmetatype == 'N' || $oldmetatype == 'I') && ($precisionchanged || $decimalchanged))) {
$tempcolname = $xmldb_field->getName() . '_alter_column_tmp';
/// Prevent temp field to have both NULL/NOT NULL and DEFAULT constraints
$skip_notnull_clause = true;
$skip_default_clause = true;
$xmldb_field->setName($tempcolname);
/// Create the temporal column
$results = array_merge($results, $this->getAddFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause, $skip_type_clause, $skip_notnull_clause));
/// Copy contents from original col to the temporal one
$results[] = 'UPDATE ' . $tablename . ' SET ' . $tempcolname . ' = ' . $fieldname;
/// Drop the old column
$xmldb_field->setName($fieldname); //Set back the original field name
$results = array_merge($results, $this->getDropFieldSQL($xmldb_table, $xmldb_field));
/// Rename the temp column to the original one
$results[] = 'ALTER TABLE ' . $tablename . ' RENAME COLUMN ' . $tempcolname . ' TO ' . $fieldname;
/// Mark we have performed one change based in temp fields
$from_temp_fields = true;
/// Re-enable the notnull and default sections so the general AlterFieldSQL can use it
$skip_notnull_clause = false;
$skip_default_clause = false;
/// Dissable the type section because we have done it with the temp field
$skip_type_clause = true;
/// If new field is nullable, nullability hasn't changed
if (!$xmldb_field->getNotnull()) {
$notnullchanged = false;
}
/// If new field hasn't default, default hasn't changed
if ($xmldb_field->getDefault() === null) {
$defaultchanged = false;
}
}
/// If type and precision and decimals hasn't changed, prevent the type clause
if (!$typechanged && !$precisionchanged && !$decimalchanged) {
$skip_type_clause = true;
}
/// If NULL/NOT NULL hasn't changed
/// prevent null clause to be specified
if (!$notnullchanged) {
$skip_notnull_clause = true; /// Initially, prevent the notnull clause
/// But, if we have used the temp field and the new field is not null, then enforce the not null clause
if ($from_temp_fields && $xmldb_field->getNotnull()) {
$skip_notnull_clause = false;
}
}
/// If default hasn't changed
/// prevent default clause to be specified
if (!$defaultchanged) {
$skip_default_clause = true; /// Initially, prevent the default clause
/// But, if we have used the temp field and the new field has default clause, then enforce the default clause
if ($from_temp_fields) {
$default_clause = $this->getDefaultClause($xmldb_field);
if ($default_clause) {
$skip_notnull_clause = false;
}
}
}
/// If arriving here, something is not being skiped (type, notnull, default), calculate the standar AlterFieldSQL
if (!$skip_type_clause || !$skip_notnull_clause || !$skip_default_clause) {
$results = array_merge($results, parent::getAlterFieldSQL($xmldb_table, $xmldb_field, $skip_type_clause, $skip_default_clause, $skip_notnull_clause));
return $results;
}
/// Finally return results
return $results;
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needded to drop its enum
* (usually invoked from getModifyEnumSQL()
*
* TODO: Moodle 2.1 - drop in Moodle 2.1
*/
public function getDropEnumSQL($xmldb_table, $xmldb_field) {
/// Let's introspect to know the real name of the check constraint
if ($check_constraints = $this->getCheckConstraintsFromDB($xmldb_table, $xmldb_field)) {
$check_constraint = array_shift($check_constraints); /// Get the 1st (should be only one)
$constraint_name = strtolower($check_constraint->name); /// Extract the REAL name
/// All we have to do is to drop the check constraint
return array('ALTER TABLE ' . $this->getTableName($xmldb_table) .
' DROP CONSTRAINT ' . $constraint_name);
} else { /// Constraint not found. Nothing to do
return array();
}
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needded to create its default
* (usually invoked from getModifyDefaultSQL()
*/
public function getCreateDefaultSQL($xmldb_table, $xmldb_field) {
/// Just a wrapper over the getAlterFieldSQL() function for Oracle that
/// is capable of handling defaults
return $this->getAlterFieldSQL($xmldb_table, $xmldb_field);
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needded to drop its default
* (usually invoked from getModifyDefaultSQL()
*/
public function getDropDefaultSQL($xmldb_table, $xmldb_field) {
/// Just a wrapper over the getAlterFieldSQL() function for Oracle that
/// is capable of handling defaults
return $this->getAlterFieldSQL($xmldb_table, $xmldb_field);
}
/**
* Given one xmldb_table returns one array with all the check constrainsts
* in the table (fetched from DB)
* Optionally the function allows one xmldb_field to be specified in
* order to return only the check constraints belonging to one field.
* Each element contains the name of the constraint and its description
* If no check constraints are found, returns an empty array
*
* TODO: Moodle 2.1 - drop in Moodle 2.1
*/
public function getCheckConstraintsFromDB($xmldb_table, $xmldb_field = null) {
$results = array();
$tablename = strtoupper($this->getTableName($xmldb_table));
if ($constraints = $this->mdb->get_records_sql("SELECT lower(c.constraint_name) AS name, c.search_condition AS description
FROM user_constraints c
WHERE c.table_name = ?
AND c.constraint_type = 'C'
AND c.constraint_name not like 'SYS%'",
array($tablename))) {
foreach ($constraints as $constraint) {
$results[$constraint->name] = $constraint;
}
}
/// Filter by the required field if specified
if ($xmldb_field) {
$filtered_results = array();
$filter = $xmldb_field->getName();
/// Lets clean a bit each constraint description, looking for the filtered field
foreach ($results as $key => $result) {
/// description starts by "$filter IN" assume it's a constraint beloging to the field
if (preg_match("/^{$filter} IN/i", $result->description)) {
$filtered_results[$key] = $result;
}
}
/// Assign filtered results to the final results array
$results = $filtered_results;
}
return $results;
}
/**
* Given one xmldb_table returns one string with the sequence of the table
* in the table (fetched from DB)
* The sequence name for oracle is calculated by looking the corresponding
* trigger and retrieving the sequence name from it (because sequences are
* independent elements)
* If no sequence is found, returns false
*/
public function getSequenceFromDB($xmldb_table) {
$tablename = strtoupper($this->getTableName($xmldb_table));
$prefixupper = strtoupper($this->prefix);
$sequencename = false;
if ($trigger = $this->mdb->get_record_sql("SELECT trigger_name, trigger_body
FROM user_triggers
WHERE table_name = ? AND trigger_name LIKE ?",
array($tablename, "{$prefixupper}%_ID%_TRG"))) {
/// If trigger found, regexp it looking for the sequence name
preg_match('/.*SELECT (.*)\.nextval/i', $trigger->trigger_body, $matches);
if (isset($matches[1])) {
$sequencename = $matches[1];
}
}
return $sequencename;
}
/**
* Given one xmldb_table returns one string with the trigger
* in the table (fetched from DB)
* If no trigger is found, returns false
*/
public function getTriggerFromDB($xmldb_table) {
$tablename = strtoupper($this->getTableName($xmldb_table));
$prefixupper = strtoupper($this->prefix);
$triggername = false;
if ($trigger = $this->mdb->get_record_sql("SELECT trigger_name, trigger_body
FROM user_triggers
WHERE table_name = ? AND trigger_name LIKE ?",
array($tablename, "{$prefixupper}%_ID%_TRG"))) {
$triggername = $trigger->trigger_name;
}
return $triggername;
}
/**
* Given one object name and it's type (pk, uk, fk, ck, ix, uix, seq, trg)
* return if such name is currently in use (true) or no (false)
* (invoked from getNameForObject()
*/
public function isNameInUse($object_name, $type, $table_name) {
switch($type) {
case 'ix':
case 'uix':
case 'seq':
case 'trg':
if ($check = $this->mdb->get_records_sql("SELECT object_name
FROM user_objects
WHERE lower(object_name) = ?", array(strtolower($object_name)))) {
return true;
}
break;
case 'pk':
case 'uk':
case 'fk':
case 'ck':
if ($check = $this->mdb->get_records_sql("SELECT constraint_name
FROM user_constraints
WHERE lower(constraint_name) = ?", array(strtolower($object_name)))) {
return true;
}
break;
}
return false; //No name in use found
}
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
*/
public static function getReservedWords() {
/// This file contains the reserved words for Oracle databases
/// from http://download-uk.oracle.com/docs/cd/B10501_01/server.920/a96540/ap_keywd.htm
$reserved_words = array (
'access', 'add', 'all', 'alter', 'and', 'any',
'as', 'asc', 'audit', 'between', 'by', 'char',
'check', 'cluster', 'column', 'comment',
'compress', 'connect', 'create', 'current',
'date', 'decimal', 'default', 'delete', 'desc',
'distinct', 'drop', 'else', 'exclusive', 'exists',
'file', 'float', 'for', 'from', 'grant', 'group',
'having', 'identified', 'immediate', 'in',
'increment', 'index', 'initial', 'insert',
'integer', 'intersect', 'into', 'is', 'level',
'like', 'lock', 'long', 'maxextents', 'minus',
'mlslabel', 'mode', 'modify', 'noaudit',
'nocompress', 'not', 'nowait', 'null', 'number',
'of', 'offline', 'on', 'online', 'option', 'or',
'order', 'pctfree', 'prior', 'privileges',
'public', 'raw', 'rename', 'resource', 'revoke',
'row', 'rowid', 'rownum', 'rows', 'select',
'session', 'set', 'share', 'size', 'smallint',
'start', 'successful', 'synonym', 'sysdate',
'table', 'then', 'to', 'trigger', 'uid', 'union',
'unique', 'update', 'user', 'validate', 'values',
'varchar', 'varchar2', 'view', 'whenever',
'where', 'with'
);
return $reserved_words;
}
}
?>