diff --git a/core/core.pro b/core/core.pro
index bdd8b7e..509247f 100644
--- a/core/core.pro
+++ b/core/core.pro
@@ -42,7 +42,8 @@ SOURCES += \
     samestringvalidator.cpp \
     savefilterdialog.cpp \
     filterdialog.cpp \
-    itablemodel.cpp
+    itablemodel.cpp \
+    iservice.cpp
 
 HEADERS += core.h\
         core_global.h \
@@ -82,7 +83,8 @@ HEADERS += core.h\
     savefilterdialog.h \
     filterdialog.h \
     itablemodel.h \
-    data/core_global.h
+    data/core_global.h \
+    iservice.h
 
 unix {
     target.path = /usr/lib
diff --git a/core/iplugin.h b/core/iplugin.h
index 990fa44..6a1605b 100644
--- a/core/iplugin.h
+++ b/core/iplugin.h
@@ -58,7 +58,7 @@ public:
 
 protected:
     QWidget *m_ui;
-    void *m_service;
+    IService *m_service;
 };
 
 #define PluginInterface_iid "cz.itsolved.prodejna.IPlugin"
diff --git a/core/iservice.cpp b/core/iservice.cpp
new file mode 100644
index 0000000..281d46b
--- /dev/null
+++ b/core/iservice.cpp
@@ -0,0 +1,12 @@
+#include "iservice.h"
+
+IService::IService(QObject *parent) : QObject(parent)
+{
+
+}
+
+IService::~IService()
+{
+
+}
+
diff --git a/core/iservice.h b/core/iservice.h
new file mode 100644
index 0000000..eabc038
--- /dev/null
+++ b/core/iservice.h
@@ -0,0 +1,25 @@
+#ifndef ISERVICE_H
+#define ISERVICE_H
+
+#include <QObject>
+#include <QString>
+
+#include "core_global.h"
+
+class CORESHARED_EXPORT IService : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit IService(QObject *parent = 0);
+    virtual ~IService();
+
+signals:
+    void dbError(QString errMsg);
+    void dataChanged();
+    void permissionDenied();
+
+public slots:
+};
+
+#endif // ISERVICE_H
diff --git a/core/service.h b/core/service.h
index f56207e..e6d1f48 100644
--- a/core/service.h
+++ b/core/service.h
@@ -12,14 +12,15 @@
 
 #include "core_global.h"
 #include "context.h"
+#include "iservice.h"
 
 #include "transaction.h"
 
 template<class T>
-class Service
+class Service : public IService
 {
 public:
-    Service() { }
+    explicit Service(QObject *parent = NULL) :IService(parent) { }
 
     explicit Service(const QString &pluginId) {
         m_pluginId = pluginId;
@@ -31,14 +32,23 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        odb::result<T> res = db->template query<T>();
-
         QList<QSharedPointer<T> > ret;
-        for (typename odb::result<T>::iterator it = res.begin(); it != res.end(); it++) {
-            ret.append(it.load());
+
+        try
+        {
+            odb::result<T> res = db->template query<T>();
+
+            for (typename odb::result<T>::iterator it = res.begin(); it != res.end(); it++) {
+                ret.append(it.load());
+            }
+
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
         }
 
-        tx.commit();
         return ret;
     }
 
@@ -48,8 +58,19 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        db->persist(entity);
-        tx.commit();
+
+        try
+        {
+            db->persist(entity);
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
+            return;
+        }
+
+        emit dataChanged();
     }
 
     void update(QSharedPointer<T> entity) {
@@ -58,8 +79,18 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        db->update(entity);
-        tx.commit();
+
+        try
+        {
+            db->update(entity);
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
+        }
+
+        emit dataChanged();
     }
 
     QSharedPointer<T> loadById(int id) {
@@ -68,8 +99,18 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        QSharedPointer<T> entity = db->template load<T>(id);
-        tx.commit();
+        QSharedPointer<T> entity;
+
+        try
+        {
+            entity = db->template load<T>(id);
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
+        }
+
         return entity;
     }
 
@@ -79,8 +120,16 @@ public:
         Q_ASSERT(db);
 
         Transaction tx;
-        db->erase(entity);
-        tx.commit();
+
+        try
+        {
+            db->erase(entity);
+            tx.commit();
+        }
+        catch (const odb::exception &ex)
+        {
+            emit dbError(ex.what());
+        }
     }
 
     void setPluginId(const QString &pluginId) {