diff --git a/src/logic/database/Crud.py b/src/logic/database/Crud.py
index 6b765ad9da9926de66b630cf43fd3c3561e41daf..d3842200515498a02c4d1f6c386668e2e4bdd1d2 100644
--- a/src/logic/database/Crud.py
+++ b/src/logic/database/Crud.py
@@ -1,4 +1,5 @@
 from datetime import datetime
+from typing import List
 
 from sqlalchemy import and_
 from sqlalchemy.orm import Session
@@ -27,7 +28,7 @@ def notify_backup_service(backupService: BackupService):
 # ===== devices =====
 
 
-def get_devices(db: Session, skip: int = 0, limit: int = 100):
+def get_devices(db: Session, skip: int = 0, limit: int = 100) -> List[Models.Device]:
     return db.query(Models.Device).offset(skip).limit(limit).all()
 
 
@@ -35,12 +36,12 @@ def get_device(db: Session, deviceId: int) -> Models.Device:
     return db.query(Models.Device).filter(Models.Device.id == deviceId).first()
 
 
-def get_device_by_name(db: Session, name: str):
+def get_device_by_name(db: Session, name: str) -> Models.Device:
     return db.query(Models.Device).filter(Models.Device.name == name).first()
 
 
 @notify_backup_service(BACKUP_SERVICE)
-def create_device(db: Session, device: Schemas.DeviceCreate):
+def create_device(db: Session, device: Schemas.DeviceCreate) -> Models.Device:
     dbDevice = Models.Device(name=device.name)
     db.add(dbDevice)
     db.commit()
@@ -49,7 +50,7 @@ def create_device(db: Session, device: Schemas.DeviceCreate):
 
 
 @notify_backup_service(BACKUP_SERVICE)
-def update_device(db: Session, deviceId: int, device: Schemas.DeviceCreate):
+def update_device(db: Session, deviceId: int, device: Schemas.DeviceCreate) -> Models.Device:
     existingDevice = get_device(db, deviceId)
     existingDevice.name = device.name
     db.commit()
@@ -65,21 +66,21 @@ def delete_device(db: Session, device: Schemas.Device):
 
 # ===== sensors =====
 
-def get_sensors(db: Session, skip: int = 0, limit: int = 100):
+def get_sensors(db: Session, skip: int = 0, limit: int = 100) -> List[Models.Sensor]:
     return db.query(Models.Sensor).offset(skip).limit(limit).all()
 
 
-def get_sensor(db: Session, sensorId: int):
+def get_sensor(db: Session, sensorId: int) -> Models.Sensor:
     return db.query(Models.Sensor).filter(Models.Sensor.id == sensorId).first()
 
 
-def get_sensor_by_name_and_device_id(db: Session, sensorName: str, deviceId: int):
-    return db.query(Models.Sensor).filter(
-        Models.Sensor.name == sensorName and Models.Sensor.deviceId == deviceId).first()
+def get_sensor_by_name_and_device_id(db: Session, sensorName: str, deviceId: int) -> Models.Sensor:
+    return db.query(Models.Sensor).filter(and_(Models.Sensor.name == sensorName,
+                                               Models.Sensor.deviceId == deviceId)).first()
 
 
 @notify_backup_service(BACKUP_SERVICE)
-def create_sensor(db: Session, sensor: Schemas.SensorCreate):
+def create_sensor(db: Session, sensor: Schemas.SensorCreate) -> Models.Sensor:
     dbSensor = Models.Sensor(**sensor.dict())
     db.add(dbSensor)
     db.commit()
@@ -88,7 +89,7 @@ def create_sensor(db: Session, sensor: Schemas.SensorCreate):
 
 
 @notify_backup_service(BACKUP_SERVICE)
-def update_sensor(db: Session, sensorId: int, sensor: Schemas.SensorUpdate):
+def update_sensor(db: Session, sensorId: int, sensor: Schemas.SensorUpdate) -> Models.Sensor:
     existingSensor = get_sensor(db, sensorId)
     existingSensor.name = sensor.name
     existingSensor.type = sensor.type
@@ -105,7 +106,7 @@ def delete_sensor(db: Session, sensor: Schemas.Sensor):
 
 # ===== measurements =====
 
-def get_measurements(db: Session, startDateTime: str, endDateTime: str):
+def get_measurements(db: Session, startDateTime: str, endDateTime: str) -> List[Models.Measurement]:
     if startDateTime and endDateTime:
         return db.query(Models.Measurement).filter(and_(startDateTime <= Models.Measurement.timestamp,
                                                         endDateTime >= Models.Measurement.timestamp)).all()
@@ -113,7 +114,8 @@ def get_measurements(db: Session, startDateTime: str, endDateTime: str):
     return db.query(Models.Measurement).all()
 
 
-def get_measurements_for_sensor(db: Session, startDateTime: str, endDateTime: str, sensorId: int):
+def get_measurements_for_sensor(db: Session, startDateTime: str,
+                                endDateTime: str, sensorId: int) -> List[Models.Measurement]:
     if startDateTime and endDateTime:
         return db.query(Models.Measurement).filter(and_(startDateTime <= Models.Measurement.timestamp,
                                                         endDateTime >= Models.Measurement.timestamp,
@@ -122,19 +124,19 @@ def get_measurements_for_sensor(db: Session, startDateTime: str, endDateTime: st
     return db.query(Models.Measurement).filter(Models.Measurement.sensorId == sensorId).all()
 
 
-def get_latest_measurement_for_sensor(db: Session, sensorId: int):
+def get_latest_measurement_for_sensor(db: Session, sensorId: int) -> Models.Measurement:
     return db.query(Models.Measurement) \
         .filter(Models.Measurement.sensorId == sensorId) \
         .order_by(Models.Measurement.timestamp.desc()) \
         .first()
 
 
-def get_measurement(db: Session, measurementId: int):
+def get_measurement(db: Session, measurementId: int) -> Models.Measurement:
     return db.query(Models.Measurement).filter(Models.Measurement.id == measurementId).first()
 
 
 @notify_backup_service(BACKUP_SERVICE)
-def create_measurement(db: Session, measurement: Schemas.MeasurementCreate):
+def create_measurement(db: Session, measurement: Schemas.MeasurementCreate) -> Models.Measurement:
     dbMeasurement = Models.Measurement(**measurement.dict(), timestamp=__get_current_datetime())
     db.add(dbMeasurement)
     db.commit()