diff --git a/src/function/sync/apply-actions/dispatch-helper/helper.ts b/src/function/sync/apply-actions/dispatch-helper/helper.ts
index 7fb000f..4de6d25 100644
--- a/src/function/sync/apply-actions/dispatch-helper/helper.ts
+++ b/src/function/sync/apply-actions/dispatch-helper/helper.ts
@@ -15,8 +15,10 @@
  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  */
 
+import { ForeignKeyConstraintError, UniqueConstraintError } from 'sequelize'
 import { ClientPushChangesRequestAction } from '../../../../api/schema'
 import { EventHandler } from '../../../../monitoring/eventhandler'
+import { ApplyActionDatabaseException } from '../exception/database'
 import { ApplyActionException } from '../exception/index'
 import { EncodedActionSchemaMismatchException } from '../exception/invalidaction'
 import { parseEncodedAction } from '../parse-encoded-action'
@@ -40,7 +42,19 @@ export async function dispatch<T1 extends { type: string }, T2> ({ type, action,
   try {
     const parsedAction = parser(parsedSerializedAction)
 
-    await applier(parsedAction)
+    try {
+      await applier(parsedAction)
+    } catch (ex) {
+      if (ex instanceof UniqueConstraintError) {
+        throw new ApplyActionDatabaseException({
+          staticMessage: 'database unique constraint violation of the fields ' + Object.keys(ex.fields).join(', ')
+        })
+      } else if (ex instanceof ForeignKeyConstraintError) {
+        throw new ApplyActionDatabaseException({
+          staticMessage: 'database foreign key violation at the table ' + ex.table + '/' + ex.index
+        })
+      } else throw ex
+    }
 
     eventHandler.countEvent('dispatched action:' + actionType)
   } catch (ex) {
diff --git a/src/function/sync/apply-actions/exception/database.ts b/src/function/sync/apply-actions/exception/database.ts
new file mode 100644
index 0000000..a310dc0
--- /dev/null
+++ b/src/function/sync/apply-actions/exception/database.ts
@@ -0,0 +1,20 @@
+/*
+ * server component for the TimeLimit App
+ * Copyright (C) 2019 - 2020 Jonas Lochmann
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, version 3 of the License.
+ *
+ * This program 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 program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import { ApplyActionException } from './index'
+
+export class ApplyActionDatabaseException extends ApplyActionException {}