diff --git a/backend/v3/storage/database/errors.go b/backend/v3/storage/database/errors.go
index 4504efb1ae..7a148e4d54 100644
--- a/backend/v3/storage/database/errors.go
+++ b/backend/v3/storage/database/errors.go
@@ -66,7 +66,6 @@ const (
 	IntegrityTypeUnique  IntegrityType = "unique"
 	IntegrityTypeForeign IntegrityType = "foreign"
 	IntegrityTypeNotNull IntegrityType = "not null"
-	IntegrityTypeUnknown IntegrityType = "unknown"
 )
 
 // IntegrityViolationError represents a generic integrity violation error.