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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 pdo database class.
*
* @package core_dml
* @copyright 2008 Andrei Bautu
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
defined('MOODLE_INTERNAL') || die();
require_once(__DIR__.'/pdo_moodle_database.php');
/**
* Experimental pdo database class
*
* @package core_dml
* @copyright 2008 Andrei Bautu
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
class sqlite3_pdo_moodle_database extends pdo_moodle_database {
protected $database_file_extension = '.sq3.php';
/**
* 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 (!extension_loaded('pdo_sqlite') || !extension_loaded('pdo')){
return get_string('sqliteextensionisnotpresentinphp', '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 'sqlite';
}
/**
* 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 'sqlite3';
}
protected function configure_dbconnection() {
// try to protect database file against web access;
// this is required in case that the moodledata folder is web accessible and
// .htaccess is not in place; requires that the database file extension is php
$this->pdb->exec('CREATE TABLE IF NOT EXISTS "<?php die?>" (id int)');
$this->pdb->exec('PRAGMA synchronous=OFF');
$this->pdb->exec('PRAGMA short_column_names=1');
$this->pdb->exec('PRAGMA encoding="UTF-8"');
$this->pdb->exec('PRAGMA case_sensitive_like=0');
$this->pdb->exec('PRAGMA locking_mode=NORMAL');
}
/**
* Attempt to create the database
* @param string $dbhost
* @param string $dbuser
* @param string $dbpass
* @param string $dbname
*
* @return bool success
*/
public function create_database($dbhost, $dbuser, $dbpass, $dbname, array $dboptions=null) {
global $CFG;
$this->dbhost = $dbhost;
$this->dbuser = $dbuser;
$this->dbpass = $dbpass;
$this->dbname = $dbname;
$filepath = $this->get_dbfilepath();
$dirpath = dirname($filepath);
@mkdir($dirpath, $CFG->directorypermissions, true);
return touch($filepath);
}
/**
* Returns the driver-dependent DSN for PDO based on members stored by connect.
* Must be called after connect (or after $dbname, $dbhost, etc. members have been set).
* @return string driver-dependent DSN
*/
protected function get_dsn() {
return 'sqlite:'.$this->get_dbfilepath();
}
/**
* Returns the file path for the database file, computed from dbname and/or dboptions.
* If dboptions['file'] is set, then it is used (use :memory: for in memory database);
* else if dboptions['path'] is set, then the file will be <dboptions path>/<dbname>.sq3.php;
* else if dbhost is set and not localhost, then the file will be <dbhost>/<dbname>.sq3.php;
* else the file will be <moodle data path>/<dbname>.sq3.php
* @return string file path to the SQLite database;
*/
public function get_dbfilepath() {
global $CFG;
if (!empty($this->dboptions['file'])) {
return $this->dboptions['file'];
}
if ($this->dbhost && $this->dbhost != 'localhost') {
$path = $this->dbhost;
} else {
$path = $CFG->dataroot;
}
$path = rtrim($path, '\\/').'/';
if (!empty($this->dbuser)) {
$path .= $this->dbuser.'_';
}
$path .= $this->dbname.'_'.md5($this->dbpass).$this->database_file_extension;
return $path;
}
/**
* 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) {
$tables = array();
$sql = 'SELECT name FROM sqlite_master WHERE type="table" UNION ALL SELECT name FROM sqlite_temp_master WHERE type="table" ORDER BY name';
if ($this->debug) {
$this->debug_query($sql);
}
$rstables = $this->pdb->query($sql);
foreach ($rstables as $table) {
$table = $table['name'];
$table = strtolower($table);
if ($this->prefix !== false && $this->prefix !== '') {
if (strpos($table, $this->prefix) !== 0) {
continue;
}
$table = substr($table, strlen($this->prefix));
}
$tables[$table] = $table;
}
return $tables;
}
/**
* Return table indexes - everything lowercased
* @param string $table The table we want to get indexes from.
* @return array of arrays
*/
public function get_indexes($table) {
$indexes = array();
$sql = 'PRAGMA index_list('.$this->prefix.$table.')';
if ($this->debug) {
$this->debug_query($sql);
}
$rsindexes = $this->pdb->query($sql);
foreach($rsindexes as $index) {
$unique = (boolean)$index['unique'];
$index = $index['name'];
$sql = 'PRAGMA index_info("'.$index.'")';
if ($this->debug) {
$this->debug_query($sql);
}
$rscolumns = $this->pdb->query($sql);
$columns = array();
foreach($rscolumns as $row) {
$columns[] = strtolower($row['name']);
}
$index = strtolower($index);
$indexes[$index]['unique'] = $unique;
$indexes[$index]['columns'] = $columns;
}
return $indexes;
}
/**
* Returns detailed 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();
// get table's CREATE TABLE command (we'll need it for autoincrement fields)
$sql = 'SELECT sql FROM sqlite_master WHERE type="table" AND tbl_name="'.$this->prefix.$table.'"';
if ($this->debug) {
$this->debug_query($sql);
}
$createsql = $this->pdb->query($sql)->fetch();
if (!$createsql) {
return false;
}
$createsql = $createsql['sql'];
$sql = 'PRAGMA table_info("'. $this->prefix.$table.'")';
if ($this->debug) {
$this->debug_query($sql);
}
$rscolumns = $this->pdb->query($sql);
foreach ($rscolumns as $row) {
$columninfo = array(
'name' => strtolower($row['name']), // colum names must be lowercase
'not_null' =>(boolean)$row['notnull'],
'primary_key' => (boolean)$row['pk'],
'has_default' => !is_null($row['dflt_value']),
'default_value' => $row['dflt_value'],
'auto_increment' => false,
'binary' => false,
//'unsigned' => false,
);
$type = explode('(', $row['type']);
$columninfo['type'] = strtolower($type[0]);
if (count($type) > 1) {
$size = explode(',', trim($type[1], ')'));
$columninfo['max_length'] = $size[0];
if (count($size) > 1) {
$columninfo['scale'] = $size[1];
}
}
// SQLite does not have a fixed set of datatypes (ie. it accepts any string as
// datatype in the CREATE TABLE command. We try to guess which type is used here
switch(substr($columninfo['type'], 0, 3)) {
case 'int': // int integer
if ($columninfo['primary_key'] && preg_match('/'.$columninfo['name'].'\W+integer\W+primary\W+key\W+autoincrement/im', $createsql)) {
$columninfo['meta_type'] = 'R';
$columninfo['auto_increment'] = true;
} else {
$columninfo['meta_type'] = 'I';
}
break;
case 'num': // number numeric
case 'rea': // real
case 'dou': // double
case 'flo': // float
$columninfo['meta_type'] = 'N';
break;
case 'var': // varchar
case 'cha': // char
$columninfo['meta_type'] = 'C';
break;
case 'enu': // enums
$columninfo['meta_type'] = 'C';
break;
case 'tex': // text
case 'clo': // clob
$columninfo['meta_type'] = 'X';
break;
case 'blo': // blob
case 'non': // none
$columninfo['meta_type'] = 'B';
$columninfo['binary'] = true;
break;
case 'boo': // boolean
case 'bit': // bit
case 'log': // logical
$columninfo['meta_type'] = 'L';
$columninfo['max_length'] = 1;
break;
case 'tim': // timestamp
$columninfo['meta_type'] = 'T';
break;
case 'dat': // date datetime
$columninfo['meta_type'] = 'D';
break;
}
if ($columninfo['has_default'] && ($columninfo['meta_type'] == 'X' || $columninfo['meta_type']== 'C')) {
// trim extra quotes from text default values
$columninfo['default_value'] = substr($columninfo['default_value'], 1, -1);
}
$structure[$columninfo['name']] = new database_column_info($columninfo);
}
if ($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 in RDBMS 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) {
return $value;
}
/**
* Returns the sql statement with clauses to append used to limit a recordset range.
* @param string $sql the SQL statement to limit.
* @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 $limitfrom is set).
* @return string the SQL statement with limiting clauses
*/
protected function get_limit_clauses($sql, $limitfrom=0, $limitnum=0) {
if ($limitnum) {
$sql .= ' LIMIT '.$limitnum;
if ($limitfrom) {
$sql .= ' OFFSET '.$limitfrom;
}
}
return $sql;
}
/**
* Delete the records from a table where all the given conditions met.
* If conditions not specified, table is truncated.
*
* @param string $table the table to delete from.
* @param array $conditions optional array $fieldname=>requestedvalue with AND in between
* @return returns success.
*/
public function delete_records($table, array $conditions=null) {
if (is_null($conditions)) {
return $this->execute("DELETE FROM {{$table}}");
}
list($select, $params) = $this->where_clause($table, $conditions);
return $this->delete_records_select($table, $select, $params);
}
/**
* Returns the proper SQL to do CONCAT between the elements passed
* Can take many parameters
*
* @param string $element
* @return string
*/
public function sql_concat() {
$elements = func_get_args();
return implode('||', $elements);
}
/**
* Returns the proper SQL to do CONCAT between the elements passed
* with a given separator
*
* @param string $separator
* @param array $elements
* @return string
*/
public function sql_concat_join($separator="' '", $elements=array()) {
// Intersperse $elements in the array.
// Add items to the array on the fly, walking it
// _backwards_ splicing the elements in. The loop definition
// should skip first and last positions.
for ($n=count($elements)-1; $n > 0; $n--) {
array_splice($elements, $n, 0, $separator);
}
return implode('||', $elements);
}
/**
* Returns the SQL text to be used in order to perform one bitwise XOR operation
* between 2 integers.
*
* @param integer int1 first integer in the operation
* @param integer int2 second integer in the operation
* @return string the piece of SQL code to be used in your statement.
*/
public function sql_bitxor($int1, $int2) {
return '( ~' . $this->sql_bitand($int1, $int2) . ' & ' . $this->sql_bitor($int1, $int2) . ')';
}
}