Update table based on currentYear value from dropdown (external data) - google-app-maker

Question

I have a table displaying vacation requests from employees. Right now I'm displaying requests from all years in that table with the "onAttach" event. I want to implement a dropdown with a binding to the "year" column in my external sql data. so whenever I select a year out of that dropdown, I want the table to update only showing requests from that specific year in the table. How do I implement it?
the onAttach function loadHolidayTable() of the table leads to this client function
function loadHolidayTable() {
app.datasources.HolidayModel.load({
failure: function (error) {
displayTimedSnackbar('Unable to load holidays table: ' + error);
}
});
}
My Server Script in the datasource "HolidayModel"
return calculateHolidayModel(query);
leads to this server function:
function calculateHolidayModel(query) {
var queryStr = '';
var currentYear = null; --> to be replaced by dropdown value
if (currentYear === null || currentYear == 'undefined') {
queryStr = 'SELECT * FROM Holidays WHERE employeeID = ' + "'" + empID + "'";
}
else {
queryStr = 'SELECT * FROM Holidays WHERE employeeID = ' + "'" + empID + "'" + ' AND year = ' + "'" + currentYear + "'";
}
console.log(queryStr);
//var dayRecords = [];
var holidayRecords = [];
var connection = getJDBCConnection_();
var statement = connection.prepareStatement(queryStr);
try {
var results = statement.executeQuery();
while(results.next()) {
var holidayRecord = app.models.HolidayModel.newRecord();
holidayRecord.ID = results.getInt(2);
holidayRecord.From = new Date(results.getString(3));
holidayRecord.To = new Date(results.getString(4));
holidayRecord.Status = results.getString(5);
holidayRecords.push(holidayRecord);
console.log(results.getInt(2));
}
results.close();
statement.close();
} catch (err) {
console.log(err);
}
return holidayRecords;
}
currentYear should be replaced by the value from the dropdown.
any suggestions are welcome!