diff --git a/libcockatrice_models/libcockatrice/models/database/card_database_model.cpp b/libcockatrice_models/libcockatrice/models/database/card_database_model.cpp
index 5ef84a276..253dcd134 100644
--- a/libcockatrice_models/libcockatrice/models/database/card_database_model.cpp
+++ b/libcockatrice_models/libcockatrice/models/database/card_database_model.cpp
@@ -81,7 +81,7 @@ QVariant CardDatabaseModel::headerData(int section, Qt::Orientation orientation,
     }
 }
 
-void CardDatabaseModel::cardInfoChanged(CardInfoPtr card)
+void CardDatabaseModel::cardInfoChanged(const CardInfoPtr &card)
 {
     const int row = cardList.indexOf(card);
     if (row == -1) {
@@ -91,7 +91,7 @@ void CardDatabaseModel::cardInfoChanged(CardInfoPtr card)
     emit dataChanged(index(row, 0), index(row, CARDDBMODEL_COLUMNS - 1));
 }
 
-bool CardDatabaseModel::checkCardHasAtLeastOneEnabledSet(CardInfoPtr card)
+bool CardDatabaseModel::checkCardHasAtLeastOneEnabledSet(const CardInfoPtr &card) const
 {
     if (!showOnlyCardsFromEnabledSets) {
         return true;
@@ -125,7 +125,7 @@ void CardDatabaseModel::cardDatabaseEnabledSetsChanged()
     }
 }
 
-void CardDatabaseModel::cardAdded(CardInfoPtr card)
+void CardDatabaseModel::cardAdded(const CardInfoPtr &card)
 {
     if (checkCardHasAtLeastOneEnabledSet(card)) {
         // add the card if it's present in at least one enabled set
diff --git a/libcockatrice_models/libcockatrice/models/database/card_database_model.h b/libcockatrice_models/libcockatrice/models/database/card_database_model.h
index 218cfff92..8655389d7 100644
--- a/libcockatrice_models/libcockatrice/models/database/card_database_model.h
+++ b/libcockatrice_models/libcockatrice/models/database/card_database_model.h
@@ -51,11 +51,11 @@ private:
     CardDatabase *db;
     bool showOnlyCardsFromEnabledSets;
 
-    inline bool checkCardHasAtLeastOneEnabledSet(CardInfoPtr card);
+    inline bool checkCardHasAtLeastOneEnabledSet(const CardInfoPtr &card) const;
 private slots:
-    void cardAdded(CardInfoPtr card);
+    void cardAdded(const CardInfoPtr &card);
     void cardRemoved(CardInfoPtr card);
-    void cardInfoChanged(CardInfoPtr card);
+    void cardInfoChanged(const CardInfoPtr &card);
     void cardDatabaseEnabledSetsChanged();
 };