diff --git a/application/dashboard/models.py b/application/dashboard/models.py
index 80f82d5..f2b86b2 100644
--- a/application/dashboard/models.py
+++ b/application/dashboard/models.py
@@ -6,7 +6,7 @@ from application import db
 class Plate(db.Model):
     __abstract__ = True
     id = db.Column(db.Integer, primary_key=True)
-    plate = db.Column(db.String(40), unique=True, nullable=False)
+    plate = db.Column(db.String(40), nullable=False)
 
 
 class LoggedItem(Plate):
@@ -27,6 +27,7 @@ class LoggedItem(Plate):
 
 class AllowedPlate(Plate):
     __tablename__ = "AllowedPlates"
+    __table_args__ = (db.UniqueConstraint("plate"),)
 
     def __init__(self, plate: str):
         self.plate = plate