diff --git a/data-dashboard-backend/src/main/java/org/radarbase/datadashboard/api/domain/model/Observation.kt b/data-dashboard-backend/src/main/java/org/radarbase/datadashboard/api/domain/model/Observation.kt
index 2b4378e..c642f31 100644
--- a/data-dashboard-backend/src/main/java/org/radarbase/datadashboard/api/domain/model/Observation.kt
+++ b/data-dashboard-backend/src/main/java/org/radarbase/datadashboard/api/domain/model/Observation.kt
@@ -43,7 +43,6 @@ data class Observation(
     @Id
     val topic: String,
 
-    @Id
     val category: String,
 
     @Column(nullable = false)