Remove Oracle driver based on PDO_OCI extension

3 files changed, 367 insertions, 629 deletions

diff --git a/program/lib/Roundcube/rcube_db.php b/program/lib/Roundcube/rcube_db.php
index 5a2ad038c..1e6a206da 100644
--- a/program/lib/Roundcube/rcube_db.php
+++ b/program/lib/Roundcube/rcube_db.php
@@ -70,6 +70,7 @@ class rcube_db
             'dblib'   => 'mssql',
             'mysqli'  => 'mysql',
             'oci'     => 'oracle',
+            'oci8'    => 'oracle',
         );
 
         $driver = isset($driver_map[$driver]) ? $driver_map[$driver] : $driver;
diff --git a/program/lib/Roundcube/rcube_db_oci8.php b/program/lib/Roundcube/rcube_db_oci8.php
deleted file mode 100644
index 2f94c1825..000000000
--- a/program/lib/Roundcube/rcube_db_oci8.php
+++ /dev/null
@@ -1,599 +0,0 @@
-<?php
-
-/**
- +-----------------------------------------------------------------------+
- | This file is part of the Roundcube Webmail client                     |
- | Copyright (C) 2011-2014, Kolab Systems AG                             |
- |                                                                       |
- | Licensed under the GNU General Public License version 3 or            |
- | any later version with exceptions for skins & plugins.                |
- | See the README file for a full license statement.                     |
- |                                                                       |
- | PURPOSE:                                                              |
- |   Database wrapper class that implements database functions           |
- |   for Oracle database using OCI8 extension                            |
- +-----------------------------------------------------------------------+
- | Author: Aleksander Machniak <machniak@kolabsys.com>                   |
- +-----------------------------------------------------------------------+
-*/
-
-/**
- * Database independent query interface
- *
- * @package    Framework
- * @subpackage Database
- */
-class rcube_db_oci8 extends rcube_db
-{
-    public $db_provider = 'oracle';
-
-
-    /**
-     * Create connection instance
-     */
-    protected function conn_create($dsn)
-    {
-        // Get database specific connection options
-        $dsn_options = $this->dsn_options($dsn);
-
-        $function = $this->db_pconn ? 'oci_pconnect' : 'oci_connect';
-
-        if (!function_exists($function)) {
-            $this->db_error     = true;
-            $this->db_error_msg = 'OCI8 extension not loaded. See http://php.net/manual/en/book.oci8.php';
-
-            rcube::raise_error(array('code' => 500, 'type' => 'db',
-                'line' => __LINE__, 'file' => __FILE__,
-                'message' => $this->db_error_msg), true, false);
-
-            return;
-        }
-
-        // connect
-        $dbh = @$function($dsn['username'], $dsn['password'], $dsn_options['database'], $dsn_options['charset']);
-
-        if (!$dbh) {
-            $error              = oci_error();
-            $this->db_error     = true;
-            $this->db_error_msg = $error['message'];
-
-            rcube::raise_error(array('code' => 500, 'type' => 'db',
-                'line' => __LINE__, 'file' => __FILE__,
-                'message' => $this->db_error_msg), true, false);
-
-            return;
-        }
-
-        // configure session
-        $this->conn_configure($dsn, $dbh);
-
-        return $dbh;
-    }
-
-    /**
-     * Driver-specific configuration of database connection
-     *
-     * @param array $dsn DSN for DB connections
-     * @param PDO   $dbh Connection handler
-     */
-    protected function conn_configure($dsn, $dbh)
-    {
-        $init_queries = array(
-            "ALTER SESSION SET nls_date_format = 'YYYY-MM-DD'",
-            "ALTER SESSION SET nls_timestamp_format = 'YYYY-MM-DD HH24:MI:SS'",
-        );
-
-        foreach ($init_queries as $query) {
-            $stmt = oci_parse($dbh, $query);
-            oci_execute($stmt);
-        }
-    }
-
-    /**
-     * Connection state checker
-     *
-     * @return boolean True if in connected state
-     */
-    public function is_connected()
-    {
-        return empty($this->dbh) ? false : $this->db_connected;
-    }
-
-    /**
-     * Execute a SQL query with limits
-     *
-     * @param string $query   SQL query to execute
-     * @param int    $offset  Offset for LIMIT statement
-     * @param int    $numrows Number of rows for LIMIT statement
-     * @param array  $params  Values to be inserted in query
-     *
-     * @return PDOStatement|bool Query handle or False on error
-     */
-    protected function _query($query, $offset, $numrows, $params)
-    {
-        $query = ltrim($query);
-
-        $this->db_connect($this->dsn_select($query), true);
-
-        // check connection before proceeding
-        if (!$this->is_connected()) {
-            return $this->last_result = false;
-        }
-
-        if ($numrows || $offset) {
-            $query = $this->set_limit($query, $numrows, $offset);
-        }
-
-        // replace self::DEFAULT_QUOTE with driver-specific quoting
-        $query = $this->query_parse($query);
-
-        // Because in Roundcube we mostly use queries that are
-        // executed only once, we will not use prepared queries
-        $pos  = 0;
-        $idx  = 0;
-        $args = array();
-
-        if (count($params)) {
-            while ($pos = strpos($query, '?', $pos)) {
-                if ($query[$pos+1] == '?') {  // skip escaped '?'
-                    $pos += 2;
-                }
-                else {
-                    $val = $this->quote($params[$idx++]);
-
-                    // long strings are not allowed inline, need to be parametrized
-                    if (strlen($val) > 4000) {
-                        $key = ':param' . (count($args) + 1);
-                        $args[$key] = $params[$idx-1];
-                        $val = $key;
-                    }
-
-                    unset($params[$idx-1]);
-                    $query = substr_replace($query, $val, $pos, 1);
-                    $pos += strlen($val);
-                }
-            }
-        }
-
-        // replace escaped '?' back to normal, see self::quote()
-        $query = str_replace('??', '?', $query);
-        $query = rtrim($query, " \t\n\r\0\x0B;");
-
-        // log query
-        $this->debug($query);
-
-        // destroy reference to previous result
-        $this->last_result  = null;
-        $this->db_error_msg = null;
-
-        // prepare query
-        $result = @oci_parse($this->dbh, $query);
-        $mode   = $this->in_transaction ? OCI_NO_AUTO_COMMIT : OCI_COMMIT_ON_SUCCESS;
-
-        if ($result) {
-            foreach ($args as $param => $arg) {
-                oci_bind_by_name($result, $param, $args[$param], -1, SQLT_LNG);
-            }
-        }
-
-        // execute query
-        if (!$result || !@oci_execute($result, $mode)) {
-            $result = $this->handle_error($query, $result);
-        }
-
-        return $this->last_result = $result;
-    }
-
-    /**
-     * Helper method to handle DB errors.
-     * This by default logs the error but could be overriden by a driver implementation
-     *
-     * @param string Query that triggered the error
-     * @return mixed Result to be stored and returned
-     */
-    protected function handle_error($query, $result = null)
-    {
-        $error = oci_error(is_resource($result) ? $result : $this->dbh);
-
-        // @TODO: Find error codes for key errors
-        if (empty($this->options['ignore_key_errors']) || !in_array($error['code'], array('23000', '23505'))) {
-            $this->db_error = true;
-            $this->db_error_msg = sprintf('[%s] %s', $error['code'], $error['message']);
-
-            rcube::raise_error(array('code' => 500, 'type' => 'db',
-                'line' => __LINE__, 'file' => __FILE__,
-                'message' => $this->db_error_msg . " (SQL Query: $query)"
-                ), true, false);
-        }
-
-        return false;
-    }
-
-    /**
-     * Get last inserted record ID
-     *
-     * @param string $table Table name (to find the incremented sequence)
-     *
-     * @return mixed ID or false on failure
-     */
-    public function insert_id($table = null)
-    {
-        if (!$this->db_connected || $this->db_mode == 'r' || empty($table)) {
-            return false;
-        }
-
-        $sequence = $this->quote_identifier($this->sequence_name($table));
-        $result   = $this->query("SELECT $sequence.currval FROM dual");
-        $result   = $this->fetch_array($result);
-
-        return $result[0] ?: false;
-    }
-
-    /**
-     * Get number of affected rows for the last query
-     *
-     * @param mixed $result Optional query handle
-     *
-     * @return int Number of (matching) rows
-     */
-    public function affected_rows($result = null)
-    {
-        if ($result || ($result === null && ($result = $this->last_result))) {
-            return oci_num_rows($result);
-        }
-
-        return 0;
-    }
-
-    /**
-     * Get number of rows for a SQL query
-     * If no query handle is specified, the last query will be taken as reference
-     *
-     * @param mixed $result Optional query handle
-     * @return mixed   Number of rows or false on failure
-     * @deprecated This method shows very poor performance and should be avoided.
-     */
-    public function num_rows($result = null)
-    {
-        // not implemented
-        return false;
-    }
-
-    /**
-     * Get an associative array for one row
-     * If no query handle is specified, the last query will be taken as reference
-     *
-     * @param mixed $result Optional query handle
-     *
-     * @return mixed Array with col values or false on failure
-     */
-    public function fetch_assoc($result = null)
-    {
-        return $this->_fetch_row($result, OCI_ASSOC);
-    }
-
-    /**
-     * Get an index array for one row
-     * If no query handle is specified, the last query will be taken as reference
-     *
-     * @param mixed $result Optional query handle
-     *
-     * @return mixed Array with col values or false on failure
-     */
-    public function fetch_array($result = null)
-    {
-        return $this->_fetch_row($result, OCI_NUM);
-    }
-
-    /**
-     * Get col values for a result row
-     *
-     * @param mixed $result Optional query handle
-     * @param int   $mode   Fetch mode identifier
-     *
-     * @return mixed Array with col values or false on failure
-     */
-    protected function _fetch_row($result, $mode)
-    {
-        if ($result || ($result === null && ($result = $this->last_result))) {
-            return oci_fetch_array($result, $mode + OCI_RETURN_NULLS + OCI_RETURN_LOBS);
-        }
-
-        return false;
-    }
-
-    /**
-     * Formats input so it can be safely used in a query
-     * PDO_OCI does not implement quote() method
-     *
-     * @param mixed  $input Value to quote
-     * @param string $type  Type of data (integer, bool, ident)
-     *
-     * @return string Quoted/converted string for use in query
-     */
-    public function quote($input, $type = null)
-    {
-        // handle int directly for better performance
-        if ($type == 'integer' || $type == 'int') {
-            return intval($input);
-        }
-
-        if (is_null($input)) {
-            return 'NULL';
-        }
-
-        if ($type == 'ident') {
-            return $this->quote_identifier($input);
-        }
-
-        switch ($type) {
-        case 'bool':
-        case 'integer':
-            return intval($input);
-        default:
-            return "'" . strtr($input, array(
-                    '?' => '??',
-                    "'" => "''",
-                    rcube_db::DEFAULT_QUOTE => rcube_db::DEFAULT_QUOTE . rcube_db::DEFAULT_QUOTE
-            )) . "'";
-        }
-    }
-
-    /**
-     * Return correct name for a specific database sequence
-     *
-     * @param string $table Table name
-     *
-     * @return string Translated sequence name
-     */
-    protected function sequence_name($table)
-    {
-        // Note: we support only one sequence per table
-        // Note: The sequence name must be <table_name>_seq
-        $sequence = $table . '_seq';
-
-        // modify sequence name if prefix is configured
-        if ($prefix = $this->options['table_prefix']) {
-            return $prefix . $sequence;
-        }
-
-        return $sequence;
-    }
-
-    /**
-     * Return SQL statement for case insensitive LIKE
-     *
-     * @param string $column Field name
-     * @param string $value  Search value
-     *
-     * @return string SQL statement to use in query
-     */
-    public function ilike($column, $value)
-    {
-        return 'UPPER(' . $this->quote_identifier($column) . ') LIKE UPPER(' . $this->quote($value) . ')';
-    }
-
-    /**
-     * Return SQL function for current time and date
-     *
-     * @param int $interval Optional interval (in seconds) to add/subtract
-     *
-     * @return string SQL function to use in query
-     */
-    public function now($interval = 0)
-    {
-        if ($interval) {
-            $interval = intval($interval);
-            return "current_timestamp + INTERVAL '$interval' SECOND";
-        }
-
-        return "current_timestamp";
-    }
-
-    /**
-     * Return SQL statement to convert a field value into a unix timestamp
-     *
-     * @param string $field Field name
-     *
-     * @return string SQL statement to use in query
-     * @deprecated
-     */
-    public function unixtimestamp($field)
-    {
-        return "(($field - to_date('1970-01-01','YYYY-MM-DD')) * 60 * 60 * 24)";
-    }
-
-    /**
-     * Adds TOP (LIMIT,OFFSET) clause to the query
-     *
-     * @param string $query  SQL query
-     * @param int    $limit  Number of rows
-     * @param int    $offset Offset
-     *
-     * @return string SQL query
-     */
-    protected function set_limit($query, $limit = 0, $offset = 0)
-    {
-        $limit  = intval($limit);
-        $offset = intval($offset);
-        $end    = $offset + $limit;
-
-        // @TODO: Oracle 12g has better OFFSET support
-
-        if (!$offset) {
-            $query = "SELECT * FROM ($query) a WHERE rownum <= $end";
-        }
-        else {
-            $query = "SELECT * FROM (SELECT a.*, rownum as rn FROM ($query) a WHERE rownum <= $end) b WHERE rn > $offset";
-        }
-
-        return $query;
-    }
-
-    /**
-     * Parse SQL file and fix table names according to table prefix
-     */
-    protected function fix_table_names($sql)
-    {
-        if (!$this->options['table_prefix']) {
-            return $sql;
-        }
-
-        $sql = parent::fix_table_names($sql);
-
-        // replace sequence names, and other Oracle-specific commands
-        $sql = preg_replace_callback('/((SEQUENCE ["]?)([^" \r\n]+)/',
-            array($this, 'fix_table_names_callback'),
-            $sql
-        );
-
-        $sql = preg_replace_callback(
-            '/([ \r\n]+["]?)([^"\' \r\n\.]+)(["]?\.nextval)/',
-            array($this, 'fix_table_names_seq_callback'),
-            $sql
-        );
-
-        return $sql;
-    }
-
-    /**
-     * Preg_replace callback for fix_table_names()
-     */
-    protected function fix_table_names_seq_callback($matches)
-    {
-        return $matches[1] . $this->options['table_prefix'] . $matches[2] . $matches[3];
-    }
-
-    /**
-     * Returns connection options from DSN array
-     */
-    protected function dsn_options($dsn)
-    {
-        $params = array();
-
-        if ($dsn['hostspec']) {
-            $host = $dsn['hostspec'];
-            if ($dsn['port']) {
-                $host .= ':' . $dsn['port'];
-            }
-
-            $params['database'] = $host . '/' . $dsn['database'];
-        }
-
-        $params['charset'] = 'UTF8';
-
-        return $params;
-    }
-
-    /**
-     * Execute the given SQL script
-     *
-     * @param string SQL queries to execute
-     *
-     * @return boolen True on success, False on error
-     */
-    public function exec_script($sql)
-    {
-        $sql  = $this->fix_table_names($sql);
-        $buff = '';
-        $body = false;
-
-        foreach (explode("\n", $sql) as $line) {
-            $tok = strtolower(trim($line));
-            if (preg_match('/^--/', $line) || $tok == '') {
-                continue;
-            }
-
-            $buff .= $line . "\n";
-
-            // detect PL/SQL function bodies, don't break on semicolon
-            if ($body && $tok == 'end;') {
-                $body = false;
-            }
-            else if (!$body && $tok == 'begin') {
-                $body = true;
-            }
-
-            if (!$body && substr($tok, -1) == ';') {
-                $this->query($buff);
-                $buff = '';
-                if ($this->db_error) {
-                    break;
-                }
-            }
-        }
-
-        return !$this->db_error;
-    }
-
-    /**
-     * Start transaction
-     *
-     * @return bool True on success, False on failure
-     */
-    public function startTransaction()
-    {
-        $this->db_connect('w', true);
-
-        // check connection before proceeding
-        if (!$this->is_connected()) {
-            return $this->last_result = false;
-        }
-
-        $this->debug('BEGIN TRANSACTION');
-
-        return $this->last_result = $this->in_transaction = true;
-    }
-
-    /**
-     * Commit transaction
-     *
-     * @return bool True on success, False on failure
-     */
-    public function endTransaction()
-    {
-        $this->db_connect('w', true);
-
-        // check connection before proceeding
-        if (!$this->is_connected()) {
-            return $this->last_result = false;
-        }
-
-        $this->debug('COMMIT TRANSACTION');
-
-        if ($result = @oci_commit($this->dbh)) {
-            $this->in_transaction = true;
-        }
-        else {
-            $this->handle_error('COMMIT');
-        }
-
-        return $this->last_result = $result;
-    }
-
-    /**
-     * Rollback transaction
-     *
-     * @return bool True on success, False on failure
-     */
-    public function rollbackTransaction()
-    {
-        $this->db_connect('w', true);
-
-        // check connection before proceeding
-        if (!$this->is_connected()) {
-            return $this->last_result = false;
-        }
-
-        $this->debug('ROLLBACK TRANSACTION');
-
-        if ($result = @oci_rollback($this->dbh)) {
-            $this->in_transaction = false;
-        }
-        else {
-            $this->handle_error('ROLLBACK');
-        }
-
-        return $this->last_result = $this->dbh->rollBack();
-    }
-}
diff --git a/program/lib/Roundcube/rcube_db_oracle.php b/program/lib/Roundcube/rcube_db_oracle.php
index ddd351ec3..338eb2e2a 100644
--- a/program/lib/Roundcube/rcube_db_oracle.php
+++ b/program/lib/Roundcube/rcube_db_oracle.php
@@ -10,8 +10,8 @@
  | See the README file for a full license statement.                     |
  |                                                                       |
  | PURPOSE:                                                              |
- |   Database wrapper class that implements PHP PDO functions            |
- |   for Oracle database                                                 |
+ |   Database wrapper class that implements database functions           |
+ |   for Oracle database using OCI8 extension                            |
  +-----------------------------------------------------------------------+
  | Author: Aleksander Machniak <machniak@kolabsys.com>                   |
  +-----------------------------------------------------------------------+
@@ -19,7 +19,6 @@
 
 /**
  * Database independent query interface
- * This is a wrapper for the PHP PDO
  *
  * @package    Framework
  * @subpackage Database
@@ -28,6 +27,49 @@ class rcube_db_oracle extends rcube_db
 {
     public $db_provider = 'oracle';
 
+
+    /**
+     * Create connection instance
+     */
+    protected function conn_create($dsn)
+    {
+        // Get database specific connection options
+        $dsn_options = $this->dsn_options($dsn);
+
+        $function = $this->db_pconn ? 'oci_pconnect' : 'oci_connect';
+
+        if (!function_exists($function)) {
+            $this->db_error     = true;
+            $this->db_error_msg = 'OCI8 extension not loaded. See http://php.net/manual/en/book.oci8.php';
+
+            rcube::raise_error(array('code' => 500, 'type' => 'db',
+                'line' => __LINE__, 'file' => __FILE__,
+                'message' => $this->db_error_msg), true, false);
+
+            return;
+        }
+
+        // connect
+        $dbh = @$function($dsn['username'], $dsn['password'], $dsn_options['database'], $dsn_options['charset']);
+
+        if (!$dbh) {
+            $error              = oci_error();
+            $this->db_error     = true;
+            $this->db_error_msg = $error['message'];
+
+            rcube::raise_error(array('code' => 500, 'type' => 'db',
+                'line' => __LINE__, 'file' => __FILE__,
+                'message' => $this->db_error_msg), true, false);
+
+            return;
+        }
+
+        // configure session
+        $this->conn_configure($dsn, $dbh);
+
+        return $dbh;
+    }
+
     /**
      * Driver-specific configuration of database connection
      *
@@ -36,8 +78,135 @@ class rcube_db_oracle extends rcube_db
      */
     protected function conn_configure($dsn, $dbh)
     {
-        $dbh->query("ALTER SESSION SET nls_date_format = 'YYYY-MM-DD'");
-        $dbh->query("ALTER SESSION SET nls_timestamp_format = 'YYYY-MM-DD HH24:MI:SS'");
+        $init_queries = array(
+            "ALTER SESSION SET nls_date_format = 'YYYY-MM-DD'",
+            "ALTER SESSION SET nls_timestamp_format = 'YYYY-MM-DD HH24:MI:SS'",
+        );
+
+        foreach ($init_queries as $query) {
+            $stmt = oci_parse($dbh, $query);
+            oci_execute($stmt);
+        }
+    }
+
+    /**
+     * Connection state checker
+     *
+     * @return boolean True if in connected state
+     */
+    public function is_connected()
+    {
+        return empty($this->dbh) ? false : $this->db_connected;
+    }
+
+    /**
+     * Execute a SQL query with limits
+     *
+     * @param string $query   SQL query to execute
+     * @param int    $offset  Offset for LIMIT statement
+     * @param int    $numrows Number of rows for LIMIT statement
+     * @param array  $params  Values to be inserted in query
+     *
+     * @return PDOStatement|bool Query handle or False on error
+     */
+    protected function _query($query, $offset, $numrows, $params)
+    {
+        $query = ltrim($query);
+
+        $this->db_connect($this->dsn_select($query), true);
+
+        // check connection before proceeding
+        if (!$this->is_connected()) {
+            return $this->last_result = false;
+        }
+
+        if ($numrows || $offset) {
+            $query = $this->set_limit($query, $numrows, $offset);
+        }
+
+        // replace self::DEFAULT_QUOTE with driver-specific quoting
+        $query = $this->query_parse($query);
+
+        // Because in Roundcube we mostly use queries that are
+        // executed only once, we will not use prepared queries
+        $pos  = 0;
+        $idx  = 0;
+        $args = array();
+
+        if (count($params)) {
+            while ($pos = strpos($query, '?', $pos)) {
+                if ($query[$pos+1] == '?') {  // skip escaped '?'
+                    $pos += 2;
+                }
+                else {
+                    $val = $this->quote($params[$idx++]);
+
+                    // long strings are not allowed inline, need to be parametrized
+                    if (strlen($val) > 4000) {
+                        $key = ':param' . (count($args) + 1);
+                        $args[$key] = $params[$idx-1];
+                        $val = $key;
+                    }
+
+                    unset($params[$idx-1]);
+                    $query = substr_replace($query, $val, $pos, 1);
+                    $pos += strlen($val);
+                }
+            }
+        }
+
+        // replace escaped '?' back to normal, see self::quote()
+        $query = str_replace('??', '?', $query);
+        $query = rtrim($query, " \t\n\r\0\x0B;");
+
+        // log query
+        $this->debug($query);
+
+        // destroy reference to previous result
+        $this->last_result  = null;
+        $this->db_error_msg = null;
+
+        // prepare query
+        $result = @oci_parse($this->dbh, $query);
+        $mode   = $this->in_transaction ? OCI_NO_AUTO_COMMIT : OCI_COMMIT_ON_SUCCESS;
+
+        if ($result) {
+            foreach ($args as $param => $arg) {
+                oci_bind_by_name($result, $param, $args[$param], -1, SQLT_LNG);
+            }
+        }
+
+        // execute query
+        if (!$result || !@oci_execute($result, $mode)) {
+            $result = $this->handle_error($query, $result);
+        }
+
+        return $this->last_result = $result;
+    }
+
+    /**
+     * Helper method to handle DB errors.
+     * This by default logs the error but could be overriden by a driver implementation
+     *
+     * @param string Query that triggered the error
+     * @return mixed Result to be stored and returned
+     */
+    protected function handle_error($query, $result = null)
+    {
+        $error = oci_error(is_resource($result) ? $result : $this->dbh);
+
+        // @TODO: Find error codes for key errors
+        if (empty($this->options['ignore_key_errors']) || !in_array($error['code'], array('23000', '23505'))) {
+            $this->db_error = true;
+            $this->db_error_msg = sprintf('[%s] %s', $error['code'], $error['message']);
+
+            rcube::raise_error(array('code' => 500, 'type' => 'db',
+                'line' => __LINE__, 'file' => __FILE__,
+                'message' => $this->db_error_msg . " (SQL Query: $query)"
+                ), true, false);
+        }
+
+        return false;
     }
 
     /**
@@ -54,9 +223,83 @@ class rcube_db_oracle extends rcube_db
         }
 
         $sequence = $this->quote_identifier($this->sequence_name($table));
-        $result   = $dbh->query("SELECT $sequence.currval FROM dual");
+        $result   = $this->query("SELECT $sequence.currval FROM dual");
+        $result   = $this->fetch_array($result);
+
+        return $result[0] ?: false;
+    }
+
+    /**
+     * Get number of affected rows for the last query
+     *
+     * @param mixed $result Optional query handle
+     *
+     * @return int Number of (matching) rows
+     */
+    public function affected_rows($result = null)
+    {
+        if ($result || ($result === null && ($result = $this->last_result))) {
+            return oci_num_rows($result);
+        }
+
+        return 0;
+    }
+
+    /**
+     * Get number of rows for a SQL query
+     * If no query handle is specified, the last query will be taken as reference
+     *
+     * @param mixed $result Optional query handle
+     * @return mixed   Number of rows or false on failure
+     * @deprecated This method shows very poor performance and should be avoided.
+     */
+    public function num_rows($result = null)
+    {
+        // not implemented
+        return false;
+    }
+
+    /**
+     * Get an associative array for one row
+     * If no query handle is specified, the last query will be taken as reference
+     *
+     * @param mixed $result Optional query handle
+     *
+     * @return mixed Array with col values or false on failure
+     */
+    public function fetch_assoc($result = null)
+    {
+        return $this->_fetch_row($result, OCI_ASSOC);
+    }
 
-        return $result ? $result->fetchColumn() : false;
+    /**
+     * Get an index array for one row
+     * If no query handle is specified, the last query will be taken as reference
+     *
+     * @param mixed $result Optional query handle
+     *
+     * @return mixed Array with col values or false on failure
+     */
+    public function fetch_array($result = null)
+    {
+        return $this->_fetch_row($result, OCI_NUM);
+    }
+
+    /**
+     * Get col values for a result row
+     *
+     * @param mixed $result Optional query handle
+     * @param int   $mode   Fetch mode identifier
+     *
+     * @return mixed Array with col values or false on failure
+     */
+    protected function _fetch_row($result, $mode)
+    {
+        if ($result || ($result === null && ($result = $this->last_result))) {
+            return oci_fetch_array($result, $mode + OCI_RETURN_NULLS + OCI_RETURN_LOBS);
+        }
+
+        return false;
     }
 
     /**
@@ -177,23 +420,13 @@ class rcube_db_oracle extends rcube_db
 
         // @TODO: Oracle 12g has better OFFSET support
 
-        $orderby = stristr($query, 'ORDER BY');
-        $select  = substr($query, 0, stripos($query, 'FROM'));
-        $offset += 1;
-
-        if ($orderby !== false) {
-            $query = trim(substr($query, 0, -1 * strlen($orderby)));
+        if (!$offset) {
+            $query = "SELECT * FROM ($query) a WHERE rownum <= $end";
         }
         else {
-            // it shouldn't happen, paging without sorting has not much sense
-            // @FIXME: I don't know how to build paging query without ORDER BY
-            $orderby = "ORDER BY 1";
+            $query = "SELECT * FROM (SELECT a.*, rownum as rn FROM ($query) a WHERE rownum <= $end) b WHERE rn > $offset";
         }
 
-        $query = preg_replace('/^SELECT\s/i', '', $query);
-        $query = "$select FROM (SELECT ROW_NUMBER() OVER ($orderby) AS row_number, $query)"
-            . " WHERE row_number BETWEEN $offset AND $end";
-
         return $query;
     }
 
@@ -232,12 +465,11 @@ class rcube_db_oracle extends rcube_db
     }
 
     /**
-     * Returns PDO DSN string from DSN array
+     * Returns connection options from DSN array
      */
-    protected function dsn_string($dsn)
+    protected function dsn_options($dsn)
     {
         $params = array();
-        $result = 'oci:';
 
         if ($dsn['hostspec']) {
             $host = $dsn['hostspec'];
@@ -245,19 +477,123 @@ class rcube_db_oracle extends rcube_db
                 $host .= ':' . $dsn['port'];
             }
 
-            $dsn['database'] = $host . '/' . $dsn['database'];
+            $params['database'] = $host . '/' . $dsn['database'];
         }
 
-        if ($dsn['database']) {
-            $params[] = 'dbname=' . $dsn['database'];
+        $params['charset'] = 'UTF8';
+
+        return $params;
+    }
+
+    /**
+     * Execute the given SQL script
+     *
+     * @param string SQL queries to execute
+     *
+     * @return boolen True on success, False on error
+     */
+    public function exec_script($sql)
+    {
+        $sql  = $this->fix_table_names($sql);
+        $buff = '';
+        $body = false;
+
+        foreach (explode("\n", $sql) as $line) {
+            $tok = strtolower(trim($line));
+            if (preg_match('/^--/', $line) || $tok == '') {
+                continue;
+            }
+
+            $buff .= $line . "\n";
+
+            // detect PL/SQL function bodies, don't break on semicolon
+            if ($body && $tok == 'end;') {
+                $body = false;
+            }
+            else if (!$body && $tok == 'begin') {
+                $body = true;
+            }
+
+            if (!$body && substr($tok, -1) == ';') {
+                $this->query($buff);
+                $buff = '';
+                if ($this->db_error) {
+                    break;
+                }
+            }
         }
 
-        $params['charset'] = 'UTF8';
+        return !$this->db_error;
+    }
+
+    /**
+     * Start transaction
+     *
+     * @return bool True on success, False on failure
+     */
+    public function startTransaction()
+    {
+        $this->db_connect('w', true);
+
+        // check connection before proceeding
+        if (!$this->is_connected()) {
+            return $this->last_result = false;
+        }
+
+        $this->debug('BEGIN TRANSACTION');
+
+        return $this->last_result = $this->in_transaction = true;
+    }
+
+    /**
+     * Commit transaction
+     *
+     * @return bool True on success, False on failure
+     */
+    public function endTransaction()
+    {
+        $this->db_connect('w', true);
 
-        if (!empty($params)) {
-            $result .= implode(';', $params);
+        // check connection before proceeding
+        if (!$this->is_connected()) {
+            return $this->last_result = false;
+        }
+
+        $this->debug('COMMIT TRANSACTION');
+
+        if ($result = @oci_commit($this->dbh)) {
+            $this->in_transaction = true;
+        }
+        else {
+            $this->handle_error('COMMIT');
+        }
+
+        return $this->last_result = $result;
+    }
+
+    /**
+     * Rollback transaction
+     *
+     * @return bool True on success, False on failure
+     */
+    public function rollbackTransaction()
+    {
+        $this->db_connect('w', true);
+
+        // check connection before proceeding
+        if (!$this->is_connected()) {
+            return $this->last_result = false;
+        }
+
+        $this->debug('ROLLBACK TRANSACTION');
+
+        if ($result = @oci_rollback($this->dbh)) {
+            $this->in_transaction = false;
+        }
+        else {
+            $this->handle_error('ROLLBACK');
         }
 
-        return $result;
+        return $this->last_result = $this->dbh->rollBack();
     }
 }