diff --git a/src/main/java/at/ionas999/health/controller/MedicalPracticeController.java b/src/main/java/at/ionas999/health/controller/MedicalPracticeController.java
index 8c9806f..9423167 100644
--- a/src/main/java/at/ionas999/health/controller/MedicalPracticeController.java
+++ b/src/main/java/at/ionas999/health/controller/MedicalPracticeController.java
@@ -32,6 +32,7 @@ public class MedicalPracticeController implements ChangeObserver<WaitingRoom> {
 
     @Override
     public void update(WaitingRoom subject) {
+
         waitingRoomTextField.setText(waitingRoom.getPatients().stream()
                 .reduce("", (s, p) -> s + p + "\n", String::concat));
         preparation.setText(waitingRoom.getPatientInPreparation() == null ? "" : waitingRoom.getPatientInPreparation().toString());
diff --git a/src/main/java/at/ionas999/health/repositories/WaitingRoom.java b/src/main/java/at/ionas999/health/repositories/WaitingRoom.java
index 90712f9..5fc8cb5 100644
--- a/src/main/java/at/ionas999/health/repositories/WaitingRoom.java
+++ b/src/main/java/at/ionas999/health/repositories/WaitingRoom.java
@@ -52,6 +52,12 @@ public class WaitingRoom {
     }
 
     public void addPatient(String name, LocalDateTime appointment, boolean isEmergency) {
+        if((this.patientUndergoingTreatment != null && this.patientUndergoingTreatment.getName().equals(name)) ||
+                this.patients.stream().anyMatch(x -> x.getName().equals(name)))
+        {
+            return;
+        }
+
         Patient patient = new Patient(name, appointment, isEmergency);
         patients.add(patient);
         patientService.AddPatient(patient);
diff --git a/src/main/java/at/ionas999/health/services/PatientService.java b/src/main/java/at/ionas999/health/services/PatientService.java
index 19f2689..45681b3 100644
--- a/src/main/java/at/ionas999/health/services/PatientService.java
+++ b/src/main/java/at/ionas999/health/services/PatientService.java
@@ -16,7 +16,7 @@ public class PatientService extends DatabaseUtilsBase implements TableCreation {
         String createTableSmt = "CREATE TABLE Patient (\n" +
                 "    name VARCHAR(255) NOT NULL PRIMARY KEY,\n" +
                 "    appointment TIMESTAMP,\n" +
-                "    isEmergency BOOLEAN\n" +
+                "    isEmergency BOOLEAN NOT NULL\n" +
                 ")";
         connection.createStatement().executeQuery(createTableSmt);
     }