diff --git a/hamstertools/db.py b/hamstertools/db.py
index 67ed5d6..c22c594 100644
--- a/hamstertools/db.py
+++ b/hamstertools/db.py
@@ -88,7 +88,7 @@ class HamsterActivityKimaiMapping(Model):
 
 
 class HamsterFactKimaiImport(Model):
-    hamster_fact = ForeignKeyField(HamsterFact, backref="mappings")
+    hamster_fact = ForeignKeyField(HamsterFact, backref="imports")
     kimai_id = SmallIntegerField()
     imported = DateTimeField(default=datetime.now)
 
diff --git a/scripts/apitest.py b/scripts/apitest.py
index 266409a..98bc63f 100644
--- a/scripts/apitest.py
+++ b/scripts/apitest.py
@@ -6,7 +6,7 @@ sys.path.append(os.path.join(os.path.dirname(__file__), ".."))
 from datetime import datetime, timedelta
 import logging
 
-from hamstertools.kimai import *
+from hamstertools.kimai import KimaiAPI, Timesheet, Project, Activity
 
 logging.basicConfig()
 logging.getLogger().setLevel(logging.DEBUG)
diff --git a/scripts/upload.py b/scripts/upload.py
index fdeb772..caae2a4 100644
--- a/scripts/upload.py
+++ b/scripts/upload.py
@@ -7,8 +7,13 @@ from datetime import datetime
 
 from peewee import JOIN
 
-from hamstertools.db import *
-from hamstertools.kimai import *
+from hamstertools.db import (
+    HamsterCategory,
+    HamsterActivity,
+    HamsterFact,
+    HamsterFactKimaiImport,
+)
+from hamstertools.kimai import KimaiAPI, Timesheet, Project, Activity
 
 api = KimaiAPI()
 
@@ -53,6 +58,13 @@ for f in facts:
         )
         has_errors = True
         continue
+    if f.imports.count() > 0:
+        print(
+            f"fact {f.id}: activity @{f.activity.id} {f.activity.name} was already imported {f.imports.count()} time(s)"
+        )
+        has_errors = True
+        continue
+
 
 # if has_errors:
 #     sys.exit(1)
@@ -66,6 +78,13 @@ for f in facts:
             f"no mapping, skipping {f.id} ({f.activity.category.name} » {f.activity.name})"
         )
         continue
+
+    if f.imports.count() > 0:
+        print(
+            f"already imported, skipping {f.id} ({f.activity.category.name} » {f.activity.name})"
+        )
+        continue
+
     t = Timesheet(
         api,
         activity=mapping.kimai_activity,