diff --git a/core/ajax/vcategories/add.php b/core/ajax/vcategories/add.php
index 8d31275dbfb5bb7f7f4f93f7e7b29c20a19f50b0..23d00af70ab8c185ae44ab4780b9bdebf5d5dff3 100644
--- a/core/ajax/vcategories/add.php
+++ b/core/ajax/vcategories/add.php
@@ -14,23 +14,25 @@ function debug($msg) {
 	OC_Log::write('core', 'ajax/vcategories/add.php: '.$msg, OC_Log::DEBUG);
 }
 
-OC_JSON::checkLoggedIn();
-$category = isset($_GET['category'])?strip_tags($_GET['category']):null;
-$app = isset($_GET['app'])?$_GET['app']:null;
+OCP\JSON::checkLoggedIn();
+OCP\JSON::callCheck();
 
-if(is_null($app)) {
-	bailOut(OC_Contacts_App::$l10n->t('Application name not provided.'));
-}
+$l = OC_L10N::get('core');
+
+$category = isset($_POST['category']) ? strip_tags($_POST['category']) : null;
+$type = isset($_POST['type']) ? $_POST['type'] : null;
 
-OC_JSON::checkAppEnabled($app);
+if(is_null($type)) {
+	bailOut($l->t('Category type not provided.'));
+}
 
 if(is_null($category)) {
-	bailOut(OC_Contacts_App::$l10n->t('No category to add?'));
+	bailOut($l->t('No category to add?'));
 }
 
 debug(print_r($category, true));
 
-$categories = new OC_VCategories($app);
+$categories = new OC_VCategories($type);
 if($categories->hasCategory($category)) {
 	bailOut(OC_Contacts_App::$l10n->t('This category already exists: '.$category));
 } else {
diff --git a/core/ajax/vcategories/addToFavorites.php b/core/ajax/vcategories/addToFavorites.php
new file mode 100644
index 0000000000000000000000000000000000000000..52f62d5fc6b0ce0e05846ece12bd9c589921c7b8
--- /dev/null
+++ b/core/ajax/vcategories/addToFavorites.php
@@ -0,0 +1,38 @@
+<?php
+/**
+ * Copyright (c) 2012 Thomas Tanghus <thomas@tanghus.net>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+function bailOut($msg) {
+	OC_JSON::error(array('data' => array('message' => $msg)));
+	OC_Log::write('core', 'ajax/vcategories/addToFavorites.php: '.$msg, OC_Log::DEBUG);
+	exit();
+}
+function debug($msg) {
+	OC_Log::write('core', 'ajax/vcategories/addToFavorites.php: '.$msg, OC_Log::DEBUG);
+}
+
+OCP\JSON::checkLoggedIn();
+OCP\JSON::callCheck();
+
+$l = OC_L10N::get('core');
+
+$id = isset($_POST['id']) ? strip_tags($_POST['id']) : null;
+$type = isset($_POST['type']) ? $_POST['type'] : null;
+
+if(is_null($type)) {
+	bailOut($l->t('Object type not provided.'));
+}
+
+if(is_null($id)) {
+	bailOut($l->t('%s ID not provided.', $type));
+}
+
+$categories = new OC_VCategories($type);
+if(!$categories->addToFavorites($id, $type)) {
+	bailOut($l->t('Error adding %s to favorites.', $id));
+}
+
+OC_JSON::success();
diff --git a/core/ajax/vcategories/delete.php b/core/ajax/vcategories/delete.php
index 74b0220870c47f856af56acd6eecd3c32b62070e..dfec378574313f71ffc073d8ae34ac941c637afb 100644
--- a/core/ajax/vcategories/delete.php
+++ b/core/ajax/vcategories/delete.php
@@ -15,21 +15,26 @@ function debug($msg) {
 	OC_Log::write('core', 'ajax/vcategories/delete.php: '.$msg, OC_Log::DEBUG);
 }
 
-OC_JSON::checkLoggedIn();
-$app = isset($_POST['app'])?$_POST['app']:null;
-$categories = isset($_POST['categories'])?$_POST['categories']:null;
-if(is_null($app)) {
-	bailOut(OC_Contacts_App::$l10n->t('Application name not provided.'));
-}
+OCP\JSON::checkLoggedIn();
+OCP\JSON::callCheck();
+
+$l = OC_L10N::get('core');
 
-OC_JSON::checkAppEnabled($app);
+$type = isset($_POST['type']) ? $_POST['type'] : null;
+$categories = isset($_POST['categories']) ? $_POST['categories'] : null;
+
+if(is_null($type)) {
+	bailOut($l->t('Object type not provided.'));
+}
 
-debug('The application "'.$app.'" uses the default file. OC_VObjects will not be updated.');
+debug('The application using category type "'
+	. $type
+	. '" uses the default file for deletion. OC_VObjects will not be updated.');
 
 if(is_null($categories)) {
-	bailOut('No categories selected for deletion.');
+	bailOut($l->t('No categories selected for deletion.'));
 }
 
-$vcategories = new OC_VCategories($app);
+$vcategories = new OC_VCategories($type);
 $vcategories->delete($categories);
 OC_JSON::success(array('data' => array('categories'=>$vcategories->categories())));
diff --git a/core/ajax/vcategories/edit.php b/core/ajax/vcategories/edit.php
index caeebcaa940f2a529d69ec58a6edaa3d48105aa0..0387b17576c4353a92c0a842e9d3040b80c09a7c 100644
--- a/core/ajax/vcategories/edit.php
+++ b/core/ajax/vcategories/edit.php
@@ -16,16 +16,18 @@ function debug($msg) {
 }
 
 OC_JSON::checkLoggedIn();
-$app = isset($_GET['app'])?$_GET['app']:null;
 
-if(is_null($app)) {
-	bailOut('Application name not provided.');
+$l = OC_L10N::get('core');
+
+$type = isset($_GET['type']) ? $_GET['type'] : null;
+
+if(is_null($type)) {
+	bailOut($l->t('Category type not provided.'));
 }
 
-OC_JSON::checkAppEnabled($app);
-$tmpl = new OC_TEMPLATE("core", "edit_categories_dialog");
+$tmpl = new OCP\Template("core", "edit_categories_dialog");
 
-$vcategories = new OC_VCategories($app);
+$vcategories = new OC_VCategories($type);
 $categories = $vcategories->categories();
 debug(print_r($categories, true));
 $tmpl->assign('categories', $categories);
diff --git a/core/ajax/vcategories/favorites.php b/core/ajax/vcategories/favorites.php
new file mode 100644
index 0000000000000000000000000000000000000000..20accea61cdbabe0d37c42ad9b12f0ae9a11bc48
--- /dev/null
+++ b/core/ajax/vcategories/favorites.php
@@ -0,0 +1,30 @@
+<?php
+/**
+ * Copyright (c) 2012 Thomas Tanghus <thomas@tanghus.net>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+function bailOut($msg) {
+	OC_JSON::error(array('data' => array('message' => $msg)));
+	OC_Log::write('core', 'ajax/vcategories/addToFavorites.php: '.$msg, OC_Log::DEBUG);
+	exit();
+}
+function debug($msg) {
+	OC_Log::write('core', 'ajax/vcategories/addToFavorites.php: '.$msg, OC_Log::DEBUG);
+}
+
+OCP\JSON::checkLoggedIn();
+OCP\JSON::callCheck();
+
+$type = isset($_GET['type']) ? $_GET['type'] : null;
+
+if(is_null($type)) {
+	$l = OC_L10N::get('core');
+	bailOut($l->t('Object type not provided.'));
+}
+
+$categories = new OC_VCategories($type);
+$ids = $categories->getFavorites($type)) {
+
+OC_JSON::success(array('ids' => $ids));
diff --git a/core/ajax/vcategories/removeFromFavorites.php b/core/ajax/vcategories/removeFromFavorites.php
new file mode 100644
index 0000000000000000000000000000000000000000..ba6e95c249735d3aeed236c6a7cfb2340b5164e6
--- /dev/null
+++ b/core/ajax/vcategories/removeFromFavorites.php
@@ -0,0 +1,38 @@
+<?php
+/**
+ * Copyright (c) 2012 Thomas Tanghus <thomas@tanghus.net>
+ * This file is licensed under the Affero General Public License version 3 or
+ * later.
+ * See the COPYING-README file.
+ */
+function bailOut($msg) {
+	OC_JSON::error(array('data' => array('message' => $msg)));
+	OC_Log::write('core', 'ajax/vcategories/removeFromFavorites.php: '.$msg, OC_Log::DEBUG);
+	exit();
+}
+function debug($msg) {
+	OC_Log::write('core', 'ajax/vcategories/removeFromFavorites.php: '.$msg, OC_Log::DEBUG);
+}
+
+OCP\JSON::checkLoggedIn();
+OCP\JSON::callCheck();
+
+$l = OC_L10N::get('core');
+
+$id = isset($_POST['id']) ? strip_tags($_POST['id']) : null;
+$type = isset($_POST['type']) ? $_POST['type'] : null;
+
+if(is_null($type)) {
+	bailOut($l->t('Object type not provided.'));
+}
+
+if(is_null($id)) {
+	bailOut($l->t('%s ID not provided.', $type));
+}
+
+$categories = new OC_VCategories($type);
+if(!$categories->removeFromFavorites($id, $type)) {
+	bailOut($l->t('Error removing %s from favorites.', $id));
+}
+
+OC_JSON::success();
diff --git a/core/js/oc-vcategories.js b/core/js/oc-vcategories.js
index c99dd51f53a6fc30f7f1bac68ab85d64aa3a41ff..609703f2cc907d7af515f1e33cdb75a83effbfd5 100644
--- a/core/js/oc-vcategories.js
+++ b/core/js/oc-vcategories.js
@@ -1,30 +1,48 @@
-var OCCategories={
-	edit:function(){
-		if(OCCategories.app == undefined) {
-			OC.dialogs.alert('OCCategories.app is not set!');
-			return;
+var OCCategories= {
+	category_favorites:'_$!<Favorite>!$_',
+	edit:function(type, cb) {
+		if(!type && !this.type) {
+			throw { name: 'MissingParameter', message: t('core', 'The object type is not specified.') };
 		}
+		type = type ? type : this.type;
 		$('body').append('<div id="category_dialog"></div>');
-		$('#category_dialog').load(OC.filePath('core', 'ajax', 'vcategories/edit.php')+'?app='+OCCategories.app, function(response){
+		$('#category_dialog').load(
+			OC.filePath('core', 'ajax', 'vcategories/edit.php') + '?type=' + type, function(response) {
 			try {
 				var jsondata = jQuery.parseJSON(response);
-				if(response.status == 'error'){
+				if(response.status == 'error') {
 					OC.dialogs.alert(response.data.message, 'Error');
 					return;
 				}
 			} catch(e) {
-				$('#edit_categories_dialog').dialog({
+				var setEnabled = function(d, enable) {
+					if(enable) {
+						d.css('cursor', 'default').find('input,button:not(#category_addbutton)')
+							.prop('disabled', false).css('cursor', 'default');
+					} else {
+						d.css('cursor', 'wait').find('input,button:not(#category_addbutton)')
+							.prop('disabled', true).css('cursor', 'wait');
+					}
+				}
+				var dlg = $('#edit_categories_dialog').dialog({
 						modal: true,
 						height: 350, minHeight:200, width: 250, minWidth: 200,
 						buttons: {
-							'Close': function() { 
-								$(this).dialog("close"); 
+							'Close': function() {
+								$(this).dialog('close');
 							},
 							'Delete':function() {
-								OCCategories.doDelete();
+								var categories = $('#categorylist').find('input:checkbox').serialize();
+								setEnabled(dlg, false);
+								OCCategories.doDelete(categories, function() {
+									setEnabled(dlg, true);
+								});
 							},
 							'Rescan':function() {
-								OCCategories.rescan();
+								setEnabled(dlg, false);
+								OCCategories.rescan(function() {
+									setEnabled(dlg, true);
+								});
 							}
 						},
 						close : function(event, ui) {
@@ -32,7 +50,7 @@ var OCCategories={
 							$('#category_dialog').remove();
 						},
 						open : function(event, ui) {
-							$('#category_addinput').live('input',function(){
+							$('#category_addinput').live('input',function() {
 								if($(this).val().length > 0) {
 									$('#category_addbutton').removeAttr('disabled');
 								}
@@ -43,7 +61,7 @@ var OCCategories={
 								$('#category_addbutton').attr('disabled', 'disabled');
 								return false;
 							});
-							$('#category_addbutton').live('click',function(e){
+							$('#category_addbutton').live('click',function(e) {
 								e.preventDefault();
 								if($('#category_addinput').val().length > 0) {
 									OCCategories.add($('#category_addinput').val());
@@ -55,58 +73,142 @@ var OCCategories={
 			}
 		});
 	},
-	_processDeleteResult:function(jsondata, status, xhr){
-		if(jsondata.status == 'success'){
+	_processDeleteResult:function(jsondata) {
+		if(jsondata.status == 'success') {
 			OCCategories._update(jsondata.data.categories);
 		} else {
 			OC.dialogs.alert(jsondata.data.message, 'Error');
 		}
 	},
-	doDelete:function(){
-		var categories = $('#categorylist').find('input:checkbox').serialize();
+	favorites:function(type, cb) {
+		if(!type && !this.type) {
+			throw { name: 'MissingParameter', message: t('core', 'The object type is not specified.') };
+		}
+		type = type ? type : this.type;
+		$.getJSON(OC.filePath('core', 'ajax', 'categories/favorites.php'), {type: type},function(jsondata) {
+			if(typeof cb == 'function') {
+				cb(jsondata);
+			} else {
+				if(jsondata.status === 'success') {
+					OCCategories._update(jsondata.data.categories);
+				} else {
+					OC.dialogs.alert(jsondata.data.message, t('core', 'Error'));
+				}
+			}
+		});
+	},
+	addToFavorites:function(id, type, cb) {
+		if(!type && !this.type) {
+			throw { name: 'MissingParameter', message: t('core', 'The object type is not specified.') };
+		}
+		type = type ? type : this.type;
+		$.post(OC.filePath('core', 'ajax', 'vcategories/addToFavorites.php'), {id:id, type:type}, function(jsondata) {
+			if(typeof cb == 'function') {
+				cb(jsondata);
+			} else {
+				if(jsondata.status !== 'success') {
+					OC.dialogs.alert(jsondata.data.message, 'Error');
+				}
+			}
+		});
+	},
+	removeFromFavorites:function(id, type, cb) {
+		if(!type && !this.type) {
+			throw { name: 'MissingParameter', message: t('core', 'The object type is not specified.') };
+		}
+		type = type ? type : this.type;
+		$.post(OC.filePath('core', 'ajax', 'vcategories/removeFromFavorites.php'), {id:id, type:type}, function(jsondata) {
+			if(typeof cb == 'function') {
+				cb(jsondata);
+			} else {
+				if(jsondata.status !== 'success') {
+					OC.dialogs.alert(jsondata.data.message, t('core', 'Error'));
+				}
+			}
+		});
+	},
+	doDelete:function(categories, type, cb) {
+		if(!type && !this.type) {
+			throw { name: 'MissingParameter', message: t('core', 'The object type is not specified.') };
+		}
+		type = type ? type : this.type;
 		if(categories == '' || categories == undefined) {
 			OC.dialogs.alert(t('core', 'No categories selected for deletion.'), t('core', 'Error'));
 			return false;
 		}
-		categories += '&app=' + OCCategories.app;
-		$.post(OC.filePath(OCCategories.app, 'ajax', 'categories/delete.php'), categories, OCCategories._processDeleteResult)
-		.error(function(xhr){
-			if (xhr.status == 404) {
-				$.post(OC.filePath('core', 'ajax', 'vcategories/delete.php'), categories, OCCategories._processDeleteResult);
-			}
-		});
+		var self = this;
+		var q = categories + '&type=' + type;
+		if(this.app) {
+			q += '&app=' + this.app;
+			$.post(OC.filePath(this.app, 'ajax', 'categories/delete.php'), q, function(jsondata) {
+				if(typeof cb == 'function') {
+					cb(jsondata);
+				} else {
+					self._processDeleteResult(jsondata);
+				}
+			});
+		} else {
+			$.post(OC.filePath('core', 'ajax', 'vcategories/delete.php'), q, function(jsondata) {
+				if(typeof cb == 'function') {
+					cb(jsondata);
+				} else {
+					self._processDeleteResult(jsondata);
+				}
+			});
+		}
 	},
-	add:function(category){
-		$.getJSON(OC.filePath('core', 'ajax', 'vcategories/add.php'),{'category':category, 'app':OCCategories.app},function(jsondata){
-			if(jsondata.status == 'success'){
-				OCCategories._update(jsondata.data.categories);
+	add:function(category, type, cb) {
+		if(!type && !this.type) {
+			throw { name: 'MissingParameter', message: t('core', 'The object type is not specified.') };
+		}
+		type = type ? type : this.type;
+		$.post(OC.filePath('core', 'ajax', 'vcategories/add.php'),{'category':category, 'type':type},function(jsondata) {
+			if(typeof cb == 'function') {
+				cb(jsondata);
 			} else {
-				OC.dialogs.alert(jsondata.data.message, 'Error');
+				if(jsondata.status === 'success') {
+					OCCategories._update(jsondata.data.categories);
+				} else {
+					OC.dialogs.alert(jsondata.data.message, 'Error');
+				}
 			}
 		});
-		return false;
 	},
-	rescan:function(){
-		$.getJSON(OC.filePath(OCCategories.app, 'ajax', 'categories/rescan.php'),function(jsondata, status, xhr){
-			if(jsondata.status == 'success'){
-				OCCategories._update(jsondata.data.categories);
+	rescan:function(app, cb) {
+		if(!app && !this.app) {
+			throw { name: 'MissingParameter', message: t('core', 'The app name is not specified.') };
+		}
+		app = app ? app : this.app;
+		$.getJSON(OC.filePath(app, 'ajax', 'categories/rescan.php'),function(jsondata, status, xhr) {
+			if(typeof cb == 'function') {
+				cb(jsondata);
 			} else {
-				OC.dialogs.alert(jsondata.data.message, 'Error');
+				if(jsondata.status === 'success') {
+					OCCategories._update(jsondata.data.categories);
+				} else {
+					OC.dialogs.alert(jsondata.data.message, 'Error');
+				}
 			}
 		}).error(function(xhr){
 			if (xhr.status == 404) {
-				OC.dialogs.alert('The required file ' + OC.filePath(OCCategories.app, 'ajax', 'categories/rescan.php') + ' is not installed!', 'Error');
+				var errormessage = t('core', 'The required file {file} is not installed!',
+					  {file: OC.filePath(app, 'ajax', 'categories/rescan.php')}, t('core', 'Error'));
+				if(typeof cb == 'function') {
+					cb({status:'error', data:{message:errormessage}});
+				} else {
+					OC.dialogs.alert(errormessage);
+				}
 			}
 		});
 	},
-	_update:function(categories){
+	_update:function(categories) {
 		var categorylist = $('#categorylist');
 		categorylist.find('li').remove();
 		for(var category in categories) {
 			var item = '<li><input type="checkbox" name="categories" value="' + categories[category] + '" />' + categories[category] + '</li>';
 			$(item).appendTo(categorylist);
 		}
-		if(OCCategories.changed != undefined) {
+		if(typeof OCCategories.changed === 'function') {
 			OCCategories.changed(categories);
 		}
 	}
diff --git a/core/routes.php b/core/routes.php
index 6f9993566890a9d95098186edb6cd39385f57e76..fc511d403d85ba24966930854b17b21c748f2157 100644
--- a/core/routes.php
+++ b/core/routes.php
@@ -24,6 +24,12 @@ $this->create('core_ajax_vcategories_add', '/core/ajax/vcategories/add.php')
 	->actionInclude('core/ajax/vcategories/add.php');
 $this->create('core_ajax_vcategories_delete', '/core/ajax/vcategories/delete.php')
 	->actionInclude('core/ajax/vcategories/delete.php');
+$this->create('core_ajax_vcategories_addtofavorites', '/core/ajax/vcategories/addToFavorites.php')
+	->actionInclude('core/ajax/vcategories/addToFavorites.php');
+$this->create('core_ajax_vcategories_removefromfavorites', '/core/ajax/vcategories/removeFromFavorites.php')
+	->actionInclude('core/ajax/vcategories/removeFromFavorites.php');
+$this->create('core_ajax_vcategories_favorites', '/core/ajax/vcategories/favorites.php')
+	->actionInclude('core/ajax/vcategories/favorites.php');
 $this->create('core_ajax_vcategories_edit', '/core/ajax/vcategories/edit.php')
 	->actionInclude('core/ajax/vcategories/edit.php');
 // Routing
diff --git a/core/templates/edit_categories_dialog.php b/core/templates/edit_categories_dialog.php
index 8997fa586bd9fc0a4ea6edd8a77652e1c75c5a10..d0b7b5ee62afe254329e5c6c962e36259f6dadd9 100644
--- a/core/templates/edit_categories_dialog.php
+++ b/core/templates/edit_categories_dialog.php
@@ -6,11 +6,14 @@ $categories = isset($_['categories'])?$_['categories']:array();
 	<form method="post" id="categoryform">
 	<div class="scrollarea">
 	<ul id="categorylist">
-	<?php foreach($categories as $category) { ?>
+	<?php foreach($categories as $category): ?>
 	<li><input type="checkbox" name="categories[]" value="<?php echo $category; ?>" /><?php echo $category; ?></li>
-	<?php } ?>
+	<?php endforeach; ?>
 	</ul>
 	</div>
-	<div class="bottombuttons"><input type="text" id="category_addinput" name="category" /><button id="category_addbutton" disabled="disabled"><?php echo $l->t('Add'); ?></button></div>
+	<div class="bottombuttons">
+		<input type="text" id="category_addinput" name="category" />
+		<button id="category_addbutton" disabled="disabled"><?php echo $l->t('Add'); ?></button>
+	</div>
 	</form>
 </div>
diff --git a/db_structure.xml b/db_structure.xml
index 99a30cb6137aab440c3290c0b4725c6707eb5329..851c8aa998dfcea2d97f6db9cdac2a50c590438d 100644
--- a/db_structure.xml
+++ b/db_structure.xml
@@ -671,4 +671,125 @@
 
 	</table>
 
+	<table>
+
+		<name>*dbprefix*vcategory</name>
+
+		<declaration>
+
+			<field>
+				<name>id</name>
+				<type>integer</type>
+				<default>0</default>
+				<notnull>true</notnull>
+				<autoincrement>1</autoincrement>
+				<unsigned>true</unsigned>
+				<length>4</length>
+			</field>
+
+			<field>
+				<name>uid</name>
+				<type>text</type>
+				<default></default>
+				<notnull>true</notnull>
+				<length>64</length>
+			</field>
+
+			<field>
+				<name>type</name>
+				<type>text</type>
+				<default></default>
+				<notnull>true</notnull>
+				<length>64</length>
+			</field>
+
+			<field>
+				<name>category</name>
+				<type>text</type>
+				<default></default>
+				<notnull>true</notnull>
+				<length>255</length>
+			</field>
+
+			<index>
+				<name>uid_index</name>
+				<field>
+					<name>uid</name>
+					<sorting>ascending</sorting>
+				</field>
+			</index>
+
+			<index>
+				<name>type_index</name>
+				<field>
+					<name>type</name>
+					<sorting>ascending</sorting>
+				</field>
+			</index>
+
+			<index>
+				<name>category_index</name>
+				<field>
+					<name>category</name>
+					<sorting>ascending</sorting>
+				</field>
+			</index>
+
+		</declaration>
+	</table>
+
+	<table>
+
+		<name>*dbprefix*vcategory_to_object</name>
+
+		<declaration>
+
+		<field>
+			<name>objid</name>
+			<type>integer</type>
+			<default>0</default>
+			<notnull>true</notnull>
+			<unsigned>true</unsigned>
+			<length>4</length>
+		</field>
+
+		<field>
+			<name>categoryid</name>
+			<type>integer</type>
+			<default>0</default>
+			<notnull>true</notnull>
+			<unsigned>true</unsigned>
+			<length>4</length>
+		</field>
+
+		<field>
+			<name>type</name>
+			<type>text</type>
+			<default></default>
+			<notnull>true</notnull>
+			<length>64</length>
+		</field>
+
+		<index>
+			<primary>true</primary>
+			<unique>true</unique>
+			<name>category_object_index</name>
+			<field>
+				<name>categoryid</name>
+				<sorting>ascending</sorting>
+			</field>
+			<field>
+				<name>objid</name>
+				<sorting>ascending</sorting>
+			</field>
+			<field>
+				<name>type</name>
+				<sorting>ascending</sorting>
+			</field>
+		</index>
+
+		</declaration>
+
+	</table>
+
 </database>
diff --git a/lib/db.php b/lib/db.php
index fba2687967f1aa2cd820df0dc9b61df983a79e03..de42626563d4e84c4dd859242baec516332e0aa0 100644
--- a/lib/db.php
+++ b/lib/db.php
@@ -541,6 +541,78 @@ class OC_DB {
 		return true;
 	}
 
+	/**
+	 * @brief Insert a row if a matching row doesn't exists.
+	 * @param string $table. The table to insert into in the form '*PREFIX*tableName'
+	 * @param array $input. An array of fieldname/value pairs
+	 * @returns The return value from PDOStatementWrapper->execute()
+	 */
+	public static function insertIfNotExist($table, $input) {
+		self::connect();
+		$prefix = OC_Config::getValue( "dbtableprefix", "oc_" );
+		$table = str_replace( '*PREFIX*', $prefix, $table );
+
+		if(is_null(self::$type)) {
+			self::$type=OC_Config::getValue( "dbtype", "sqlite" );
+		}
+		$type = self::$type;
+
+		$query = '';
+		// differences in escaping of table names ('`' for mysql) and getting the current timestamp
+		if( $type == 'sqlite' || $type == 'sqlite3' ) {
+			// NOTE: For SQLite we have to use this clumsy approach
+			// otherwise all fieldnames used must have a unique key.
+			$query = 'SELECT * FROM "' . $table . '" WHERE ';
+			foreach($input as $key => $value) {
+				$query .= $key . " = '" . $value . '\' AND ';
+			}
+			$query = substr($query, 0, strlen($query) - 5);
+			try {
+				$stmt = self::prepare($query);
+				$result = $stmt->execute();
+			} catch(PDOException $e) {
+				$entry = 'DB Error: "'.$e->getMessage() . '"<br />';
+				$entry .= 'Offending command was: ' . $query . '<br />';
+				OC_Log::write('core', $entry, OC_Log::FATAL);
+				error_log('DB error: '.$entry);
+				die( $entry );
+			}
+			
+			if($result->numRows() == 0) {
+				$query = 'INSERT INTO "' . $table . '" ("'
+					. implode('","', array_keys($input)) . '") VALUES("'
+					. implode('","', array_values($input)) . '")';
+			} else {
+				return true;
+			}
+		} elseif( $type == 'pgsql' || $type == 'oci' || $type == 'mysql') {
+			$query = 'INSERT INTO `' .$table . '` ('
+				. implode(',', array_keys($input)) . ') SELECT \''
+				. implode('\',\'', array_values($input)) . '\' FROM ' . $table . ' WHERE ';
+
+			foreach($input as $key => $value) {
+				$query .= $key . " = '" . $value . '\' AND ';
+			}
+			$query = substr($query, 0, strlen($query) - 5);
+			$query .= ' HAVING COUNT(*) = 0';
+		}
+
+		// TODO: oci should be use " (quote) instead of ` (backtick).
+		//OC_Log::write('core', __METHOD__ . ', type: ' . $type . ', query: ' . $query, OC_Log::DEBUG);
+
+		try {
+			$result = self::prepare($query);
+		} catch(PDOException $e) {
+			$entry = 'DB Error: "'.$e->getMessage() . '"<br />';
+			$entry .= 'Offending command was: ' . $query.'<br />';
+			OC_Log::write('core', $entry, OC_Log::FATAL);
+			error_log('DB error: ' . $entry);
+			die( $entry );
+		}
+
+		return $result->execute();
+	}
+	
 	/**
 	 * @brief does minor changes to query
 	 * @param string $query Query string
diff --git a/lib/public/db.php b/lib/public/db.php
index d2484b6eb83032368b1382ed6a2344efcb9aee68..92ff8f93a227877bed86d428b87fe1370780a5a8 100644
--- a/lib/public/db.php
+++ b/lib/public/db.php
@@ -45,6 +45,27 @@ class DB {
 		return(\OC_DB::prepare($query, $limit, $offset));
 	}
 
+	/**
+	 * @brief Insert a row if a matching row doesn't exists.
+	 * @param $table string The table name (will replace *PREFIX*) to perform the replace on.
+	 * @param $input array
+	 * 
+	 * The input array if in the form:
+	 * 
+	 * array ( 'id' => array ( 'value' => 6,
+	 *	'key' => true
+	 *	),
+	 *	'name' => array ('value' => 'Stoyan'),
+	 *	'family' => array ('value' => 'Stefanov'),
+	 *	'birth_date' => array ('value' => '1975-06-20')
+	 *	);
+	 * @returns true/false
+	 *
+	 */
+	public static function insertIfNotExist($table, $input) {
+		return(\OC_DB::insertIfNotExist($table, $input));
+	}
+	
 	/**
 	 * @brief gets last value of autoincrement
 	 * @param $table string The optional table name (will replace *PREFIX*) and add sequence suffix
diff --git a/lib/util.php b/lib/util.php
index 73b72bad1a5370aea34cd37a6a156cf884511cc7..da57b226ba05c6b2bd1907d1bc08eb11e87221c1 100755
--- a/lib/util.php
+++ b/lib/util.php
@@ -95,7 +95,7 @@ class OC_Util {
 	 */
 	public static function getVersion() {
 		// hint: We only can count up. So the internal version number of ownCloud 4.5 will be 4.90.0. This is not visible to the user
-		return array(4, 91, 00);
+		return array(4, 91, 01);
 	}
 
 	/**
diff --git a/lib/vcategories.php b/lib/vcategories.php
index 46256def9c4e674b5a74c0dbbe1e0660d3ba7e46..406a4eb1074cd4b1ccf0c8a9eb5dac05748621ad 100644
--- a/lib/vcategories.php
+++ b/lib/vcategories.php
@@ -21,6 +21,7 @@
 *
 */
 
+OC_Hook::connect('OC_User', 'post_deleteUser', 'OC_VCategories', 'post_deleteUser');
 
 /**
  * Class for easy access to categories in VCARD, VEVENT, VTODO and VJOURNAL.
@@ -28,50 +29,261 @@
  * anything else that is either parsed from a vobject or that the user chooses
  * to add.
  * Category names are not case-sensitive, but will be saved with the case they
- * are entered in. If a user already has a category 'family' for an app, and
+ * are entered in. If a user already has a category 'family' for a type, and
  * tries to add a category named 'Family' it will be silently ignored.
- * NOTE: There is a limitation in that the the configvalue field in the
- * preferences table is a varchar(255).
  */
 class OC_VCategories {
-	const PREF_CATEGORIES_LABEL = 'extra_categories';
+
 	/**
 	 * Categories
 	 */
 	private $categories = array();
 
-	private $app = null;
+	/**
+	 * Used for storing objectid/categoryname pairs while rescanning.
+	 */
+	private static $relations = array();
+
+	private $type = null;
 	private $user = null;
 
+	const CATEGORY_TABLE = '*PREFIX*vcategory';
+	const RELATION_TABLE = '*PREFIX*vcategory_to_object';
+
+	const CATEGORY_FAVORITE = '_$!<Favorite>!$_';
+
+	const FORMAT_LIST = 0;
+	const FORMAT_MAP  = 1;
+
 	/**
 	* @brief Constructor.
-	* @param $app The application identifier e.g. 'contacts' or 'calendar'.
+	* @param $type The type identifier e.g. 'contact' or 'event'.
 	* @param $user The user whos data the object will operate on. This
 	*   parameter should normally be omitted but to make an app able to
 	*   update categories for all users it is made possible to provide it.
 	* @param $defcategories An array of default categories to be used if none is stored.
 	*/
-	public function __construct($app, $user=null, $defcategories=array()) {
-		$this->app = $app;
+	public function __construct($type, $user=null, $defcategories=array()) {
+		$this->type = $type;
 		$this->user = is_null($user) ? OC_User::getUser() : $user;
-		$categories = trim(OC_Preferences::getValue($this->user, $app, self::PREF_CATEGORIES_LABEL, ''));
-		if ($categories) {
-			$categories = @unserialize($categories);
+
+		$this->loadCategories();
+		OCP\Util::writeLog('core', __METHOD__ . ', categories: '
+			. print_r($this->categories, true),
+			OCP\Util::DEBUG
+		);
+
+		if($defcategories && count($this->categories) === 0) {
+			$this->addMulti($defcategories, true);
+		}
+	}
+
+	/**
+	* @brief Load categories from db.
+	*/
+	private function loadCategories() {
+		$this->categories = array();
+		$result = null;
+		$sql = 'SELECT `id`, `category` FROM `' . self::CATEGORY_TABLE . '` '
+			. 'WHERE `uid` = ? AND `type` = ? ORDER BY `category`';
+		try {
+			$stmt = OCP\DB::prepare($sql);
+			$result = $stmt->execute(array($this->user, $this->type));
+			if (OC_DB::isError($result)) {
+				OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+			}
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+				OCP\Util::ERROR);
+		}
+
+		if(!is_null($result)) {
+			while( $row = $result->fetchRow()) {
+				// The keys are prefixed because array_search wouldn't work otherwise :-/
+				$this->categories[$row['id']] = $row['category'];
+			}
+		}
+		OCP\Util::writeLog('core', __METHOD__.', categories: ' . print_r($this->categories, true),
+			OCP\Util::DEBUG);
+	}
+
+
+	/**
+	* @brief Check if any categories are saved for this type and user.
+	* @returns boolean.
+	* @param $type The type identifier e.g. 'contact' or 'event'.
+	* @param $user The user whos categories will be checked. If not set current user will be used.
+	*/
+	public static function isEmpty($type, $user = null) {
+		$user = is_null($user) ? OC_User::getUser() : $user;
+		$sql = 'SELECT COUNT(*) FROM `' . self::CATEGORY_TABLE . '` '
+			. 'WHERE `uid` = ? AND `type` = ?';
+		try {
+			$stmt = OCP\DB::prepare($sql);
+			$result = $stmt->execute(array($user, $type));
+			if (OC_DB::isError($result)) {
+				OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+				return false;
+			}
+			return ($result->numRows() == 0);
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+				OCP\Util::ERROR);
+			return false;
 		}
-		$this->categories = is_array($categories) ? $categories : $defcategories;
 	}
 
 	/**
 	* @brief Get the categories for a specific user.
+	* @param
 	* @returns array containing the categories as strings.
 	*/
-	public function categories() {
-		//OC_Log::write('core', 'OC_VCategories::categories: '.print_r($this->categories, true), OC_Log::DEBUG);
+	public function categories($format = null) {
 		if(!$this->categories) {
 			return array();
 		}
-		usort($this->categories, 'strnatcasecmp'); // usort to also renumber the keys
-		return $this->categories;
+		$categories = array_values($this->categories);
+		uasort($categories, 'strnatcasecmp');
+		if($format == self::FORMAT_MAP) {
+			$catmap = array();
+			foreach($categories as $category) {
+				if($category !== self::CATEGORY_FAVORITE) {
+					$catmap[] = array(
+						'id' => $this->array_searchi($category, $this->categories),
+						'name' => $category
+						);
+				}
+			}
+			return $catmap;
+		}
+
+		// Don't add favorites to normal categories.
+		$favpos = array_search(self::CATEGORY_FAVORITE, $categories);
+		if($favpos !== false) {
+			return array_splice($categories, $favpos);
+		} else {
+			return $categories;
+		}
+	}
+
+	/**
+	* Get the a list if items belonging to $category.
+	*
+	* Throws an exception if the category could not be found.
+	*
+	* @param string|integer $category Category id or name.
+	* @returns array An array of object ids or false on error.
+	*/
+	public function idsForCategory($category) {
+		$result = null;
+		if(is_numeric($category)) {
+			$catid = $category;
+		} elseif(is_string($category)) {
+			$catid = $this->array_searchi($category, $this->categories);
+		}
+		OCP\Util::writeLog('core', __METHOD__.', category: '.$catid.' '.$category, OCP\Util::DEBUG);
+		if($catid === false) {
+			$l10n = OC_L10N::get('core');
+			throw new Exception(
+				$l10n->t('Could not find category "%s"', $category)
+			);
+		}
+
+		$ids = array();
+		$sql = 'SELECT `objid` FROM `' . self::RELATION_TABLE
+			. '` WHERE `categoryid` = ?';
+
+		try {
+			$stmt = OCP\DB::prepare($sql);
+			$result = $stmt->execute(array($catid));
+			if (OC_DB::isError($result)) {
+				OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+				return false;
+			}
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+				OCP\Util::ERROR);
+			return false;
+		}
+
+		if(!is_null($result)) {
+			while( $row = $result->fetchRow()) {
+				$ids[] = (int)$row['objid'];
+			}
+		}
+
+		return $ids;
+	}
+
+	/**
+	* Get the a list if items belonging to $category.
+	*
+	* Throws an exception if the category could not be found.
+	*
+	* @param string|integer $category Category id or name.
+	* @param array $tableinfo Array in the form {'tablename' => table, 'fields' => ['field1', 'field2']}
+	* @param int $limit
+	* @param int $offset
+	*
+	* This generic method queries a table assuming that the id
+	* field is called 'id' and the table name provided is in
+	* the form '*PREFIX*table_name'.
+	*
+	* If the category name cannot be resolved an exception is thrown.
+	*
+	* TODO: Maybe add the getting permissions for objects?
+	*
+	* @returns array containing the resulting items or false on error.
+	*/
+	public function itemsForCategory($category, $tableinfo, $limit = null, $offset = null) {
+		$result = null;
+		if(is_numeric($category)) {
+			$catid = $category;
+		} elseif(is_string($category)) {
+			$catid = $this->array_searchi($category, $this->categories);
+		}
+		OCP\Util::writeLog('core', __METHOD__.', category: '.$catid.' '.$category, OCP\Util::DEBUG);
+		if($catid === false) {
+			$l10n = OC_L10N::get('core');
+			throw new Exception(
+				$l10n->t('Could not find category "%s"', $category)
+			);
+		}
+		$fields = '';
+		foreach($tableinfo['fields'] as $field) {
+			$fields .= '`' . $tableinfo['tablename'] . '`.`' . $field . '`,';
+		}
+		$fields = substr($fields, 0, -1);
+
+		$items = array();
+		$sql = 'SELECT `' . self::RELATION_TABLE . '`.`categoryid`, ' . $fields
+			. ' FROM `' . $tableinfo['tablename'] . '` JOIN `'
+			. self::RELATION_TABLE . '` ON `' . $tableinfo['tablename']
+			. '`.`id` = `' . self::RELATION_TABLE . '`.`objid` WHERE `'
+			. self::RELATION_TABLE . '`.`categoryid` = ?';
+
+		try {
+			$stmt = OCP\DB::prepare($sql, $limit, $offset);
+			$result = $stmt->execute(array($catid));
+			if (OC_DB::isError($result)) {
+				OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+				return false;
+			}
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+				OCP\Util::ERROR);
+			return false;
+		}
+
+		if(!is_null($result)) {
+			while( $row = $result->fetchRow()) {
+				$items[] = $row;
+			}
+		}
+		//OCP\Util::writeLog('core', __METHOD__.', count: ' . count($items), OCP\Util::DEBUG);
+		//OCP\Util::writeLog('core', __METHOD__.', sql: ' . $sql, OCP\Util::DEBUG);
+
+		return $items;
 	}
 
 	/**
@@ -84,22 +296,51 @@ class OC_VCategories {
 	}
 
 	/**
-	* @brief Add a new category name.
+	* @brief Add a new category.
+	* @param $name A string with a name of the category
+	* @returns int the id of the added category or false if it already exists.
+	*/
+	public function add($name) {
+		OCP\Util::writeLog('core', __METHOD__.', name: ' . $name, OCP\Util::DEBUG);
+		if($this->hasCategory($name)) {
+			OCP\Util::writeLog('core', __METHOD__.', name: ' . $name. ' exists already', OCP\Util::DEBUG);
+			return false;
+		}
+		OCP\DB::insertIfNotExist(self::CATEGORY_TABLE,
+			array(
+				'uid' => $this->user,
+				'type' => $this->type,
+				'category' => $name,
+			));
+		$id = OCP\DB::insertid(self::CATEGORY_TABLE);
+		OCP\Util::writeLog('core', __METHOD__.', id: ' . $id, OCP\Util::DEBUG);
+		$this->categories[$id] = $name;
+		return $id;
+	}
+
+	/**
+	* @brief Add a new category.
 	* @param $names A string with a name or an array of strings containing
 	* the name(s) of the categor(y|ies) to add.
 	* @param $sync bool When true, save the categories
+	* @param $id int Optional object id to add to this|these categor(y|ies)
 	* @returns bool Returns false on error.
 	*/
-	public function add($names, $sync=false) {
+	public function addMulti($names, $sync=false, $id = null) {
 		if(!is_array($names)) {
 			$names = array($names);
 		}
 		$names = array_map('trim', $names);
 		$newones = array();
 		foreach($names as $name) {
-			if(($this->in_arrayi($name, $this->categories) == false) && $name != '') {
+			if(($this->in_arrayi(
+				$name, $this->categories) == false) && $name != '') {
 				$newones[] = $name;
 			}
+			if(!is_null($id) ) {
+				// Insert $objectid, $categoryid  pairs if not exist.
+				self::$relations[] = array('objid' => $id, 'category' => $name);
+			}
 		}
 		if(count($newones) > 0) {
 			$this->categories = array_merge($this->categories, $newones);
@@ -114,8 +355,8 @@ class OC_VCategories {
 	* @brief Extracts categories from a vobject and add the ones not already present.
 	* @param $vobject The instance of OC_VObject to load the categories from.
 	*/
-	public function loadFromVObject($vobject, $sync=false) {
-		$this->add($vobject->getAsArray('CATEGORIES'), $sync);
+	public function loadFromVObject($id, $vobject, $sync=false) {
+		$this->addMulti($vobject->getAsArray('CATEGORIES'), $sync, $id);
 	}
 
 	/**
@@ -128,23 +369,62 @@ class OC_VCategories {
 	*	$result = $stmt->execute();
 	*	$objects = array();
 	*	if(!is_null($result)) {
-	*		while( $row = $result->fetchRow()) {
-	*			$objects[] = $row['carddata'];
+	*		while( $row = $result->fetchRow()){
+	*			$objects[] = array($row['id'], $row['carddata']);
 	*		}
 	*	}
 	*	$categories->rescan($objects);
 	*/
 	public function rescan($objects, $sync=true, $reset=true) {
+
 		if($reset === true) {
+			$result = null;
+			// Find all objectid/categoryid pairs.
+			try {
+				$stmt = OCP\DB::prepare('SELECT `id` FROM `' . self::CATEGORY_TABLE . '` '
+					. 'WHERE `uid` = ? AND `type` = ?');
+				$result = $stmt->execute(array($this->user, $this->type));
+				if (OC_DB::isError($result)) {
+					OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+					return false;
+				}
+			} catch(Exception $e) {
+				OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+					OCP\Util::ERROR);
+			}
+
+			// And delete them.
+			if(!is_null($result)) {
+				$stmt = OCP\DB::prepare('DELETE FROM `' . self::RELATION_TABLE . '` '
+					. 'WHERE `categoryid` = ? AND `type`= ?');
+				while( $row = $result->fetchRow()) {
+					$stmt->execute(array($row['id'], $this->type));
+				}
+			}
+			try {
+				$stmt = OCP\DB::prepare('DELETE FROM `' . self::CATEGORY_TABLE . '` '
+					. 'WHERE `uid` = ? AND `type` = ?');
+				$result = $stmt->execute(array($this->user, $this->type));
+				if (OC_DB::isError($result)) {
+					OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+					return;
+				}
+			} catch(Exception $e) {
+				OCP\Util::writeLog('core', __METHOD__ . ', exception: '
+					. $e->getMessage(), OCP\Util::ERROR);
+				return;
+			}
 			$this->categories = array();
 		}
+		// Parse all the VObjects
 		foreach($objects as $object) {
-			//OC_Log::write('core', 'OC_VCategories::rescan: '.substr($object, 0, 100).'(...)', OC_Log::DEBUG);
-			$vobject = OC_VObject::parse($object);
+			$vobject = OC_VObject::parse($object[1]);
 			if(!is_null($vobject)) {
-				$this->loadFromVObject($vobject, $sync);
+				// Load the categories
+				$this->loadFromVObject($object[0], $vobject, $sync);
 			} else {
-				OC_Log::write('core', 'OC_VCategories::rescan, unable to parse. ID: '.', '.substr($object, 0, 100).'(...)', OC_Log::DEBUG);
+				OC_Log::write('core', __METHOD__ . ', unable to parse. ID: ' . ', '
+					. substr($object, 0, 100) . '(...)', OC_Log::DEBUG);
 			}
 		}
 		$this->save();
@@ -155,15 +435,223 @@ class OC_VCategories {
 	 */
 	private function save() {
 		if(is_array($this->categories)) {
-			usort($this->categories, 'strnatcasecmp'); // usort to also renumber the keys
-			$escaped_categories = serialize($this->categories);
-			OC_Preferences::setValue($this->user, $this->app, self::PREF_CATEGORIES_LABEL, $escaped_categories);
-			OC_Log::write('core', 'OC_VCategories::save: '.print_r($this->categories, true), OC_Log::DEBUG);
+			foreach($this->categories as $category) {
+				OCP\DB::insertIfNotExist(self::CATEGORY_TABLE,
+					array(
+						'uid' => $this->user,
+						'type' => $this->type,
+						'category' => $category,
+					));
+			}
+			// reload categories to get the proper ids.
+			$this->loadCategories();
+			// Loop through temporarily cached objectid/categoryname pairs
+			// and save relations.
+			$categories = $this->categories;
+			// For some reason this is needed or array_search(i) will return 0..?
+			ksort($categories);
+			foreach(self::$relations as $relation) {
+				$catid = $this->array_searchi($relation['category'], $categories);
+				OC_Log::write('core', __METHOD__ . 'catid, ' . $relation['category'] . ' ' . $catid, OC_Log::DEBUG);
+				if($catid) {
+					OCP\DB::insertIfNotExist(self::RELATION_TABLE,
+						array(
+							'objid' => $relation['objid'],
+							'categoryid' => $catid,
+							'type' => $this->type,
+							));
+				}
+			}
+			self::$relations = array(); // reset
 		} else {
-			OC_Log::write('core', 'OC_VCategories::save: $this->categories is not an array! '.print_r($this->categories, true), OC_Log::ERROR);
+			OC_Log::write('core', __METHOD__.', $this->categories is not an array! '
+				. print_r($this->categories, true), OC_Log::ERROR);
 		}
 	}
 
+	/**
+	* @brief Delete categories and category/object relations for a user.
+	* For hooking up on post_deleteUser
+	* @param string $uid The user id for which entries should be purged.
+	*/
+	public static function post_deleteUser($arguments) {
+		// Find all objectid/categoryid pairs.
+		$result = null;
+		try {
+			$stmt = OCP\DB::prepare('SELECT `id` FROM `' . self::CATEGORY_TABLE . '` '
+				. 'WHERE `uid` = ?');
+			$result = $stmt->execute(array($arguments['uid']));
+			if (OC_DB::isError($result)) {
+				OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+			}
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+				OCP\Util::ERROR);
+		}
+
+		if(!is_null($result)) {
+			try {
+				$stmt = OCP\DB::prepare('DELETE FROM `' . self::RELATION_TABLE . '` '
+					. 'WHERE `categoryid` = ?');
+				while( $row = $result->fetchRow()) {
+					try {
+						$stmt->execute(array($row['id']));
+					} catch(Exception $e) {
+						OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+							OCP\Util::ERROR);
+					}
+				}
+			} catch(Exception $e) {
+				OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+					OCP\Util::ERROR);
+			}
+		}
+		try {
+			$stmt = OCP\DB::prepare('DELETE FROM `' . self::CATEGORY_TABLE . '` '
+				. 'WHERE `uid` = ? AND');
+			$result = $stmt->execute(array($arguments['uid']));
+			if (OC_DB::isError($result)) {
+				OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+			}
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__ . ', exception: '
+				. $e->getMessage(), OCP\Util::ERROR);
+		}
+	}
+
+	/**
+	* @brief Delete category/object relations from the db
+	* @param int $id The id of the object
+	* @param string $type The type of object (event/contact/task/journal).
+	* 	Defaults to the type set in the instance
+	* @returns boolean Returns false on error.
+	*/
+	public function purgeObject($id, $type = null) {
+		$type = is_null($type) ? $this->type : $type;
+		try {
+			$stmt = OCP\DB::prepare('DELETE FROM `' . self::RELATION_TABLE . '` '
+					. 'WHERE `objid` = ? AND `type`= ?');
+			$result = $stmt->execute(array($id, $type));
+			if (OC_DB::isError($result)) {
+				OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+				return false;
+			}
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+				OCP\Util::ERROR);
+			return false;
+		}
+		return true;
+	}
+
+	/**
+	* Get favorites for an object type
+	*
+	* @param string $type The type of object (event/contact/task/journal).
+	* 	Defaults to the type set in the instance
+	* @returns array An array of object ids.
+	*/
+	public function getFavorites($type = null) {
+		$type = is_null($type) ? $this->type : $type;
+
+		try {
+			return $this->idsForCategory(self::CATEGORY_FAVORITE);
+		} catch(Exception $e) {
+			// No favorites
+			return array();
+		}
+	}
+
+	/**
+	* Add an object to favorites
+	*
+	* @param int $objid The id of the object
+	* @param string $type The type of object (event/contact/task/journal).
+	* 	Defaults to the type set in the instance
+	* @returns boolean
+	*/
+	public function addToFavorites($objid, $type = null) {
+		$type = is_null($type) ? $this->type : $type;
+		if(!$this->hasCategory(self::CATEGORY_FAVORITE)) {
+			$this->add(self::CATEGORY_FAVORITE, true);
+		}
+		return $this->addToCategory($objid, self::CATEGORY_FAVORITE, $type);
+	}
+
+	/**
+	* Remove an object from favorites
+	*
+	* @param int $objid The id of the object
+	* @param string $type The type of object (event/contact/task/journal).
+	* 	Defaults to the type set in the instance
+	* @returns boolean
+	*/
+	public function removeFromFavorites($objid, $type = null) {
+		$type = is_null($type) ? $this->type : $type;
+		return $this->removeFromCategory($objid, self::CATEGORY_FAVORITE, $type);
+	}
+
+	/**
+	* @brief Creates a category/object relation.
+	* @param int $objid The id of the object
+	* @param int|string $category The id or name of the category
+	* @param string $type The type of object (event/contact/task/journal).
+	* 	Defaults to the type set in the instance
+	* @returns boolean Returns false on database error.
+	*/
+	public function addToCategory($objid, $category, $type = null) {
+		$type = is_null($type) ? $this->type : $type;
+		if(is_string($category) && !is_numeric($category)) {
+			if(!$this->hasCategory($category)) {
+				$this->add($category, true);
+			}
+			$categoryid =  $this->array_searchi($category, $this->categories);
+		} else {
+			$categoryid = $category;
+		}
+		try {
+			OCP\DB::insertIfNotExist(self::RELATION_TABLE,
+				array(
+					'objid' => $objid,
+					'categoryid' => $categoryid,
+					'type' => $type,
+				));
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+				OCP\Util::ERROR);
+			return false;
+		}
+		return true;
+	}
+
+	/**
+	* @brief Delete single category/object relation from the db
+	* @param int $objid The id of the object
+	* @param int|string $category The id or name of the category
+	* @param string $type The type of object (event/contact/task/journal).
+	* 	Defaults to the type set in the instance
+	* @returns boolean
+	*/
+	public function removeFromCategory($objid, $category, $type = null) {
+		$type = is_null($type) ? $this->type : $type;
+		$categoryid = (is_string($category) && !is_numeric($category))
+			? $this->array_searchi($category, $this->categories)
+			: $category;
+		try {
+			$sql = 'DELETE FROM `' . self::RELATION_TABLE . '` '
+					. 'WHERE `objid` = ? AND `categoryid` = ? AND `type` = ?';
+			OCP\Util::writeLog('core', __METHOD__.', sql: ' . $objid . ' ' . $categoryid . ' ' . $type,
+				OCP\Util::DEBUG);
+			$stmt = OCP\DB::prepare($sql);
+			$stmt->execute(array($objid, $categoryid, $type));
+		} catch(Exception $e) {
+			OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+				OCP\Util::ERROR);
+			return false;
+		}
+		return true;
+	}
+
 	/**
 	* @brief Delete categories from the db and from all the vobject supplied
 	* @param $names An array of categories to delete
@@ -173,37 +661,87 @@ class OC_VCategories {
 		if(!is_array($names)) {
 			$names = array($names);
 		}
-		OC_Log::write('core', 'OC_VCategories::delete, before: '.print_r($this->categories, true), OC_Log::DEBUG);
+
+		OC_Log::write('core', __METHOD__ . ', before: '
+			. print_r($this->categories, true), OC_Log::DEBUG);
 		foreach($names as $name) {
-			OC_Log::write('core', 'OC_VCategories::delete: '.$name, OC_Log::DEBUG);
+			$id = null;
+			OC_Log::write('core', __METHOD__.', '.$name, OC_Log::DEBUG);
 			if($this->hasCategory($name)) {
-				//OC_Log::write('core', 'OC_VCategories::delete: '.$name.' got it', OC_Log::DEBUG);
-				unset($this->categories[$this->array_searchi($name, $this->categories)]);
+				$id = $this->array_searchi($name, $this->categories);
+				unset($this->categories[$id]);
+			}
+			try {
+				$stmt = OCP\DB::prepare('DELETE FROM `' . self::CATEGORY_TABLE . '` WHERE '
+					. '`uid` = ? AND `type` = ? AND `category` = ?');
+				$result = $stmt->execute(array($this->user, $this->type, $name));
+				if (OC_DB::isError($result)) {
+					OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+				}
+			} catch(Exception $e) {
+				OCP\Util::writeLog('core', __METHOD__ . ', exception: '
+					. $e->getMessage(), OCP\Util::ERROR);
+			}
+			if(!is_null($id) && $id !== false) {
+				try {
+					$sql = 'DELETE FROM `' . self::RELATION_TABLE . '` '
+							. 'WHERE `categoryid` = ?';
+					$stmt = OCP\DB::prepare($sql);
+					$result = $stmt->execute(array($id));
+					if (OC_DB::isError($result)) {
+						OC_Log::write('core', __METHOD__. 'DB error: ' . OC_DB::getErrorMessage($result), OC_Log::ERROR);
+					}
+				} catch(Exception $e) {
+					OCP\Util::writeLog('core', __METHOD__.', exception: '.$e->getMessage(),
+						OCP\Util::ERROR);
+					return false;
+				}
 			}
 		}
-		$this->save();
-		OC_Log::write('core', 'OC_VCategories::delete, after: '.print_r($this->categories, true), OC_Log::DEBUG);
+		OC_Log::write('core', __METHOD__.', after: '
+			. print_r($this->categories, true), OC_Log::DEBUG);
 		if(!is_null($objects)) {
 			foreach($objects as $key=>&$value) {
 				$vobject = OC_VObject::parse($value[1]);
 				if(!is_null($vobject)) {
-					$categories = $vobject->getAsArray('CATEGORIES');
-					//OC_Log::write('core', 'OC_VCategories::delete, before: '.$key.': '.print_r($categories, true), OC_Log::DEBUG);
+					$object = null;
+					$componentname = '';
+					if (isset($vobject->VEVENT)) {
+						$object = $vobject->VEVENT;
+						$componentname = 'VEVENT';
+					} else
+					if (isset($vobject->VTODO)) {
+						$object = $vobject->VTODO;
+						$componentname = 'VTODO';
+					} else
+					if (isset($vobject->VJOURNAL)) {
+						$object = $vobject->VJOURNAL;
+						$componentname = 'VJOURNAL';
+					} else {
+						$object = $vobject;
+					}
+					$categories = $object->getAsArray('CATEGORIES');
 					foreach($names as $name) {
 						$idx = $this->array_searchi($name, $categories);
-						//OC_Log::write('core', 'OC_VCategories::delete, loop: '.$name.', '.print_r($idx, true), OC_Log::DEBUG);
 						if($idx !== false) {
-							OC_Log::write('core', 'OC_VCategories::delete, unsetting: '.$categories[$this->array_searchi($name, $categories)], OC_Log::DEBUG);
+							OC_Log::write('core', __METHOD__
+								.', unsetting: '
+								. $categories[$this->array_searchi($name, $categories)],
+								OC_Log::DEBUG);
 							unset($categories[$this->array_searchi($name, $categories)]);
-							//unset($categories[$idx]);
 						}
 					}
-					//OC_Log::write('core', 'OC_VCategories::delete, after: '.$key.': '.print_r($categories, true), OC_Log::DEBUG);
-					$vobject->setString('CATEGORIES', implode(',', $categories));
+
+					$object->setString('CATEGORIES', implode(',', $categories));
+					if($vobject !== $object) {
+						$vobject[$componentname] = $object;
+					}
 					$value[1] = $vobject->serialize();
 					$objects[$key] = $value;
 				} else {
-					OC_Log::write('core', 'OC_VCategories::delete, unable to parse. ID: '.$value[0].', '.substr($value[1], 0, 50).'(...)', OC_Log::DEBUG);
+					OC_Log::write('core', __METHOD__
+						.', unable to parse. ID: ' . $value[0] . ', '
+						. substr($value[1], 0, 50) . '(...)', OC_Log::DEBUG);
 				}
 			}
 		}
@@ -224,5 +762,5 @@ class OC_VCategories {
 		}
 		return array_search(strtolower($needle), array_map('strtolower', $haystack));
 	}
-
 }
+
diff --git a/tests/data/db_structure.xml b/tests/data/db_structure.xml
index 03d7502c44179c9fe21995a0479328088f73a292..af2e5ce3439131671ca96378d8cfb1e9e97d02a1 100644
--- a/tests/data/db_structure.xml
+++ b/tests/data/db_structure.xml
@@ -135,4 +135,47 @@
 
  </table>
 
+ <table>
+
+  <name>*dbprefix*vcategory</name>
+
+  <declaration>
+
+   <field>
+    <name>id</name>
+     <type>integer</type>
+     <default>0</default>
+     <notnull>true</notnull>
+     <autoincrement>1</autoincrement>
+     <unsigned>true</unsigned>
+     <length>4</length>
+   </field>
+
+   <field>
+     <name>uid</name>
+     <type>text</type>
+     <default></default>
+     <notnull>true</notnull>
+     <length>64</length>
+    </field>
+
+   <field>
+     <name>type</name>
+     <type>text</type>
+     <default></default>
+     <notnull>true</notnull>
+     <length>64</length>
+    </field>
+
+    <field>
+     <name>category</name>
+     <type>text</type>
+     <default></default>
+     <notnull>true</notnull>
+     <length>255</length>
+    </field>
+
+  </declaration>
+ </table>
+
 </database>
diff --git a/tests/lib/db.php b/tests/lib/db.php
index 2344f7d8ec466ac129a35f101cbd406b697d0ebf..c2eb38dae8367ba1a174305539db0c4610917557 100644
--- a/tests/lib/db.php
+++ b/tests/lib/db.php
@@ -24,6 +24,7 @@ class Test_DB extends UnitTestCase {
 		$this->test_prefix = $r;
 		$this->table1 = $this->test_prefix.'contacts_addressbooks';
 		$this->table2 = $this->test_prefix.'contacts_cards';
+		$this->table3 = $this->test_prefix.'vcategory';
 	}
 
 	public function tearDown() {
@@ -67,4 +68,66 @@ class Test_DB extends UnitTestCase {
 		$result = $query->execute(array('uri_3'));
 		$this->assertTrue($result);
 	}
+
+	public function testinsertIfNotExist() {
+		$categoryentries = array(
+				array('user' => 'test', 'type' => 'contact', 'category' => 'Family'),
+				array('user' => 'test', 'type' => 'contact', 'category' => 'Friends'),
+				array('user' => 'test', 'type' => 'contact', 'category' => 'Coworkers'),
+				array('user' => 'test', 'type' => 'contact', 'category' => 'Coworkers'),
+				array('user' => 'test', 'type' => 'contact', 'category' => 'School'),
+			);
+
+		foreach($categoryentries as $entry) {
+			$result = OC_DB::insertIfNotExist('*PREFIX*'.$this->table3,
+				array(
+					'uid' => $entry['user'],
+					'type' => $entry['type'],
+					'category' => $entry['category'],
+				));
+			$this->assertTrue($result);
+		}
+
+		$query = OC_DB::prepare('SELECT * FROM *PREFIX*'.$this->table3);
+		$result = $query->execute();
+		$this->assertTrue($result);
+		$this->assertEqual('4', $result->numRows());
+	}
+
+	public function testinsertIfNotExistDontOverwrite() {
+		$fullname = 'fullname test';
+		$uri = 'uri_1';
+		$carddata = 'This is a vCard';
+
+		// Normal test to have same known data inserted.
+		$query = OC_DB::prepare('INSERT INTO *PREFIX*'.$this->table2.' (`fullname`, `uri`, `carddata`) VALUES (?, ?, ?)');
+		$result = $query->execute(array($fullname, $uri, $carddata));
+		$this->assertTrue($result);
+		$query = OC_DB::prepare('SELECT `fullname`, `uri`, `carddata` FROM *PREFIX*'.$this->table2.' WHERE `uri` = ?');
+		$result = $query->execute(array($uri));
+		$this->assertTrue($result);
+		$row = $result->fetchRow();
+		$this->assertArrayHasKey('carddata', $row);
+		$this->assertEqual($carddata, $row['carddata']);
+		$this->assertEqual('1', $result->numRows());
+
+		// Try to insert a new row
+		$result = OC_DB::insertIfNotExist('*PREFIX*'.$this->table2,
+			array(
+				'fullname' => $fullname,
+				'uri' => $uri,
+			));
+		$this->assertTrue($result);
+
+		$query = OC_DB::prepare('SELECT `fullname`, `uri`, `carddata` FROM *PREFIX*'.$this->table2.' WHERE `uri` = ?');
+		$result = $query->execute(array($uri));
+		$this->assertTrue($result);
+		$row = $result->fetchRow();
+		$this->assertArrayHasKey('carddata', $row);
+		// Test that previously inserted data isn't overwritten
+		$this->assertEqual($carddata, $row['carddata']);
+		// And that a new row hasn't been inserted.
+		$this->assertEqual('1', $result->numRows());
+
+	}
 }
diff --git a/tests/lib/vcategories.php b/tests/lib/vcategories.php
new file mode 100644
index 0000000000000000000000000000000000000000..63516a063daa62f4cbe37f7054ef9626c0153546
--- /dev/null
+++ b/tests/lib/vcategories.php
@@ -0,0 +1,117 @@
+<?php
+/**
+* ownCloud
+*
+* @author Thomas Tanghus
+* @copyright 2012 Thomas Tanghus (thomas@tanghus.net)
+*
+* This library is free software; you can redistribute it and/or
+* modify it under the terms of the GNU AFFERO GENERAL PUBLIC LICENSE
+* License as published by the Free Software Foundation; either
+* version 3 of the License, or any later version.
+*
+* This library is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+* GNU AFFERO GENERAL PUBLIC LICENSE for more details.
+*
+* You should have received a copy of the GNU Affero General Public
+* License along with this library.  If not, see <http://www.gnu.org/licenses/>.
+*
+*/
+
+//require_once("../lib/template.php");
+
+class Test_VCategories extends UnitTestCase {
+
+	protected $objectType;
+	protected $user;
+	protected $backupGlobals = FALSE;
+
+	public function setUp() {
+
+		OC_User::clearBackends();
+		OC_User::useBackend('dummy');
+		$this->user = uniqid('user_');
+		$this->objectType = uniqid('type_');
+		OC_User::createUser($this->user, 'pass');
+		OC_User::setUserId($this->user);
+
+	}
+
+	public function tearDown() {
+		//$query = OC_DB::prepare('DELETE FROM `*PREFIX*vcategories` WHERE `item_type` = ?');
+		//$query->execute(array('test'));
+	}
+
+	public function testInstantiateWithDefaults() {
+		$defcategories = array('Friends', 'Family', 'Work', 'Other');
+
+		$catmgr = new OC_VCategories($this->objectType, $this->user, $defcategories);
+
+		$this->assertEqual(4, count($catmgr->categories()));
+	}
+
+	public function testAddCategories() {
+		$categories = array('Friends', 'Family', 'Work', 'Other');
+
+		$catmgr = new OC_VCategories($this->objectType, $this->user);
+
+		foreach($categories as $category) {
+			$result = $catmgr->add($category);
+			$this->assertTrue($result);
+		}
+
+		$this->assertFalse($catmgr->add('Family'));
+		$this->assertFalse($catmgr->add('fAMILY'));
+
+		$this->assertEqual(4, count($catmgr->categories()));
+	}
+
+	public function testdeleteCategories() {
+		$defcategories = array('Friends', 'Family', 'Work', 'Other');
+		$catmgr = new OC_VCategories($this->objectType, $this->user, $defcategories);
+		$this->assertEqual(4, count($catmgr->categories()));
+
+		$catmgr->delete('family');
+		$this->assertEqual(3, count($catmgr->categories()));
+
+		$catmgr->delete(array('Friends', 'Work', 'Other'));
+		$this->assertEqual(0, count($catmgr->categories()));
+
+	}
+
+	public function testAddToCategory() {
+		$objids = array(1, 2, 3, 4, 5, 6, 7, 8, 9);
+
+		$catmgr = new OC_VCategories($this->objectType, $this->user);
+
+		foreach($objids as $id) {
+			$catmgr->addToCategory($id, 'Family');
+		}
+
+		$this->assertEqual(1, count($catmgr->categories()));
+		$this->assertEqual(9, count($catmgr->idsForCategory('Family')));
+	}
+
+	/**
+	* @depends testAddToCategory
+	*/
+	public function testRemoveFromCategory() {
+		$objids = array(1, 2, 3, 4, 5, 6, 7, 8, 9);
+
+		// Is this "legal"?
+		$this->testAddToCategory();
+		$catmgr = new OC_VCategories($this->objectType, $this->user);
+
+		foreach($objids as $id) {
+			$this->assertTrue(in_array($id, $catmgr->idsForCategory('Family')));
+			$catmgr->removeFromCategory($id, 'Family');
+			$this->assertFalse(in_array($id, $catmgr->idsForCategory('Family')));
+		}
+
+		$this->assertEqual(1, count($catmgr->categories()));
+		$this->assertEqual(0, count($catmgr->idsForCategory('Family')));
+	}
+
+}