diff --git a/models/conversations/comment.go b/models/conversations/comment.go
index e458803e4a16..72edf6a43257 100644
--- a/models/conversations/comment.go
+++ b/models/conversations/comment.go
@@ -124,8 +124,8 @@ type ConversationComment struct {
 	Content        string `xorm:"LONGTEXT"`
 	ContentVersion int    `xorm:"NOT NULL DEFAULT 0"`
 
-	ConversationID int64 `xorm:"INDEX"`
-	Conversation   *Conversation
+	ConversationID int64         `xorm:"INDEX"`
+	Conversation   *Conversation `xorm:"-"`
 
 	CreatedUnix timeutil.TimeStamp `xorm:"INDEX created"`
 	UpdatedUnix timeutil.TimeStamp `xorm:"INDEX updated"`
diff --git a/models/conversations/conversation.go b/models/conversations/conversation.go
index cff9cdf13aab..1414b35d4d1c 100644
--- a/models/conversations/conversation.go
+++ b/models/conversations/conversation.go
@@ -94,6 +94,9 @@ var ErrConversationAlreadyChanged = util.NewInvalidArgumentErrorf("the conversat
 
 type ConversationType int
 
+// CommentTypeUndefined is used to search for comments of any type
+const ConversationTypeUndefined CommentType = -1
+
 const (
 	ConversationTypeCommit ConversationType = iota
 )