diff --git a/admin/index.php b/admin/index.php
index 8bcd769134afa..bdf0af2ea7617 100644
--- a/admin/index.php
+++ b/admin/index.php
@@ -94,15 +94,6 @@
         print_error('withoutversion', 'debug'); // without version, stop
     }
 
-/// Check DB prefix requirements are fulfilled
-    if (empty($CFG->prefix) && $DB->get_dbfamily() != 'mysql') {  //Enforce prefixes for everybody but mysql
-        print_error('prefixcannotbeempty', 'debug', '', array($CFG->prefix, $CFG->dbtype));
-    }
-
-    if ($DB->get_dbfamily() == 'oracle' && strlen($CFG->prefix) > 2) { //Max prefix length for Oracle is 2cc
-        print_error('prefixlimit', 'debug', '', $CFG->prefix);
-    }
-
 /// Check if the main tables have been installed yet or not.
     if (!$tables = $DB->get_tables() ) {    // No tables yet at all.
         $maintables = false;
diff --git a/install.php b/install.php
index da36874f83ed8..5c220a064e82a 100644
--- a/install.php
+++ b/install.php
@@ -59,7 +59,7 @@
     $INSTALL['dbhost']          = 'localhost';
     $INSTALL['dbuser']          = '';
     $INSTALL['dbpass']          = '';
-    $INSTALL['dbtype']          = 'mysql';
+    $INSTALL['dbtype']          = 'mysqli_adodb';
     $INSTALL['dbname']          = 'moodle';
     $INSTALL['prefix']          = 'mdl_';
 
@@ -150,7 +150,7 @@
 require_once($CFG->libdir.'/moodlelib.php');
 require_once($CFG->libdir.'/weblib.php');
 require_once($CFG->libdir.'/deprecatedlib.php');
-require_once($CFG->libdir.'/adodb/adodb.inc.php');
+require_once($CFG->libdir.'/dmllib.php');
 require_once($CFG->libdir.'/environmentlib.php');
 require_once($CFG->libdir.'/xmlize.php');
 require_once($CFG->libdir.'/componentlib.class.php');
@@ -160,10 +160,22 @@
 $INSTALL['version'] = $version;
 $INSTALL['release'] = $release;
 
-/// Have the $db object ready because we are going to use it often
-define ('ADODB_ASSOC_CASE', 0); //Use lowercase fieldnames for ADODB_FETCH_ASSOC
-$db = &ADONewConnection($INSTALL['dbtype']);
-$db->SetFetchMode(ADODB_FETCH_ASSOC);
+/// list all supported drivers - unsupported must be installed manually ;-)
+$supported = array (
+    'mysqli_adodb',
+    'mysql_adodb',
+    'postgres7_adodb',
+    'mssql_n_adodb',
+    'mssql_adodb',
+    'odbc_mssql_adodb',
+    'oci8po_adodb'
+);
+$databases = array ();
+foreach($supported as $driver) {
+    $classname = $driver.'_moodle_database';
+    require_once ("$CFG->libdir/dml/$classname.php");
+    $databases[$driver] = new $classname ();
+}
 
 /// guess the www root
 if ($INSTALL['wwwroot'] == '') {
@@ -241,31 +253,32 @@
     error_reporting(0);
 
     /// check wwwroot
-    if (ini_get('allow_url_fopen') && false) {  /// This was not reliable
+    if (ini_get('allow_url_fopen') && false) { /// This was not reliable
         if (($fh = @fopen($INSTALL['wwwrootform'].'/install.php', 'r')) === false) {
             $errormsg .= get_string('wwwrooterror', 'install').'<br />';
             $INSTALL['wwwrootform'] = $INSTALL['wwwroot'];
+            fclose($fh);
         }
     }
-    if ($fh) fclose($fh);
 
     /// check dirroot
-    if (($fh = @fopen($INSTALL['dirrootform'].'/install.php', 'r')) === false ) {
+    if (($fh = @fopen($INSTALL['dirrootform'].'/install.php', 'r')) === false) {
         $errormsg .= get_string('dirrooterror', 'install').'<br />';
         $INSTALL['dirrootform'] = $INSTALL['dirroot'];
+        fclose($fh);
     }
-    if ($fh) fclose($fh);
 
     /// check dataroot
     $CFG->dataroot = $INSTALL['dataroot'];
-    if (make_upload_directory('sessions', false) === false ) {
+    if (make_upload_directory('sessions', false) === false) {
         $errormsg .= get_string('datarooterror', 'install').'<br />';
     }
-    if ($fh) fclose($fh);
 
-    if (!empty($errormsg)) $nextstage = DIRECTORY;
+    if (!empty($errormsg)) {
+        $nextstage = DIRECTORY;
+    }
 
-    error_reporting(7);
+    error_reporting(38911);
 }
 
 
@@ -277,87 +290,36 @@
 
 if ($INSTALL['stage'] == DATABASE) {
 
-    /// different format for postgres7 by socket
-    if ($INSTALL['dbtype'] == 'postgres7' and ($INSTALL['dbhost'] == 'localhost' || $INSTALL['dbhost'] == '127.0.0.1')) {
-        $INSTALL['dbhost'] = "user='{$INSTALL['dbuser']}' password='{$INSTALL['dbpass']}' dbname='{$INSTALL['dbname']}'";
-        $INSTALL['dbuser'] = '';
-        $INSTALL['dbpass'] = '';
-        $INSTALL['dbname'] = '';
+    $DB = $databases[$INSTALL['dbtype']];
 
-        if ($INSTALL['prefix'] == '') { /// must have a prefix
-            $INSTALL['prefix'] = 'mdl_';
-        }
-    }
+    $dbfamily = $DB->get_dbfamily();
+    $errormsg = $DB->driver_installed();
 
-    if ($INSTALL['dbtype'] == 'mysql') {  /// Check MySQL extension is present
-        if (!extension_loaded('mysql')) {
-            $errormsg = get_string('mysqlextensionisnotpresentinphp', 'install');
-            $nextstage = DATABASE;
-        }
-    }
-
-    if ($INSTALL['dbtype'] == 'mysqli') {  /// Check MySQLi extension is present
-        if (!extension_loaded('mysqli')) {
-            $errormsg = get_string('mysqliextensionisnotpresentinphp', 'install');
-            $nextstage = DATABASE;
-        }
-    }
-
-    if ($INSTALL['dbtype'] == 'postgres7') {  /// Check PostgreSQL extension is present
-        if (!extension_loaded('pgsql')) {
-            $errormsg = get_string('pgsqlextensionisnotpresentinphp', 'install');
-            $nextstage = DATABASE;
-        }
-    }
-
-    if ($INSTALL['dbtype'] == 'mssql') {  /// Check MSSQL extension is present
-        if (!function_exists('mssql_connect')) {
-            $errormsg = get_string('mssqlextensionisnotpresentinphp', 'install');
-            $nextstage = DATABASE;
-        }
-    }
-
-    if ($INSTALL['dbtype'] == 'mssql_n') {  /// Check MSSQL extension is present
-        if (!function_exists('mssql_connect')) {
-            $errormsg = get_string('mssqlextensionisnotpresentinphp', 'install');
-            $nextstage = DATABASE;
-        }
-    }
-
-    if ($INSTALL['dbtype'] == 'odbc_mssql') {  /// Check ODBC extension is present
-        if (!extension_loaded('odbc')) {
-            $errormsg = get_string('odbcextensionisnotpresentinphp', 'install');
-            $nextstage = DATABASE;
-        }
-    }
-
-    if ($INSTALL['dbtype'] == 'oci8po') {  /// Check OCI extension is present
-        if (!extension_loaded('oci8')) {
-            $errormsg = get_string('ociextensionisnotpresentinphp', 'install');
-            $nextstage = DATABASE;
-        }
+    if ($errormsg === true) {
+        $errormsg = '';
+    } else {
+        $nextstage = DATABASE;
     }
 
-    if (empty($INSTALL['prefix']) && $INSTALL['dbtype'] != 'mysql' && $INSTALL['dbtype'] != 'mysqli') { // All DBs but MySQL require prefix (reserv. words)
+    if (empty($INSTALL['prefix']) and $dbfamily != 'mysql') { // All DBs but MySQL require prefix (reserv. words)
         $errormsg = get_string('dbwrongprefix', 'install');
         $nextstage = DATABASE;
     }
 
-    if ($INSTALL['dbtype'] == 'oci8po' && strlen($INSTALL['prefix']) > 2) { // Oracle max prefix = 2cc (30cc limit)
+    if ($dbfamily == 'oracle' and strlen($INSTALL['prefix']) > 2) { // Oracle max prefix = 2cc (30cc limit)
         $errormsg = get_string('dbwrongprefix', 'install');
         $nextstage = DATABASE;
     }
 
-    if ($INSTALL['dbtype'] == 'oci8po' && !empty($INSTALL['dbhost'])) { // Oracle host must be blank (tnsnames.ora has it)
+    if ($dbfamily == 'oracle' and !empty ($INSTALL['dbhost'])) { // Oracle host must be blank (tnsnames.ora has it)
         $errormsg = get_string('dbwronghostserver', 'install');
         $nextstage = DATABASE;
     }
 
     if (empty($errormsg)) {
-
         error_reporting(0);  // Hide errors
 
-        if (! $dbconnected = $db->Connect($INSTALL['dbhost'],$INSTALL['dbuser'],$INSTALL['dbpass'],$INSTALL['dbname'])) {
+        if (! $dbconnected = $DB->connect($INSTALL['dbhost'], $INSTALL['dbuser'], $INSTALL['dbpass'], $INSTALL['dbname'], false, $INSTALL['prefix'])) {
             $db->database = ''; // reset database name cached by ADODB. Trick from MDL-9609
             if ($dbconnected = $db->Connect($INSTALL['dbhost'],$INSTALL['dbuser'],$INSTALL['dbpass'])) { /// Try to connect without DB
                 switch ($INSTALL['dbtype']) {   /// Try to create a database
@@ -373,41 +335,14 @@
                 }
             }
         } else {
-        /// We have been able to connect properly, just test the database encoding now.
-        /// It must be Unicode for 1.8 installations.
-            $encoding = '';
-            switch ($INSTALL['dbtype']) {
-                case 'mysql':
-                case 'mysqli':
-                /// Get MySQL character_set_database value
-                    $rs = $db->Execute("SHOW VARIABLES LIKE 'character_set_database'");
-                    if ($rs && !$rs->EOF) {
-                        $records = $rs->GetAssoc(true);
-                        $encoding = $records['character_set_database']['Value'];
-                        if (strtoupper($encoding) != 'UTF8') {
-                        /// Try to set the encoding now!
-                            if (! $db->Metatables()) {  // We have no tables so go ahead
-                                $db->Execute("ALTER DATABASE `".$INSTALL['dbname']."` DEFAULT CHARACTER SET utf8 COLLATE utf8_unicode_ci");
-                                $rs = $db->Execute("SHOW VARIABLES LIKE 'character_set_database'");  // this works
-
-                            }
-                        }
-                        /// If conversion fails, skip, let environment testing do the job
-                    }
-                    break;
-                case 'postgres7':
-                /// Skip, let environment testing do the job
-                    break;
-                case 'oci8po':
-                /// Skip, let environment testing do the job
-                    break;
-            }
+// TODO: db encoding checks ??
         }
     }
 
-    error_reporting(7);
+    error_reporting(38911);
 
-    if (($dbconnected === false) and (empty($errormsg)) ) {
+/// Output db connection error
+    if ((empty($errormsg) and ($dbconnected === false)) ) {
         $errormsg = get_string('dbconnectionerror', 'install');
         $nextstage = DATABASE;
     }
@@ -441,9 +376,11 @@
 // Check if we can navigate from the environemt page (because it's ok)
 
 if ($INSTALL['stage'] == ENVIRONMENT) {
+    $DB = $databases[$INSTALL['dbtype']];
+
     error_reporting(0);  // Hide errors
-    $dbconnected = $db->Connect($INSTALL['dbhost'],$INSTALL['dbuser'],$INSTALL['dbpass'],$INSTALL['dbname']);
-    error_reporting(7);  // Show errors
+    $dbconnected = $DB->connect($INSTALL['dbhost'], $INSTALL['dbuser'], $INSTALL['dbpass'], $INSTALL['dbname'], false, $INSTALL['prefix']);
+    error_reporting(38911);  // Show errors
     if ($dbconnected) {
     /// Execute environment check, printing results
         if (!check_moodle_environment($INSTALL['release'], $environment_results, false)) {
@@ -500,7 +437,7 @@
         //We shouldn't reach this point
     }
 
-    error_reporting(7);  // Show errors
+    error_reporting(38911);  // Show errors
 
     if ($downloadsuccess) {
         $INSTALL['downloadlangpack']       = false;
@@ -523,28 +460,36 @@
 
 if ($nextstage == SAVE) {
 
-    $str  = '<?php  /// Moodle Configuration File '."\r\n";
+    $str = '<?php  /// Moodle Configuration File ' . "\r\n";
     $str .= "\r\n";
 
     $str .= 'unset($CFG);'."\r\n";
+    $str .= '$CFG = new stdClass();'."\r\n"; // prevent PHP5 strict warnings
     $str .= "\r\n";
 
-    $str .= '$CFG->dbtype    = \''.$INSTALL['dbtype']."';\r\n";
-    $str .= '$CFG->dbhost    = \''.addslashes($INSTALL['dbhost'])."';\r\n";
-    if (!empty($INSTALL['dbname'])) {
-        $str .= '$CFG->dbname    = \''.$INSTALL['dbname']."';\r\n";
-        // support single quotes in db user/passwords
-        $str .= '$CFG->dbuser    = \''.addsingleslashes($INSTALL['dbuser'])."';\r\n";
-        $str .= '$CFG->dbpass    = \''.addsingleslashes($INSTALL['dbpass'])."';\r\n";
+    $database = $databases[$INSTALL['dbtype']];
+    $database->connect($INSTALL['dbhost'], $INSTALL['dbuser'], $INSTALL['dbpass'], $INSTALL['dbname'], false, $INSTALL['prefix']);
+    $dbconfig = $database->export_dbconfig();
+    $dbconfig->persistent = false;
+
+    foreach ($dbconfig as $key=>$value) {
+        $key = str_pad($key, 9);
+        if (is_bool($value)) {
+            if ($value) {
+                $str .= '$CFG->'.$key.' = true;'."\r\n";
+            } else {
+                $str .= '$CFG->'.$key.' = false;'."\r\n";
+            }
+        } else {
+            $str .= '$CFG->'.$key.' = \''.addsingleslashes($value)."';\r\n";
+        }
     }
-    $str .= '$CFG->dbpersist =  false;'."\r\n";
-    $str .= '$CFG->prefix    = \''.$INSTALL['prefix']."';\r\n";
     $str .= "\r\n";
 
-    $str .= '$CFG->wwwroot   = \''.s($INSTALL['wwwrootform'],true)."';\r\n";
-    $str .= '$CFG->dirroot   = \''.s($INSTALL['dirrootform'],true)."';\r\n";
-    $str .= '$CFG->dataroot  = \''.s($INSTALL['dataroot'],true)."';\r\n";
-    $str .= '$CFG->admin     = \''.s($INSTALL['admindirname'],true)."';\r\n";
+    $str .= '$CFG->wwwroot   = \''.addsingleslashes($INSTALL['wwwrootform'])."';\r\n";
+    $str .= '$CFG->dirroot   = \''.addsingleslashes($INSTALL['dirrootform'])."';\r\n";
+    $str .= '$CFG->dataroot  = \''.addsingleslashes($INSTALL['dataroot'])."';\r\n";
+    $str .= '$CFG->admin     = \''.addsingleslashes($INSTALL['admindirname'])."';\r\n";
     $str .= "\r\n";
 
     $str .= '$CFG->directorypermissions = 00777;  // try 02777 on a server in Safe Mode'."\r\n";
@@ -577,8 +522,8 @@
 <link rel="shortcut icon" href="theme/standard/favicon.ico" />
 <title>Moodle Install</title>
 <meta http-equiv="content-type" content="text/html; charset=UTF-8" />
-<?php css_styles() ?>
-<?php database_js() ?>
+<?php css_styles($databases) ?>
+<?php database_js($databases) ?>
 
 </head>
 
@@ -609,52 +554,12 @@
             <?php /// Exceptionaly, depending of the DB selected, we show some different text
                   /// from the standard one to show better instructions for each DB
                 if ($nextstage == DATABASE) {
-                    echo '<script type="text/javascript" defer="defer">window.onload=toggledbinfo;</script>';
-                    echo '<div id="mysql">' . get_string('databasesettingssub_mysql', 'install');
-                    echo '<p style="text-align: center">' . get_string('databasesettingswillbecreated', 'install') . '</p>';
-                    echo '</div>';
-
-                    echo '<div id="mysqli">' . get_string('databasesettingssub_mysqli', 'install');
-                    echo '<p style="text-align: center">' . get_string('databasesettingswillbecreated', 'install') . '</p>';
-                    echo '</div>';
-
-                    echo '<div id="postgres7">' . get_string('databasesettingssub_postgres7', 'install') . '</div>';
-
-                    echo '<div id="mssql">' . get_string('databasesettingssub_mssql', 'install');
-                /// Link to mssql installation page
-                    echo "<p style='text-align:right'><a href=\"javascript:void(0)\" ";
-                    echo "onclick=\"return window.open('http://docs.moodle.org/en/Installing_MSSQL_for_PHP')\"";
-                    echo ">";
-                    echo '<img src="pix/docs.gif' . '" alt="Docs" class="iconhelp" />';
-                    echo get_string('moodledocslink', 'install') . '</a></p>';
-                    echo '</div>';
-
-                    echo '<div id="mssql_n">' . get_string('databasesettingssub_mssql_n', 'install');
-                /// Link to mssql installation page
-                    echo "<p style='text-align:right'><a href=\"javascript:void(0)\" ";
-                    echo "onclick=\"return window.open('http://docs.moodle.org/en/Installing_MSSQL_for_PHP')\"";
-                    echo ">";
-                    echo '<img src="pix/docs.gif' . '" alt="Docs" />';
-                    echo get_string('moodledocslink', 'install') . '</a></p>';
-                    echo '</div>';
-
-                    echo '<div id="odbc_mssql">'. get_string('databasesettingssub_odbc_mssql', 'install');
-                /// Link to mssql installation page
-                    echo "<p style='text-align:right'><a href=\"javascript:void(0)\" ";
-                    echo "onclick=\"return window.open('http://docs.moodle.org/en/Installing_MSSQL_for_PHP')\"";
-                    echo ">";
-                    echo '<img src="pix/docs.gif' . '" alt="Docs" class="iconhelp" />';
-                    echo get_string('moodledocslink', 'install') . '</a></p>';
-                    echo '</div>';
-
-                    echo '<div id="oci8po">' . get_string('databasesettingssub_oci8po', 'install');
-                /// Link to oracle installation page
-                    echo "<p style='text-align:right'><a href=\"javascript:void(0)\" ";
-                    echo "onclick=\"return window.open('http://docs.moodle.org/en/Installing_Oracle_for_PHP')\"";
-                    echo ">";
-                    echo '<img src="pix/docs.gif' . '" alt="Docs" class="iconhelp" />';
-                    echo get_string('moodledocslink', 'install') . '</a></p>';
-                    echo '</div>';
+                    foreach ($databases as $driver=>$database) {
+                        echo '<script type="text/javascript" defer="defer">window.onload=toggledbinfo;</script>';
+                        echo '<div id="'.$driver.'">' . $database->get_configuration_hints();
+                        echo '<p style="text-align: center">' . get_string('databasesettingswillbecreated', 'install') . '</p>';
+                        echo '</div>';
+                    }
                 } else {
                     if (!empty($substagetext[$nextstage])) {
                         echo '<p class="p_subheading">' . $substagetext[$nextstage] . '</p>';
@@ -709,13 +614,13 @@
         echo "<hr />\n";
         echo "<div style=\"text-align: ".fix_align_rtl("left")."\">\n";
         echo "<pre>\n";
-        print_r(s($str));
+        p($INSTALL['config']);
         echo "</pre>\n";
         echo "</div>\n";
     }
 } else {
     $formaction = (isset($_GET['configfile'])) ? "install.php?configfile=".$_GET['configfile'] : "install.php";
-    form_table($nextstage, $formaction);
+    form_table($nextstage, $formaction, $databases);
 }
 
 ?>
@@ -745,7 +650,7 @@
 
 //==========================================================================//
 
-function form_table($nextstage = WELCOME, $formaction = "install.php") {
+function form_table($nextstage, $formaction, $databases) {
     global $INSTALL, $db;
 
     /// Print the standard form if we aren't in the DOWNLOADLANG page
@@ -829,14 +734,19 @@ function form_table($nextstage = WELCOME, $formaction = "install.php") {
             <tr>
                 <td class="td_left"><p class="p_install"><?php print_string('dbtype', 'install') ?></p></td>
                 <td class="td_right">
-                <?php choose_from_menu (array('mysql' => get_string('mysql', 'install'),
-                                              'mysqli' => get_string('mysqli', 'install'),
-                                              'oci8po' => get_string('oci8po', 'install'),
-                                              'postgres7' => get_string('postgres7', 'install'),
-                                              'mssql' => get_string('mssql', 'install'),
-                                              'mssql_n' => get_string('mssql_n', 'install'),
-                                              'odbc_mssql' => get_string('odbc_mssql', 'install')),
-                                        'dbtype', $INSTALL['dbtype'], '', 'toggledbinfo();') ?>
+
+                <?php
+
+            $options = array ();
+            foreach ($databases as $type => $database) {
+                $name = $database->get_name();
+                if ($database->driver_installed() !== true) {
+                    $name = "$name - driver not installed"; // TODO: improve missing driver notification
+                }
+                $options[$type] = $name;
+            }
+            choose_from_menu($options, 'dbtype', $INSTALL['dbtype'], '', 'toggledbinfo();')
+?>
                 </td>
             </tr>
             <tr>
@@ -893,7 +803,7 @@ function form_table($nextstage = WELCOME, $formaction = "install.php") {
                 <?php
                     error_reporting(0);  // Hide errors
                     $dbconnected = $db->Connect($INSTALL['dbhost'],$INSTALL['dbuser'],$INSTALL['dbpass'],$INSTALL['dbname']);
-                    error_reporting(7);  // Show errors
+                    error_reporting(38911);  // Show errors
                     if ($dbconnected) {
                     /// Execute environment check, printing results
                         check_moodle_environment($INSTALL['release'], $environment_results, true);
@@ -1114,7 +1024,7 @@ function get_installer_list_of_languages() {
 
 //==========================================================================//
 
-function css_styles() {
+function css_styles($databases) {
 ?>
 
 <style type="text/css">
@@ -1194,7 +1104,7 @@ function css_styles() {
         margin-bottom: 16px;
     }
     .p_mainheader{
-        text-align: right; 
+        text-align: right;
         font-size: 20pt;
         font-weight: bold;
         margin-top: 0px;
@@ -1228,11 +1138,11 @@ function css_styles() {
         margin-bottom: 0px;
     }
     /* This override the p tag for every p tag in this installation script,
-       but not in lang\xxx\installer.php 
+       but not in lang\xxx\installer.php
       */
     .p_install {
         margin-top: 0px;
-        margin-bottom: 0px; 
+        margin-bottom: 0px;
     }
     .environmenttable {
         font-size: 10pt;
@@ -1273,7 +1183,14 @@ function css_styles() {
       padding:0px;
       margin:0px;
     }
-    #mysql, #mysqli, #postgres7, #mssql, #mssql_n, #odbc_mssql, #oci8po {
+    <?php
+        $list = array();
+        foreach ($databases as $driver=>$unused) {
+            $list[] = '#'.$driver;
+        }
+        $list = implode(',', $list);
+        echo ($list);
+    ?> {
         display: none;
     }
 
@@ -1284,7 +1201,7 @@ function css_styles() {
 
 //==========================================================================//
 
-function database_js() {
+function database_js($databases) {
 ?>
 
 <script type="text/javascript" defer="defer">
@@ -1296,37 +1213,34 @@ function toggledbinfo() {
     }
     if (document.getElementById) {
         //Hide all the divs
-        document.getElementById('mysql').style.display = '';
-        document.getElementById('mysqli').style.display = '';
-        document.getElementById('postgres7').style.display = '';
-        document.getElementById('mssql').style.display = '';
-        document.getElementById('mssql_n').style.display = '';
-        document.getElementById('odbc_mssql').style.display = '';
-        document.getElementById('oci8po').style.display = '';
+    <?php
+        $list = array();
+        foreach ($databases as $driver=>$unused) {
+            echo "document.getElementById('$driver').style.display = '';";
+        }
+    ?>
         //Show the selected div
         document.getElementById(showid).style.display = 'block';
     } else if (document.all) {
         //This is the way old msie versions work
         //Hide all the divs
-        document.all['mysql'].style.display = '';
-        document.all['mysqli'].style.display = '';
-        document.all['postgres7'].style.display = '';
-        document.all['mssql'].style.display = '';
-        document.all['mssql_n'].style.display = '';
-        document.all['odbc_mssql'].style.display = '';
-        document.all['oci8po'].style.display = '';
+    <?php
+        $list = array();
+        foreach ($databases as $driver=>$unused) {
+            echo "document.all['$driver'].style.display = '';";
+        }
+    ?>
         //Show the selected div
         document.all[showid].style.display = 'block';
     } else if (document.layers) {
         //This is the way nn4 works
         //Hide all the divs
-        document.layers['mysql'].style.display = '';
-        document.layers['mysqli'].style.display = '';
-        document.layers['postgres7'].style.display = '';
-        document.layers['mssql'].style.display = '';
-        document.layers['mssql_n'].style.display = '';
-        document.layers['odbc_mssql'].style.display = '';
-        document.layers['oci8po'].style.display = '';
+    <?php
+        $list = array();
+        foreach ($databases as $driver=>$unused) {
+            echo "document.layers['$driver'].style.display = '';";
+        }
+    ?>
         //Show the selected div
         document.layers[showid].style.display = 'block';
     }
diff --git a/lang/en_utf8/admin.php b/lang/en_utf8/admin.php
index 55232c0c72c52..5a64dd5a1b5d5 100644
--- a/lang/en_utf8/admin.php
+++ b/lang/en_utf8/admin.php
@@ -139,7 +139,7 @@
 $string['configintrotimezones'] = 'This page will search for new information about world timezones (including daylight savings time rules) and update your local database with this information.  These locations will be checked, in order: $a This procedure is generally very safe and can not break normal installations.  Do you wish to update your timezones now?';
 $string['configiplookup'] = 'When you click on an IP address (such as 34.12.222.93), such as in the logs, you are shown a map with a best guess of where that IP is located.  There are different plugins for this that you can choose from, each has benefits and disadvantages.';
 $string['configkeeptagnamecase'] = 'Check this if you want tag names to keep the original casing as entered by users who created them';
-$string['configlang'] = 'Choose a default language for the whole site.  Users can override this setting later.';
+$string['configlang'] = 'Choose a default language for the whole site.  Users can override this setting later. You can also set \$CFG->lang=\"yourlangcode_utf8\"; in config.php if you want localised error messages for database connection problems.';
 $string['configlangcache'] = 'Cache the language menu. Saves a lot of memory and processing power. If you enable this, the menu takes a few minutes to update after you have added or removed languages.';
 $string['configlangdir'] = 'Most languages are printed left-to-right, but some, like Arabic and Hebrew, are printed right-to-left.';
 $string['configlanglist'] = 'Leave this blank to allow users to choose from any language you have in this installation of Moodle.  However, you can shorten the language menu by entering a comma-separated list of language codes that you want.  For example:  en,es_es,fr,it';
diff --git a/lang/en_utf8/debug.php b/lang/en_utf8/debug.php
index 02c5951adf911..c2ecd9e6aebab 100644
--- a/lang/en_utf8/debug.php
+++ b/lang/en_utf8/debug.php
@@ -24,8 +24,8 @@
 $string['nomodules'] = 'No modules found!!';
 $string['phpvaroff'] = 'The PHP server variable \'$a[0]\' should be Off - $a[1]';
 $string['phpvaron'] = 'The PHP server variable \'$a[0]\' is not turned On - $a[1]';
-$string['prefixcannotbeempty'] = 'Table prefix \"$a[0]\" cannot be empty for your target DB ($a[1])';
-$string['prefixlimit'] = 'Table prefix \"$a\" maximum allowed length for Oracle DBs is 2cc.';
+$string['prefixcannotbeempty'] = 'Table prefix \"$a[0]\" cannot be empty for your target DB ($a[1])'; // obsoleted 2.0
+$string['prefixlimit'] = 'Table prefix \"$a\" maximum allowed length for Oracle DBs is 2cc.'; // obsoleted in 2.0
 $string['withoutversion'] = 'Main version.php was not readable or specified';
 $string['sessionmissing'] = '$a object missing from session';
 $string['siteisnotdefined'] = 'Site is not defined!';
diff --git a/lang/en_utf8/error.php b/lang/en_utf8/error.php
index 126d49c35d108..ee07f256455eb 100644
--- a/lang/en_utf8/error.php
+++ b/lang/en_utf8/error.php
@@ -117,6 +117,11 @@
 $string['csvinvalidcolsnum'] = 'INVALID CSV FILE; Each line must include 49 or 70 fields';
 $string['csvinvalidcols'] = '<b>INVALID CSV FILE:</b> First line must include "Header Fields" and the file must be type of <br />"Expanded Fields/Comma Separated"<br />or<br /> "Expanded Fields with CAVV Result Code/Comma Separated"';
 $string['csvweirdcolumns'] = 'Invalid CSV file format - number of columns is not constant!';
+$string['dbconnectionfailed'] = '<p>Error: Database connection failed.</p>
+<p>It is possible that the database is overloaded or otherwise not running properly.</p>
+<p>The site administrator should also check that the database details have been correctly specified in config.php</p>$a';
+$string['dbdriverproblem'] = '<p>Error: database driver problem detected</p>
+<p>The site administrator should verify server configuration</p><p>$a</p>';
 $string['dbupdatefailed'] = 'Database update failed.';
 $string['destinationcmnotexit'] = 'The destination course module does not exist';
 $string['downloadedfilecheckfailed'] = 'Downloaded file check failed.';
@@ -255,6 +260,10 @@
 $string['pathdoesnotstartslash'] = 'No valid arguments supplied, path does not start with slash!';
 $string['pleasereport'] = 'If you have time, please let us know what you were trying to do when the error occurred:';
 $string['pluginrequirementsnotmet'] = 'Plugin \"$a->pluginname\" ($a->pluginversion) could not be installed.  It requires a newer version of Moodle (currently you are using $a->currentmoodle, you need $a->requiremoodle).';
+$string['prefixcannotbeempty'] = '<p>Error: database table prefix can not be empty ($a)</p>
+<p>The site administrator must fix this problem.</p>';
+$string['prefixtoolong'] = '<p>Error: database table prefix is too long ($a->dbfamily)</p>
+<p>The site administrator must fix this problem. Maximum length for table prefixes in $a->dbfamily is $a->maxlength characters.</p>';
 $string['processingstops'] = 'Processing stops here. Remaining records ignored.';
 $string['refoundtoorigi'] = 'Refunded to original amount: $a';
 $string['refoundto'] = 'Can be refunded to $a';
diff --git a/lib/dml/adodb_moodle_database.php b/lib/dml/adodb_moodle_database.php
index 10f5f139c3d62..9bd9f03ffd432 100644
--- a/lib/dml/adodb_moodle_database.php
+++ b/lib/dml/adodb_moodle_database.php
@@ -1,6 +1,5 @@
 <?php  //$Id$
 
-require_once($CFG->libdir.'/adodb/adodb.inc.php');
 require_once($CFG->libdir.'/dml/moodle_database.php');
 require_once($CFG->libdir.'/dml/adodb_moodle_recordset.php');
 
@@ -13,11 +12,57 @@ abstract class adodb_moodle_database extends moodle_database {
     protected $db;
     protected $columns = array(); // I wish we had a shared memory cache for this :-(
 
-    public function __construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix);
+    /**
+     * Returns localised database type name
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function get_name() {
+        $dbtype = $this->get_dbtype();
+        return get_string($dbtype, 'install');
     }
 
-    public function connect() {
+    /**
+     * Returns db related part of config.php
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function export_dbconfig() {
+        $cfg = new stdClass();
+        $cfg->dbtype  = $this->get_dbtype();
+        $cfg->library = 'adodb';
+        $cfg->dbhost  = $this->dbhost;
+        $cfg->dbname  = $this->dbname;
+        $cfg->dbuser  = $this->dbuser;
+        $cfg->dbpass  = $this->dbpass;
+        $cfg->prefix  = $this->prefix;
+
+        return $cfg;
+    }
+
+    //TODO: preconfigure_dbconnection(): Decide if this should be declared as abstract because all adodb drivers will need it
+    /**
+     * Adodb preconnection routines, ususally sets up needed defines;
+     */
+    protected function preconfigure_dbconnection() {
+        // empty
+    }
+
+    public function connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, array $dboptions=null) {
+        $this->dbhost    = $dbhost;
+        $this->dbuser    = $dbuser;
+        $this->dbpass    = $dbpass;
+        $this->dbname    = $dbname;
+        $this->dbpersist = $dbpersist;
+        $this->prefix    = $prefix;
+        $this->dboptions = (array)$dboptions;
+
+        global $CFG;
+
+        $this->preconfigure_dbconnection();
+
+        require_once($CFG->libdir.'/adodb/adodb.inc.php');
+
         $this->db = ADONewConnection($this->get_dbtype());
 
         global $db; $db = $this->db; // TODO: BC only for now
@@ -39,10 +84,15 @@ public function connect() {
         return true;
     }
 
+    //TODO: configure_dbconnection(): Decide if this should be declared as abstract because all adodb drivers will need it
+    /**
+     * Adodb post connection routines, usually sets up encoding,e tc.
+     */
     protected function configure_dbconnection() {
         // empty
     }
 
+    //TODO: make all dblibraries return this info in a structured way (new server_info class or so, like database_column_info class)
     /**
      * Returns database server info array
      * @return array
@@ -185,6 +235,7 @@ public function execute($sql, array $params=null) {
         return $result;
     }
 
+    //TODO: do we want the *_raw() functions being public? I see the benefits but... won't that cause problems. To decide.
     /**
      * Insert new record into database, as fast as possible, no safety checks, lobs not supported.
      * @param string $table name
diff --git a/lib/dml/moodle_database.php b/lib/dml/moodle_database.php
index 58bab96e9b5d8..21c01043507d0 100644
--- a/lib/dml/moodle_database.php
+++ b/lib/dml/moodle_database.php
@@ -6,12 +6,7 @@
  */
 abstract class moodle_database {
 
-    /**
-     * supports :name, "?" or both types of parameters?
-     * must be set in implementing class constructor
-     */
-    protected $param_types;
-
+    // manipulates the db structure
     protected $database_manager;
 
     // db connection options
@@ -22,41 +17,38 @@ abstract class moodle_database {
     protected $dbpersist;
     protected $prefix;
 
-    // TODO: perf stuff goes here
-    // TODO: do we really need record caching??
+    /**
+     * Non-moodle external database used.
+     */
+    protected $external;
 
     /**
-     * Contructor - sets up database connection, prints error in case of problem.
-     * @param string $dbhost
-     * @param string $dbuser
-     * @param string $dbpass
-     * @param string $dbname
-     * @param string $dbpersist
-     * @param string $prefix table prefix
-     */
-    public function __construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        $this->dbhost    = $dbhost;
-        $this->dbuser    = $dbuser;
-        $this->dbpass    = $dbpass;
-        $this->dbname    = $dbname;
-        $this->dbpersist = $dbpersist;
-        $this->prefix    = $prefix;
-    }
+     * Database or driver specific options, such as sockets or TCPIP db connections
+     */
+    protected $dboptions;
+
+    // TODO: perf stuff goes here
+    // TODO: do we really need record caching??
 
     /**
-     * Returns database family type - describes SQL dialect
-     * @return string db family name (mysql, postgres, mssql, oracle, etc.)
+     * Contructor - instantiates the database, specifying if it's external (connect to other systems) or no (Moodle DB)
+     *              note this has effect to decide if prefix checks must be performed or no
+     * @param bool true means external database used
      */
-    public abstract function get_dbfamily();
+    public function __construct($external=false) {
+        $this->external  = $external;
+    }
 
     /**
-     * Returns database server info array
-     * @return array
+     * Detects if all needed PHP stuff installed.
+     * Note: can be used before connect()
+     * @return mixed true if ok, string if something
      */
-    public abstract function get_server_info();
+    public abstract function driver_installed();
 
     /**
      * Returns database table prefix
+     * Note: can be used before connect()
      * @return string database table prefix
      */
     public function get_prefix() {
@@ -64,23 +56,65 @@ public function get_prefix() {
     }
 
     /**
-     * Returns database type
+     * Returns database family type - describes SQL dialect
+     * Note: can be used before connect()
+     * @return string db family name (mysql, postgres, mssql, oracle, etc.)
+     */
+    public abstract function get_dbfamily();
+
+    /**
+     * Returns more specific database driver type
+     * Note: can be used before connect()
      * @return string db type mysql, mysqli, postgres7
      */
     protected abstract function get_dbtype();
 
     /**
-     * Returns supported query parameter types
-     * @return bitmask
+     * Returns localised database type name
+     * Note: can be used before connect()
+     * @return string
      */
-    protected abstract function allowed_param_types();
+    public abstract function get_name();
+
+    /**
+     * Returns localised database description
+     * Note: can be used before connect()
+     * @return string
+     */
+    public abstract function get_configuration_hints();
 
     /**
-     * Connect to db specified in constructor
-     * Must be called before any other methods.
+     * Returns db related part of config.php
+     * Note: can be used before connect()
+     * @return string
+     */
+    public abstract function export_dbconfig();
+
+    /**
+     * Connect to db
+     * Must be called before other methods.
+     * @param string $dbhost
+     * @param string $dbuser
+     * @param string $dbpass
+     * @param string $dbname
+     * @param bool $dbpersist
+     * @param mixed $prefix string means moodle db prefix, false used for external databases where prefix not used
+     * @param array $dboptions driver specific options
      * @return bool success
      */
-    public abstract function connect();
+    public abstract function connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, array $dboptions=null);
+
+    /**
+     * Returns database server info array
+     * @return array
+     */
+    public abstract function get_server_info();
+
+    /**
+     * Returns supported query parameter types
+     * @return bitmask
+     */
+    protected abstract function allowed_param_types();
 
     /**
      * Returns last error reported by database engine.
diff --git a/lib/dml/mssql_adodb_moodle_database.php b/lib/dml/mssql_adodb_moodle_database.php
index 8daf934a9f05c..b9055c8523d17 100644
--- a/lib/dml/mssql_adodb_moodle_database.php
+++ b/lib/dml/mssql_adodb_moodle_database.php
@@ -8,14 +8,34 @@
  * @package dmlib
  */
 class mssql_adodb_moodle_database extends adodb_moodle_database {
-    function __construct ($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, false, $prefix);
+
+    public function connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, array $dboptions=null) {
+        if ($prefix == '' and !$this->external) {
+            //Enforce prefixes for everybody but mysql
+            print_error('prefixcannotbeempty', 'error', '', $this->get_dbfamily());
+        }
+        return parent::connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, $dboptions);
     }
 
-    protected function configure_dbconnection() {
+    /**
+     * Detects if all needed PHP stuff installed.
+     * Do not connect to connect to db if this test fails.
+     * @return mixed true if ok, string if something
+     */
+    public function driver_installed() {
+        if (!function_exists('mssql_connect')) {
+            return get_string('mssqlextensionisnotpresentinphp', 'install');
+        }
+        return true;
+    }
+
+    protected function preconfigure_dbconnection() {
         if (!defined('ADODB_ASSOC_CASE')) {
             define ('ADODB_ASSOC_CASE', 2);
         }
+    }
+
+    protected function configure_dbconnection() {
         $this->db->SetFetchMode(ADODB_FETCH_ASSOC);
 
         /// No need to set charset. It must be specified in the driver conf
@@ -49,6 +69,21 @@ protected function get_dbtype() {
         return 'mssql';
     }
 
+    /**
+     * Returns localised database description
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function get_configuration_hints() {
+        $str = get_string('databasesettingssub_mssql', 'install');
+        $str .= "<p style='text-align:right'><a href=\"javascript:void(0)\" ";
+        $str .= "onclick=\"return window.open('http://docs.moodle.org/en/Installing_MSSQL_for_PHP')\"";
+        $str .= ">";
+        $str .= '<img src="pix/docs.gif' . '" alt="Docs" class="iconhelp" />';
+        $str .= get_string('moodledocslink', 'install') . '</a></p>';
+        return $str;
+    }
+
     /**
      * Returns supported query parameter types
      * @return bitmask
diff --git a/lib/dml/mssql_n_adodb_moodle_database.php b/lib/dml/mssql_n_adodb_moodle_database.php
index 17bf52e092949..e8a7d508fc9c3 100644
--- a/lib/dml/mssql_n_adodb_moodle_database.php
+++ b/lib/dml/mssql_n_adodb_moodle_database.php
@@ -9,9 +9,6 @@
  * @package dmlib
  */
 class mssql_n_adodb_moodle_database extends mssql_adodb_moodle_database {
-    function __construct ($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, false, $prefix);
-    }
 
     /**
      * Returns database type
@@ -21,4 +18,19 @@ protected function get_dbtype() {
         return 'mssql_n';
     }
 
+    /**
+     * Returns localised database description
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function get_configuration_hints() {
+        $str = get_string('databasesettingssub_mssql_n', 'install');
+        $str .= "<p style='text-align:right'><a href=\"javascript:void(0)\" ";
+        $str .= "onclick=\"return window.open('http://docs.moodle.org/en/Installing_MSSQL_for_PHP')\"";
+        $str .= ">";
+        $str .= '<img src="pix/docs.gif' . '" alt="Docs" class="iconhelp" />';
+        $str .= get_string('moodledocslink', 'install') . '</a></p>';
+        return $str;
+    }
+
 }
diff --git a/lib/dml/mysql_adodb_moodle_database.php b/lib/dml/mysql_adodb_moodle_database.php
index 4edab7f69717b..c796537b61f9e 100644
--- a/lib/dml/mysql_adodb_moodle_database.php
+++ b/lib/dml/mysql_adodb_moodle_database.php
@@ -9,8 +9,17 @@
  * @package dmlib
  */
 class mysql_adodb_moodle_database extends mysqli_adodb_moodle_database {
-    function __construct ($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix);
+
+    /**
+     * Detects if all needed PHP stuff installed.
+     * Do not try to connect to db if this test fails.
+     * @return mixed true if ok, string if something
+     */
+    public function driver_installed() {
+        if (!extension_loaded('mysql')) {
+            return get_string('mysqlextensionisnotpresentinphp', 'install');
+        }
+        return true;
     }
 
     /**
@@ -21,4 +30,13 @@ protected function get_dbtype() {
         return 'mysql';
     }
 
+    /**
+     * Returns localised database description
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function get_configuration_hints() {
+        return get_string('databasesettingssub_mysql', 'install');
+    }
+
 }
diff --git a/lib/dml/mysqli_adodb_moodle_database.php b/lib/dml/mysqli_adodb_moodle_database.php
index 72501dbf18837..85cf8f8e9d0b2 100644
--- a/lib/dml/mysqli_adodb_moodle_database.php
+++ b/lib/dml/mysqli_adodb_moodle_database.php
@@ -8,14 +8,26 @@
  * @package dmlib
  */
 class mysqli_adodb_moodle_database extends adodb_moodle_database {
-    function __construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix);
+
+    /**
+     * Detects if all needed PHP stuff installed.
+     * Do not connect to connect to db if this test fails.
+     * @return mixed true if ok, string if something
+     */
+    public function driver_installed() {
+        if (!extension_loaded('mysqli')) {
+            return get_string('mysqliextensionisnotpresentinphp', 'install');
+        }
+        return true;
     }
 
-    protected function configure_dbconnection() {
+    protected function preconfigure_dbconnection() {
         if (!defined('ADODB_ASSOC_CASE')) {
             define ('ADODB_ASSOC_CASE', 2);
         }
+    }
+
+    protected function configure_dbconnection() {
         $this->db->SetFetchMode(ADODB_FETCH_ASSOC);
         $this->db->Execute("SET NAMES 'utf8'");
         return true;
@@ -37,6 +49,15 @@ protected function get_dbtype() {
         return 'mysqli';
     }
 
+    /**
+     * Returns localised database description
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function get_configuration_hints() {
+        return get_string('databasesettingssub_mysqli', 'install');
+    }
+
     /**
      * Returns supported query parameter types
      * @return bitmask
diff --git a/lib/dml/oci8po_adodb_moodle_database.php b/lib/dml/oci8po_adodb_moodle_database.php
index 11559f817b65e..29bfe7e2b940f 100644
--- a/lib/dml/oci8po_adodb_moodle_database.php
+++ b/lib/dml/oci8po_adodb_moodle_database.php
@@ -8,12 +8,34 @@
  * Oracle database class using adodb backend
  * @package dmlib
  */
-class oci8_adodb_moodle_database extends adodb_moodle_database {
-    function __construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix);
+class oci8po_adodb_moodle_database extends adodb_moodle_database {
+
+    public function connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, array $dboptions=null) {
+        if ($prefix == '' and !$this->external) {
+            //Enforce prefixes for everybody but mysql
+            print_error('prefixcannotbeempty', 'error', '', $this->get_dbfamily());
+        }
+        if (!$this->external and strlen($prefix) > 2) {
+            //Max prefix length for Oracle is 2cc
+            $a = (object)array('dbfamily'=>'oracle', 'maxlength'=>2);
+            print_error('prefixtoolong', 'error', '', $a);
+        }
+        return parent::connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, $dboptions);
     }
 
-    protected function configure_dbconnection() {
+    /**
+     * Detects if all needed PHP stuff installed.
+     * Do not connect to connect to db if this test fails.
+     * @return mixed true if ok, string if something
+     */
+    public function driver_installed() {
+        if (!extension_loaded('oci8')) {
+            return get_string('ociextensionisnotpresentinphp', 'install');
+        }
+        return true;
+    }
+
+    protected function preconfigure_dbconnection() {
         if (!defined('ADODB_ASSOC_CASE')) {
             define ('ADODB_ASSOC_CASE', 0); /// Use lowercase fieldnames for ADODB_FETCH_ASSOC
                                             /// (only meaningful for oci8po, it's the default
@@ -25,18 +47,22 @@ protected function configure_dbconnection() {
         if (!defined('ADODB_PREFETCH_ROWS')) {
             define ('ADODB_PREFETCH_ROWS', 1000);
         }
+    }
+
+    protected function configure_dbconnection() {
         $this->db->SetFetchMode(ADODB_FETCH_ASSOC);
 
         /// No need to set charset. It must be specified by the NLS_LANG env. variable
+
+        /// Now set the decimal separator to DOT, Moodle & PHP will always send floats to
+        /// DB using DOTS. Manually introduced floats (if using other characters) must be
+        /// converted back to DOTs (like gradebook does)
+        $this->db->Execute("ALTER SESSION SET NLS_NUMERIC_CHARACTERS='.,'");
         /// Enable sybase quotes, so addslashes and stripslashes will use "'"
-            ini_set('magic_quotes_sybase', '1');
+        ini_set('magic_quotes_sybase', '1');
         /// NOTE: Not 100% useful because GPC has been addslashed with the setting off
         ///       so IT'S MANDATORY TO ENABLE THIS UNDER php.ini or .htaccess for this DB
         ///       or to turn off magic_quotes to allow Moodle to do it properly
-        /// Now set the decimal separator to DOT, Moodle & PHP will always send floats to
-        /// DB using DOTS. Manually introduced floats (if using other characters) must be
-        /// converted back to DOTs (like gradebook does)
-            $this->db->Execute("ALTER SESSION SET NLS_NUMERIC_CHARACTERS='.,'");
 
         return true;
     }
@@ -57,6 +83,21 @@ protected function get_dbtype() {
         return 'oci8po';
     }
 
+    /**
+     * Returns localised database description
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function get_configuration_hints() {
+        $str = get_string('databasesettingssub_oci8po', 'install');
+        $str .= "<p style='text-align:right'><a href=\"javascript:void(0)\" ";
+        $str .= "onclick=\"return window.open('http://docs.moodle.org/en/Installing_Oracle_for_PHP')\"";
+        $str .= ">";
+        $str .= '<img src="pix/docs.gif' . '" alt="Docs" class="iconhelp" />';
+        $str .= get_string('moodledocslink', 'install') . '</a></p>';
+        return $str;
+    }
+
     /**
      * Returns supported query parameter types
      * @return bitmask
@@ -458,6 +499,10 @@ public function insert_record($table, $dataobject, $returnid=true, $bulk=false)
         return (integer)$id;
 
     }
+
+    public function set_field_select($table, $newfield, $newvalue, $select, array $params=null) {
+        error('todo');
+    }
 }
 
 
diff --git a/lib/dml/oci8po_adodb_moodle_recordset.php b/lib/dml/oci8po_adodb_moodle_recordset.php
index 71a7064e1a94c..fff66d554cc27 100644
--- a/lib/dml/oci8po_adodb_moodle_recordset.php
+++ b/lib/dml/oci8po_adodb_moodle_recordset.php
@@ -4,7 +4,7 @@
  * Oracle moodle recordest with special hacks
  * @package dmlib
  */
-class oci8po_adodb_moodle_recordset implements adodb_moodle_recordset {
+class oci8po_adodb_moodle_recordset extends adodb_moodle_recordset {
     private $rs;
 
     public function __construct($rs) {
diff --git a/lib/dml/odbc_mssql_adodb_moodle_database.php b/lib/dml/odbc_mssql_adodb_moodle_database.php
index 2129e24d38a04..c6e9f35d58a2f 100644
--- a/lib/dml/odbc_mssql_adodb_moodle_database.php
+++ b/lib/dml/odbc_mssql_adodb_moodle_database.php
@@ -9,8 +9,17 @@
  * @package dmlib
  */
 class odbc_mssql_adodb_moodle_database extends mssql_adodb_moodle_database {
-    function __construct ($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, false, $prefix);
+
+    /**
+     * Detects if all needed PHP stuff installed.
+     * Do not connect to connect to db if this test fails.
+     * @return mixed true if ok, string if something
+     */
+    public function driver_installed() {
+        if (!extension_loaded('odbc')) {
+            return get_string('odbcextensionisnotpresentinphp', 'install');
+        }
+        return true;
     }
 
     /**
@@ -21,4 +30,19 @@ protected function get_dbtype() {
         return 'odbc_mssql';
     }
 
+    /**
+     * Returns localised database description
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function get_configuration_hints() {
+        $str = get_string('databasesettingssub_odbc_mssql', 'install');
+        $str .= "<p style='text-align:right'><a href=\"javascript:void(0)\" ";
+        $str .= "onclick=\"return window.open('http://docs.moodle.org/en/Installing_MSSQL_for_PHP')\"";
+        $str .= ">";
+        $str .= '<img src="pix/docs.gif' . '" alt="Docs" class="iconhelp" />';
+        $str .= get_string('moodledocslink', 'install') . '</a></p>';
+        return $str;
+    }
+
 }
diff --git a/lib/dml/pdo_moodle_database.php b/lib/dml/pdo_moodle_database.php
index 6051885d4b483..bcb1c4cc4c170 100644
--- a/lib/dml/pdo_moodle_database.php
+++ b/lib/dml/pdo_moodle_database.php
@@ -12,8 +12,9 @@ abstract class pdo_moodle_database extends moodle_database {
     protected $pdb;
     protected $columns = array(); // I wish we had a shared memory cache for this :-(
 
-    public function __construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix);
+    //TODO: This looks incorrect now IMO. Construct should have only external and connect get all the rest of params
+    public function __construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, array $dboptions=null, $external=false) {
+        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, $dboptions, $external);
     }
 
     public function connect() {
@@ -26,6 +27,7 @@ public function connect() {
         }
     }
 
+    ///TODO: not needed preconfigure_dbconnection() stuff for PDO drivers?
     protected function configure_dbconnection() {
     }
 
diff --git a/lib/dml/postgres7_adodb_moodle_database.php b/lib/dml/postgres7_adodb_moodle_database.php
index 99eb356aebdfa..a2f8ab36a375a 100644
--- a/lib/dml/postgres7_adodb_moodle_database.php
+++ b/lib/dml/postgres7_adodb_moodle_database.php
@@ -8,8 +8,38 @@
  * @package dmlib
  */
 class postgres7_adodb_moodle_database extends adodb_moodle_database {
-    function __construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix) {
-        parent::__construct($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix);
+
+    public function connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, array $dboptions=null) {
+        if ($prefix == '' and !$this->external) {
+            //Enforce prefixes for everybody but mysql
+            print_error('prefixcannotbeempty', 'error', '', $this->get_dbfamily());
+        }
+        return parent::connect($dbhost, $dbuser, $dbpass, $dbname, $dbpersist, $prefix, $dboptions);
+    }
+
+    /**
+     * Detects if all needed PHP stuff installed.
+     * Do not connect to connect to db if this test fails.
+     * @return mixed true if ok, string if something
+     */
+    public function driver_installed() {
+        if (!extension_loaded('pgsql')) {
+            return get_string('pgsqlextensionisnotpresentinphp', 'install');
+        }
+        return true;
+    }
+
+    protected function preconfigure_dbconnection() {
+        if (!defined('ADODB_ASSOC_CASE')) {
+            define ('ADODB_ASSOC_CASE', 2);
+        }
+    }
+
+    protected function configure_dbconnection() {
+        $this->db->SetFetchMode(ADODB_FETCH_ASSOC);
+        $this->db->Execute("SET NAMES 'utf8'");
+
+        return true;
     }
 
     /**
@@ -28,6 +58,40 @@ protected function get_dbtype() {
         return 'postgres7';
     }
 
+    /**
+     * Returns localised database description
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function get_configuration_hints() {
+        return get_string('databasesettingssub_postgres7', 'install');
+    }
+
+    /**
+     * Returns db related part of config.php
+     * Note: can be used before connect()
+     * @return string
+     */
+    public function export_dbconfig() {
+        $cfg = new stdClass();
+        $cfg->dbtype  = $this->get_dbtype();
+        $cfg->library = 'adodb';
+        if ($this->dbhost == 'localhost' or $this->dbhost == '127.0.0.1') {
+            $cfg->dbhost  = "user='{$this->dbuser}' password='{$this->dbpass}' dbname='{$this->dbname}'";
+            $cfg->dbname  = '';
+            $cfg->dbuser  = '';
+            $cfg->dbpass  = '';
+        } else {
+            $cfg->dbhost  = $this->dbhost;
+            $cfg->dbname  = $this->dbname;
+            $cfg->dbuser  = $this->dbuser;
+            $cfg->dbpass  = $this->dbpass;
+        }
+        $cfg->prefix  = $this->prefix;
+
+        return $cfg;
+    }
+
     /**
      * Returns supported query parameter types
      * @return bitmask
@@ -67,17 +131,6 @@ public function get_columns($table) {
         return $this->columns[$table];
     }
 
-    protected function configure_dbconnection() {
-        if (!defined('ADODB_ASSOC_CASE')) {
-            define ('ADODB_ASSOC_CASE', 2);
-        }
-
-        $this->db->SetFetchMode(ADODB_FETCH_ASSOC);
-        $this->db->Execute("SET NAMES 'utf8'");
-
-        return true;
-    }
-
     /**
      * This method will introspect inside DB to detect it it's a UTF-8 DB or no
      * Used from setup.php to set correctly "set names" when the installation
diff --git a/lib/dmllib.php b/lib/dmllib.php
index de0fd8f09cb05..1b09e3691d359 100644
--- a/lib/dmllib.php
+++ b/lib/dmllib.php
@@ -86,10 +86,14 @@ function setup_DB() {
         $CFG->dblibrary = 'adodb';
     }
 
+    if (!isset($CFG->dboptions)) {
+        $CFG->dboptions = array();
+    }
+
     if ($CFG->dblibrary == 'adodb') {
         $classname = $CFG->dbtype.'_adodb_moodle_database';
         require_once($CFG->libdir.'/dml/'.$classname.'.php');
-        $DB = new $classname($CFG->dbhost, $CFG->dbuser, $CFG->dbpass, $CFG->dbname, $CFG->dbpersist, $CFG->prefix);
+        $DB = new $classname();
 
     } else {
         error('Not implemented db library yet: '.$CFG->dblibrary);
@@ -97,34 +101,39 @@ function setup_DB() {
 
     $CFG->dbfamily = $DB->get_dbfamily(); // TODO: BC only for now
 
-    $prevdebug = error_reporting(E_ALL);  // do not hide errors yet
-    if (!$DB->connect()) {
-        // In the name of protocol correctness, monitoring and performance
-        // profiling, set the appropriate error headers for machine comsumption
-        if (isset($_SERVER['SERVER_PROTOCOL'])) {
-            // Avoid it with cron.php. Note that we assume it's HTTP/1.x
-            header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
-        }
-        // and then for human consumption...
-        echo '<html><body>';
-        echo '<table align="center"><tr>';
-        echo '<td style="color:#990000; text-align:center; font-size:large; border-width:1px; '.
-             '    border-color:#000000; border-style:solid; border-radius: 20px; border-collapse: collapse; '.
-             '    -moz-border-radius: 20px; padding: 15px">';
-        echo '<p>Error: Database connection failed.</p>';
-        echo '<p>It is possible that the database is overloaded or otherwise not running properly.</p>';
-        echo '<p>The site administrator should also check that the database details have been correctly specified in config.php</p>';
-        echo '</td></tr></table>';
-        echo '</body></html>';
+    $driverstatus = $DB->driver_installed();
 
+    if ($driverstatus !== true) {
+        print_error('dbdriverproblem', 'error', '', $driverstatus);
+    }
+
+    if (debugging('', DEBUG_ALL)) {
+        // catch errors
+        ob_start();
+    } else {
+        $prevdebug = error_reporting(0);
+    }
+    if (!$DB->connect($CFG->dbhost, $CFG->dbuser, $CFG->dbpass, $CFG->dbname, $CFG->dbpersist, $CFG->prefix, $CFG->dboptions)) {
+        if (debugging('', DEBUG_ALL)) {
+            if ($dberr = ob_get_contents()) {
+                $dberr = '<p><em>'.$dberr.'</em></p>';
+            }
+            ob_end_clean();
+        } else {
+            $dberr = '';
+        }
         if (empty($CFG->noemailever) and !empty($CFG->emailconnectionerrorsto)) {
-            mail($CFG->emailconnectionerrorsto,
-                 'WARNING: Database connection error: '.$CFG->wwwroot,
-                 'Connection error: '.$CFG->wwwroot);
+            @mail($CFG->emailconnectionerrorsto,
+                  'WARNING: Database connection error: '.$CFG->wwwroot,
+                  'Connection error: '.$CFG->wwwroot);
         }
-        die;
+        print_error('dbconnectionfailed', 'error', '', $dberr);
+    }
+    if (debugging('', DEBUG__ALL)) {
+        ob_end_clean();
+    } else {
+        error_reporting($prevdebug);
     }
-    error_reporting($prevdebug);
 
     return true;
 }
diff --git a/lib/moodlelib.php b/lib/moodlelib.php
index d7198096b9d80..f049feb359c49 100644
--- a/lib/moodlelib.php
+++ b/lib/moodlelib.php
@@ -4993,8 +4993,11 @@ function current_language() {
     } else if (!empty($USER->lang)) {
         $return = $USER->lang;
 
-    } else {
+    } else if (isset($CFG->lang)) {
         $return = $CFG->lang;
+
+    } else {
+        $return = 'en_utf8';
     }
 
     if ($return == 'en') {
diff --git a/lib/setup.php b/lib/setup.php
index cb21375440df2..782b5f2091e0f 100644
--- a/lib/setup.php
+++ b/lib/setup.php
@@ -237,14 +237,7 @@
 
 /// detect unsupported upgrade jump as soon as possible - do not change anything, do not use system functions
     if (!empty($CFG->version) and $CFG->version < 2007101509) {
-        echo '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
-<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en">
-<head>
-<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
-<title>'.get_string('error').'</title>
-</head><body>
-<div style="text-align: center; margin-top:5em;background-color:orange;">'.get_string('upgraderequires19', 'error').'</div>
-</body></html>';
+        print_error('upgraderequires19', 'error');
         die;
     }
 
diff --git a/lib/weblib.php b/lib/weblib.php
index a5cc2d7b6e19c..a87df9058d9b9 100644
--- a/lib/weblib.php
+++ b/lib/weblib.php
@@ -5623,6 +5623,7 @@ function print_scale_menu_helpbutton($courseid, $scale, $return=false) {
  * @param string $errorcode The name of the string from error.php to print
  * @param string $link The url where the user will be prompted to continue. If no url is provided the user will be directed to the site index page.
  * @param object $a Extra words and phrases that might be required in the error string
+ * @return terminates script, does not return!
  */
 function print_error ($errorcode, $module='', $link='', $a=NULL) {
 
@@ -5635,6 +5636,13 @@ function print_error ($errorcode, $module='', $link='', $a=NULL) {
         $modulelink = $module;
     }
 
+    $message = get_string($errorcode, $module, $a);
+
+    if (!isset($CFG->theme)) {
+        // error found before setup.php finished
+        print_early_error($message);
+    }
+
     if (empty($link) and !defined('ADMIN_EXT_HEADER_PRINTED')) {
         if ( !empty($SESSION->fromurl) ) {
             $link = $SESSION->fromurl;
@@ -5652,8 +5660,6 @@ function print_error ($errorcode, $module='', $link='', $a=NULL) {
         $errordocroot = 'http://docs.moodle.org';
     }
 
-    $message = get_string($errorcode, $module, $a);
-
     if (defined('FULLME') && FULLME == 'cron') {
         // Errors in cron should be mtrace'd.
         mtrace($message);
@@ -5696,6 +5702,45 @@ function print_error ($errorcode, $module='', $link='', $a=NULL) {
     die;
 }
 
+/**
+ * Internal function - do not use directly
+ * This function is used if fatal error occures before the themes are fully initialised (eg. in lib/setup.php)
+ * @param string $errorcode The name of the string from error.php to print
+ * @param string $link The url where the user will be prompted to continue. If no url is provided the user will be directed to the site index page.
+ * @param object $a Extra words and phrases that might be required in the error string
+ * @return terminates script, does not return!
+ */
+function print_early_error($message) {
+    // In the name of protocol correctness, monitoring and performance
+    // profiling, set the appropriate error headers for machine comsumption
+    if (isset($_SERVER['SERVER_PROTOCOL'])) {
+        // Avoid it with cron.php. Note that we assume it's HTTP/1.x
+        @header($_SERVER['SERVER_PROTOCOL'] . ' 503 Service Unavailable');
+    }
+
+    // better disable any caching
+    @header('Content-Type: text/html; charset=utf-8');
+    @header('Cache-Control: no-store, no-cache, must-revalidate');
+    @header('Cache-Control: post-check=0, pre-check=0', false);
+    @header('Pragma: no-cache');
+    @header('Expires: Mon, 20 Aug 1969 09:23:00 GMT');
+    @header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
+
+    echo '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" '.get_html_lang().'>
+<head>
+<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+<title>'.get_string('error').'</title>
+</head><body>
+<div style="margin-top: 6em; margin-left:auto; margin-right:auto; color:#990000; text-align:center; font-size:large; border-width:1px;
+    border-color:black; background-color:#ffffee; border-style:solid; border-radius: 20px; border-collapse: collapse;
+    width: 80%; -moz-border-radius: 20px; padding: 15px">
+'.clean_text($message, FORMAT_HTML).'
+</div>
+</body></html>';
+    die;
+}
+
 /**
  * Print an error to STDOUT and exit with a non-zero code. For commandline scripts.
  * Default errorcode is 1.