Method refreshPreview

src/frontend/datasources/ImportSQLDatabaseWidget.cpp:294–399

}

void ImportSQLDatabaseWidget::refreshPreview() {
	if (!ui.lwTables->currentItem()) {
		setInvalid();
		return;
	}

	WAIT_CURSOR;
	ui.twPreview->clear();
	bool customQuery = (ui.cbImportFrom->currentIndex() != 0);

	// save the last used custom query
	if (customQuery) {
		KConfig config(m_configPath, KConfig::SimpleConfig);
		KConfigGroup group = config.group(ui.cbConnection->currentText());
		group.writeEntry("Query", ui.teQuery->toPlainText());
	}

	// execute the current query (select on a table or a custom query)
	const QString& query = currentQuery(true);
	if (query.isEmpty()) {
		RESET_CURSOR;
		setInvalid();
		return;
	}

	QSqlQuery q;
	if (!q.prepare(query)) {
		RESET_CURSOR;
		setInvalid();
		return;
	}
	q.setForwardOnly(true);
	q.exec();
	if (!q.isActive() || !q.next()) { // check if query was successful and got to first record
		RESET_CURSOR;
		if (!q.lastError().databaseText().isEmpty())
			Q_EMIT error(i18n("Failed to execute the query for the preview") + QStringLiteral(" \n") + q.lastError().databaseText());
		else
			Q_EMIT error(i18n("Failed to execute the query for the preview"));

		setInvalid();
		return;
	}

	// resize the table to the number of columns (=number of fields in the result set)
	m_cols = q.record().count();
	ui.twPreview->setColumnCount(m_cols);

	// determine the names and the data type (column modes) of the table columns.
	// check whether we have numerical data only by checking the data types of the first record.
	m_columnNames.clear();
	m_columnModes.clear();
	bool numeric = true;
	// TODO: use general setting for decimal separator?
	QLocale::Language lang;
	if (ui.cbDecimalSeparator->currentIndex() == 0)
		lang = QLocale::Language::C;
	else