diff --git a/ogn/model/__init__.py b/ogn/model/__init__.py
index add61fa..e83b673 100644
--- a/ogn/model/__init__.py
+++ b/ogn/model/__init__.py
@@ -10,5 +10,6 @@ from .receiver_beacon import ReceiverBeacon
 from .receiver import Receiver
 from .takeoff_landing import TakeoffLanding
 from .airport import Airport
+from .logbook import Logbook
 
 from .geo import Location
diff --git a/ogn/model/logbook.py b/ogn/model/logbook.py
index c235fc9..4902dcf 100644
--- a/ogn/model/logbook.py
+++ b/ogn/model/logbook.py
@@ -2,16 +2,10 @@ from sqlalchemy import Integer, DateTime, Interval, Column, ForeignKey
 from sqlalchemy.orm import relationship
 
 from .base import Base
-from sqlalchemy.sql.schema import UniqueConstraint
 
 
 class Logbook(Base):
     __tablename__ = 'logbook'
-    __table_args__ = (UniqueConstraint('reftime',
-                                       'takeoff_airport_id',
-                                       'landing_airport_id',
-                                       'device_id'),
-                      )
 
     id = Column(Integer, primary_key=True)