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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/>.
/**
* Experimental SQLite specific SQL code generator.
*
* @package core_ddl
* @copyright 2008 Andrei Bautu
* @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 SQLite
/// It extends XMLDBgenerator so everything can be
/// overridden as needed to generate correct SQL.
class sqlite_sql_generator extends sql_generator {
/// Only set values that are different from the defaults present in XMLDBgenerator
/** @var bool To specify if the generator must use some DEFAULT clause to drop defaults.*/
public $drop_default_value_required = true;
/** @var string The DEFAULT clause required to drop defaults.*/
public $drop_default_value = NULL;
/** @var string Template to drop PKs. 'TABLENAME' and 'KEYNAME' will be replaced from this template.*/
public $drop_primary_key = 'ALTER TABLE TABLENAME DROP PRIMARY KEY';
/** @var string Template to drop UKs. 'TABLENAME' and 'KEYNAME' will be replaced from this template.*/
public $drop_unique_key = 'ALTER TABLE TABLENAME DROP KEY KEYNAME';
/** @var string Template to drop FKs. 'TABLENAME' and 'KEYNAME' will be replaced from this template.*/
public $drop_foreign_key = 'ALTER TABLE TABLENAME DROP FOREIGN KEY KEYNAME';
/** @var string To define the default to set for NOT NULLs CHARs without default (null=do nothing).*/
public $default_for_char = '';
/** @var bool To avoid outputting the rest of the field specs, leaving only the name and the sequence_name returned.*/
public $sequence_only = 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 = 'INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL';
/** @var string SQL sentence to drop one index where 'TABLENAME', 'INDEXNAME' keywords are dynamically replaced.*/
public $drop_index_sql = 'ALTER TABLE TABLENAME DROP INDEX INDEXNAME';
/** @var string SQL sentence to rename one index where 'TABLENAME', 'OLDINDEXNAME' and 'NEWINDEXNAME' are dynamically replaced.*/
public $rename_index_sql = null;
/** @var string SQL sentence to rename one key 'TABLENAME', 'OLDKEYNAME' and 'NEWKEYNAME' are dynamically replaced.*/
public $rename_key_sql = null;
/**
* Creates one new XMLDBmysql
*/
public function __construct($mdb) {
parent::__construct($mdb);
}
/**
* 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 ($table instanceof xmldb_table) {
$table = $table->getName();
}
// From http://sqlite.org/autoinc.html
$value = (int)$this->mdb->get_field_sql('SELECT MAX(id) FROM {'.$table.'}');
return array("UPDATE sqlite_sequence SET seq=$value WHERE name='{$this->prefix}{$table}'");
}
/**
* Given one correct xmldb_key, returns its specs
*/
public function getKeySQL($xmldb_table, $xmldb_key) {
$key = '';
switch ($xmldb_key->getType()) {
case XMLDB_KEY_PRIMARY:
if ($this->primary_keys && count($xmldb_key->getFields())>1) {
if ($this->primary_key_name !== null) {
$key = $this->getEncQuoted($this->primary_key_name);
} else {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'pk');
}
$key .= ' PRIMARY KEY (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
}
break;
case XMLDB_KEY_UNIQUE:
if ($this->unique_keys) {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'uk');
$key .= ' UNIQUE (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
}
break;
case XMLDB_KEY_FOREIGN:
case XMLDB_KEY_FOREIGN_UNIQUE:
if ($this->foreign_keys) {
$key = $this->getNameForObject($xmldb_table->getName(), implode(', ', $xmldb_key->getFields()), 'fk');
$key .= ' FOREIGN KEY (' . implode(', ', $this->getEncQuoted($xmldb_key->getFields())) . ')';
$key .= ' REFERENCES ' . $this->getEncQuoted($this->prefix . $xmldb_key->getRefTable());
$key .= ' (' . implode(', ', $this->getEncQuoted($xmldb_key->getRefFields())) . ')';
}
break;
}
return $key;
}
/**
* 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://www.sqlite.org/datatype3.html
if (empty($xmldb_length)) {
$xmldb_length = 10;
}
$dbtype = 'INTEGER(' . $xmldb_length . ')';
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:
$dbtype = 'REAL';
if (!empty($xmldb_length)) {
$dbtype .= '(' . $xmldb_length;
if (!empty($xmldb_decimals)) {
$dbtype .= ',' . $xmldb_decimals;
}
$dbtype .= ')';
}
break;
case XMLDB_TYPE_CHAR:
$dbtype = 'VARCHAR';
if (empty($xmldb_length)) {
$xmldb_length='255';
}
$dbtype .= '(' . $xmldb_length . ')';
break;
case XMLDB_TYPE_BINARY:
$dbtype = 'BLOB';
break;
case XMLDB_TYPE_DATETIME:
$dbtype = 'DATETIME';
default:
case XMLDB_TYPE_TEXT:
$dbtype = 'TEXT';
break;
}
return $dbtype;
}
/**
* Function to emulate full ALTER TABLE which SQLite does not support.
* The function can be used to drop a column ($xmldb_delete_field != null and
* $xmldb_add_field == null), add a column ($xmldb_delete_field == null and
* $xmldb_add_field != null), change/rename a column ($xmldb_delete_field == null
* and $xmldb_add_field == null).
* @param xmldb_table $xmldb_table table to change
* @param xmldb_field $xmldb_add_field column to create/modify (full specification is required)
* @param xmldb_field $xmldb_delete_field column to delete/modify (only name field is required)
* @return array of strings (SQL statements to alter the table structure)
*/
protected function getAlterTableSchema($xmldb_table, $xmldb_add_field=NULL, $xmldb_delete_field=NULL) {
/// Get the quoted name of the table and field
$tablename = $this->getTableName($xmldb_table);
$oldname = $xmldb_delete_field ? $xmldb_delete_field->getName() : NULL;
$newname = $xmldb_add_field ? $xmldb_add_field->getName() : NULL;
if($xmldb_delete_field) {
$xmldb_table->deleteField($oldname);
}
if($xmldb_add_field) {
$xmldb_table->addField($xmldb_add_field);
}
if($oldname) {
// alter indexes
$indexes = $xmldb_table->getIndexes();
foreach($indexes as $index) {
$fields = $index->getFields();
$i = array_search($oldname, $fields);
if($i!==FALSE) {
if($newname) {
$fields[$i] = $newname;
} else {
unset($fields[$i]);
}
$xmldb_table->deleteIndex($index->getName());
if(count($fields)) {
$index->setFields($fields);
$xmldb_table->addIndex($index);
}
}
}
// alter keys
$keys = $xmldb_table->getKeys();
foreach($keys as $key) {
$fields = $key->getFields();
$reffields = $key->getRefFields();
$i = array_search($oldname, $fields);
if($i!==FALSE) {
if($newname) {
$fields[$i] = $newname;
} else {
unset($fields[$i]);
unset($reffields[$i]);
}
$xmldb_table->deleteKey($key->getName());
if(count($fields)) {
$key->setFields($fields);
$key->setRefFields($fields);
$xmldb_table->addkey($key);
}
}
}
}
// prepare data copy
$fields = $xmldb_table->getFields();
foreach ($fields as $key => $field) {
$fieldname = $field->getName();
if($fieldname == $newname && $oldname && $oldname != $newname) {
// field rename operation
$fields[$key] = $this->getEncQuoted($oldname) . ' AS ' . $this->getEncQuoted($newname);
} else {
$fields[$key] = $this->getEncQuoted($field->getName());
}
}
$fields = implode(',', $fields);
$results[] = 'BEGIN TRANSACTION';
$results[] = 'CREATE TEMPORARY TABLE temp_data AS SELECT * FROM ' . $tablename;
$results[] = 'DROP TABLE ' . $tablename;
$results = array_merge($results, $this->getCreateTableSQL($xmldb_table));
$results[] = 'INSERT INTO ' . $tablename . ' SELECT ' . $fields . ' FROM temp_data';
$results[] = 'DROP TABLE temp_data';
$results[] = 'COMMIT';
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) {
return $this->getAlterTableSchema($xmldb_table, $xmldb_field, $xmldb_field);
}
/**
* Given one xmldb_table and one xmldb_key, return the SQL statements needed to add the key to the table
* note that underlying indexes will be added as parametrised by $xxxx_keys and $xxxx_index parameters
*/
public function getAddKeySQL($xmldb_table, $xmldb_key) {
$xmldb_table->addKey($xmldb_key);
return $this->getAlterTableSchema($xmldb_table);
}
/**
* 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) {
return $this->getAlterTableSchema($xmldb_table, $xmldb_field, $xmldb_field);
}
/**
* Given one correct xmldb_field and the new name, returns the SQL statements
* to rename it (inside one array).
*
* @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) {
$oldfield = clone($xmldb_field);
$xmldb_field->setName($newname);
return $this->getAlterTableSchema($xmldb_table, $xmldb_field, $oldfield);
}
/**
* Given one xmldb_table and one xmldb_index, return the SQL statements needed to rename the index in the table
*/
function getRenameIndexSQL($xmldb_table, $xmldb_index, $newname) {
/// Get the real index name
$dbindexname = $this->mdb->get_manager()->find_index_name($xmldb_table, $xmldb_index);
$xmldb_index->setName($newname);
$results = array('DROP INDEX ' . $dbindexname);
$results = array_merge($results, $this->getCreateIndexSQL($xmldb_table, $xmldb_index));
return $results;
}
/**
* Given one xmldb_table and one xmldb_key, return the SQL statements needed to rename the key in the table
* Experimental! Shouldn't be used at all!
*/
public function getRenameKeySQL($xmldb_table, $xmldb_key, $newname) {
$xmldb_table->deleteKey($xmldb_key->getName());
$xmldb_key->setName($newname);
$xmldb_table->addkey($xmldb_key);
return $this->getAlterTableSchema($xmldb_table);
}
/**
* Given one xmldb_table and one xmldb_field, return the SQL statements needed to drop the field from the table.
*
* @param xmldb_table $xmldb_table The table related to $xmldb_field.
* @param xmldb_field $xmldb_field The instance of xmldb_field to create the SQL from.
* @return array The SQL statement for dropping a field from the table.
*/
public function getDropFieldSQL($xmldb_table, $xmldb_field) {
return $this->getAlterTableSchema($xmldb_table, NULL, $xmldb_field);
}
/**
* Given one xmldb_table and one xmldb_index, return the SQL statements needed to drop the index from the table
*/
public function getDropIndexSQL($xmldb_table, $xmldb_index) {
$xmldb_table->deleteIndex($xmldb_index->getName());
return $this->getAlterTableSchema($xmldb_table);
}
/**
* Given one xmldb_table and one xmldb_index, return the SQL statements needed to drop the index from the table
*/
public function getDropKeySQL($xmldb_table, $xmldb_key) {
$xmldb_table->deleteKey($xmldb_key->getName());
return $this->getAlterTableSchema($xmldb_table);
}
/**
* 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) {
return $this->getAlterTableSchema($xmldb_table, $xmldb_field, $xmldb_field);
}
/**
* Returns the code (array of statements) needed to add one comment to the table.
*
* @param xmldb_table $xmldb_table The xmldb_table object instance.
* @return array Array of SQL statements to add one comment to the table.
*/
function getCommentSQL ($xmldb_table) {
return array();
}
/**
* 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) {
// TODO: add introspection code
return false; //No name in use found
}
/**
* Returns an array of reserved words (lowercase) for this DB
* @return array An array of database specific reserved words
*/
public static function getReservedWords() {
/// From http://www.sqlite.org/lang_keywords.html
$reserved_words = array (
'add', 'all', 'alter', 'and', 'as', 'autoincrement',
'between', 'by',
'case', 'check', 'collate', 'column', 'commit', 'constraint', 'create', 'cross',
'default', 'deferrable', 'delete', 'distinct', 'drop',
'else', 'escape', 'except', 'exists',
'foreign', 'from', 'full',
'group',
'having',
'in', 'index', 'inner', 'insert', 'intersect', 'into', 'is', 'isnull',
'join',
'left', 'limit',
'natural', 'not', 'notnull', 'null',
'on', 'or', 'order', 'outer',
'primary',
'references', 'regexp', 'right', 'rollback',
'select', 'set',
'table', 'then', 'to', 'transaction',
'union', 'unique', 'update', 'using',
'values',
'when', 'where'
);
return $reserved_words;
}
/**
* 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;
}
}