diff --git a/model/rid.go b/model/rid.go
index 8af5a9d67e517b9ac8605f23aaec173c3e38bacc..818c1856a1f266e8f67e6ae96fab334b15fd6193 100644
--- a/model/rid.go
+++ b/model/rid.go
@@ -16,28 +16,37 @@ 	WithPadding(base32.NoPadding)
 
 // An RID is a unique resource ID.
 type RID struct {
-	uuid uuid.UUID
+	uuid uuid.NullUUID
 }
 
 // Creates a new resource ID.
 func NewRID() RID {
-	uuid, err := uuid.NewV7()
+	uu, err := uuid.NewV7()
 	if err != nil {
 		panic(err)
 	}
 	return RID{
-		uuid: uuid,
+		uuid: uuid.NullUUID{
+			UUID:  uu,
+			Valid: true,
+		},
 	}
 }
 
 // Returns the UUID representation of this RID.
 func (rid *RID) UUID() uuid.UUID {
-	return rid.uuid
+	if !rid.uuid.Valid {
+		panic(fmt.Errorf("invalid UUID"))
+	}
+	return rid.uuid.UUID
 }
 
 // Returns the string representation of this RID.
 func (rid *RID) String() string {
-	return base32Encoding.EncodeToString(rid.uuid[:])
+	if !rid.uuid.Valid {
+		return ""
+	}
+	return base32Encoding.EncodeToString(rid.uuid.UUID[:])
 }
 
 func (rid RID) MarshalGQL(w io.Writer) {
@@ -45,14 +54,20 @@ 	w.Write(fmt.Appendf(nil, `"%s"`, rid.String()))
 }
 
 func (rid *RID) unmarshalString(s string) error {
+	if len(s) == 0 {
+		rid.uuid.Valid = false
+		return nil
+	}
 	bytes, err := base32Encoding.DecodeString(s)
 	if err != nil {
 		return err
 	}
-	rid.uuid, err = uuid.FromBytes(bytes)
+	rid.uuid.UUID, err = uuid.FromBytes(bytes)
 	if err != nil {
+		rid.uuid.Valid = false
 		return err
 	}
+	rid.uuid.Valid = true
 	return nil
 }
 
@@ -71,17 +86,11 @@ 	switch src := src.(type) {
 	case string:
 		return rid.unmarshalString(src)
 	default:
-		var uuid uuid.UUID
-		err := uuid.Scan(src)
-		if err != nil {
-			return err
-		}
-		rid.uuid = uuid
-		return nil
+		return rid.uuid.Scan(src)
 	}
 }
 
 // database/sql/driver.Valuer
 func (rid RID) Value() (driver.Value, error) {
-	return rid.UUID().Value()
+	return rid.uuid.Value()
 }