}
+bool SqlEngine::deleteStaleEvents(int conferenceId, QSet<QString> eventIdsToKeep) {
+ QSqlQuery query(db);
+
+ // get all event IDs from conference
+ query.prepare("SELECT id FROM event WHERE xid_conference = ?");
+ query.bindValue(0, conferenceId);
+ bool success = query.exec();
+ emitSqlQueryError(query);
+ if (!success) return false;
+ QSet<QString> existingEventIds;
+ while (query.next()) existingEventIds.insert(query.value(0).toString());
+
+ // determine events that are not existing anymore
+ QSet<QString> eventIdsToRemove = existingEventIds.subtract(eventIdsToKeep);
+
+ // delete events including entries from referencing tables
+ QList<QString> tables = {"link", "event_room", "event_person"};
+ for(const QString& eventId: eventIdsToRemove) {
+ for(const QString& table: tables) {
+ query.prepare(QString("DELETE FROM %1 WHERE xid_conference = ? AND xid_event = ?").arg(table));
+ query.bindValue(0, conferenceId);
+ query.bindValue(1, eventId);
+ success &= query.exec();
+ emitSqlQueryError(query);
+ }
+ query.prepare("DELETE FROM event WHERE xid_conference = ? AND id = ?");
+ query.bindValue(0, conferenceId);
+ query.bindValue(1, eventId);
+ success &= query.exec();
+ emitSqlQueryError(query);
+ }
+
+ return success;
+}
+
+
void SqlEngine::emitSqlQueryError(const QSqlQuery &query) {
QSqlError error = query.lastError();
if (error.type() == QSqlError::NoError) return;