diff -r 4f912cd42876 -r 86b5d8a1662f src/main/java/de/uapcore/lightpit/modules/UsersModule.java
--- a/src/main/java/de/uapcore/lightpit/modules/UsersModule.java	Fri Nov 06 10:50:32 2020 +0100
+++ b/src/main/java/de/uapcore/lightpit/modules/UsersModule.java	Thu Nov 19 13:58:54 2020 +0100
@@ -32,7 +32,7 @@
 import de.uapcore.lightpit.Constants;
 import de.uapcore.lightpit.HttpMethod;
 import de.uapcore.lightpit.RequestMapping;
-import de.uapcore.lightpit.dao.DataAccessObjects;
+import de.uapcore.lightpit.dao.DaoProvider;
 import de.uapcore.lightpit.entities.User;
 import de.uapcore.lightpit.viewmodel.UsersEditView;
 import de.uapcore.lightpit.viewmodel.UsersView;
@@ -61,7 +61,7 @@
     }
 
     @RequestMapping(method = HttpMethod.GET)
-    public void index(HttpServletRequest req, HttpServletResponse resp, DataAccessObjects dao) throws SQLException, ServletException, IOException {
+    public void index(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws SQLException, ServletException, IOException {
         final var userDao = dao.getUserDao();
 
         final var viewModel = new UsersView();
@@ -73,7 +73,7 @@
     }
 
     @RequestMapping(requestPath = "edit", method = HttpMethod.GET)
-    public void edit(HttpServletRequest req, HttpServletResponse resp, DataAccessObjects dao) throws SQLException, ServletException, IOException {
+    public void edit(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws SQLException, ServletException, IOException {
 
         final var viewModel = new UsersEditView();
         viewModel.setUser(findByParameter(req, Integer.class, "id",
@@ -86,7 +86,7 @@
     }
 
     @RequestMapping(requestPath = "commit", method = HttpMethod.POST)
-    public void commit(HttpServletRequest req, HttpServletResponse resp, DataAccessObjects dao) throws ServletException, IOException {
+    public void commit(HttpServletRequest req, HttpServletResponse resp, DaoProvider dao) throws ServletException, IOException {
 
         User user = new User(-1);
         try {
@@ -96,13 +96,19 @@
             getParameter(req, String.class, "lastname").ifPresent(user::setLastname);
             getParameter(req, String.class, "mail").ifPresent(user::setMail);
 
-            dao.getUserDao().saveOrUpdate(user);
+            final var userDao = dao.getUserDao();
+            if (user.getId() > 0) {
+                // TODO: unused return value
+                userDao.update(user);
+            } else {
+                userDao.save(user);
+            }
 
             setRedirectLocation(req, "./teams/");
             setContentPage(req, Constants.JSP_COMMIT_SUCCESSFUL);
 
             LOG.debug("Successfully updated user {}", user.getUsername());
-        } catch (NoSuchElementException | IllegalArgumentException | SQLException ex) {
+        } catch (NoSuchElementException | IllegalArgumentException ex) {
             final var viewModel = new UsersEditView();
             viewModel.setUser(user);
             // TODO: viewModel.setErrorText()