diff --git a/src/core/databasefactory.cpp b/src/core/databasefactory.cpp
index 6771e38a5..aa87c5d85 100644
--- a/src/core/databasefactory.cpp
+++ b/src/core/databasefactory.cpp
@@ -72,6 +72,9 @@ QSqlDatabase DatabaseFactory::initialize(const QString &connection_name) {
            qPrintable(database.lastError().text()));
   }
   else {
+    // TODO: smazat QSQLDatabase::exec() všude
+    // a nahradit jej funkcí QSQLquery::exec()
+
     database.exec("PRAGMA encoding = \"UTF-8\"");
     database.exec("PRAGMA synchronous = OFF");
     database.exec("PRAGMA journal_mode = MEMORY");
diff --git a/src/core/feedsmodelcategory.h b/src/core/feedsmodelcategory.h
index f2e0116f7..9d6459112 100644
--- a/src/core/feedsmodelcategory.h
+++ b/src/core/feedsmodelcategory.h
@@ -23,6 +23,9 @@ class FeedsModelCategory : public FeedsModelRootItem {
     explicit FeedsModelCategory(FeedsModelRootItem *parent_item = NULL);
     virtual ~FeedsModelCategory();
 
+    // Counts of messages.
+    // NOTE: Counts of messages in categories include
+    // counts of messages from all children.
     int countOfAllMessages() const;
     int countOfUnreadMessages() const;
 
diff --git a/src/core/feedsmodelfeed.h b/src/core/feedsmodelfeed.h
index b7d9c7417..c92bac769 100644
--- a/src/core/feedsmodelfeed.h
+++ b/src/core/feedsmodelfeed.h
@@ -24,6 +24,8 @@ class FeedsModelFeed : public FeedsModelRootItem {
     int childCount() const;
 
     // Getters/setters for count of messages.
+    // NOTE: For feeds, counts are stored internally
+    // and can be updated from the database.
     int countOfAllMessages() const;
     int countOfUnreadMessages() const;
 
diff --git a/src/core/feedsmodelstandardcategory.h b/src/core/feedsmodelstandardcategory.h
index 63d4df3aa..c3a9fbadf 100644
--- a/src/core/feedsmodelstandardcategory.h
+++ b/src/core/feedsmodelstandardcategory.h
@@ -18,11 +18,13 @@ class FeedsModelStandardCategory : public FeedsModelCategory {
     explicit FeedsModelStandardCategory(FeedsModelRootItem *parent_item = NULL);
     virtual ~FeedsModelStandardCategory();
 
+    // Returns the actual data representation of standard category.
     QVariant data(int column, int role) const;
 
     // Performs update on all children of this category.
     void update();
 
+    // Loads particular "standard category" from given sql record.
     static FeedsModelStandardCategory *loadFromRecord(const QSqlRecord &record);
 };