Connecting a Calendar with a Database - flutter

Question

I am using the flutter package table_calendar and want to connect its events with a database.
For this use, I chose the sqflite package and flutter_bloc. There is a great tutorial on how to here: Database Storage in Flutter using Sqflite
The database uses a List datastructure but the calendar a Map< DateTime, List< dynamic>>.
I wrote a method that takes each event for a day found in the Database List and writes it in the Map in order to show everything in the UI. The regex are there since I save the date as a Text within the database and separate it with dots.
void shiftListToCustomEventsMap(List<Shift> shiftList) {
for (int i = 0; i < shiftList.length; i++) {
Shift shift = shiftList[i];
String helpStringForDate = shift.dateOfShiftString;
RegExp exp = new RegExp(r'(\d+)');
Iterable<RegExpMatch> matches = exp.allMatches(helpStringForDate);
int date = int.parse(matches.elementAt(0).group(0));
int month = int.parse(matches.elementAt(1).group(0));
int year = int.parse(matches.elementAt(2).group(0));
DateTime shiftDateTime = new DateTime.utc(year, month, date, 12);
if (customEvents[shiftDateTime] == null) {
// creating a new List and passing a widget
customEvents[shiftDateTime] = [_buildShiftContainer(shift: shift)];
} else {
List<dynamic> helpList = customEvents[shiftDateTime];
helpList.add(_buildShiftContainer(shift: shift));
}
}
}
Thus, I am using two data structures to handle the data, which is sub-optimal.
The problems start when I want to delete an event from the calendar.
Problem:
If I delete the second event of a day with the use of an index, the event gets deleted within the Map as I would like to but in the Database, it takes the second entity overall and deletes it.
Sub-Optimal Solution:
A way to solve it would be to create for each date a new Table in the Database but I am not sure that this is the best way to solve it.

Answer 1

I found the solution to my problem.
I now save the ID of the row found in the DB within my Shift object. I pass this object to a method to create a widget which I then use within a ListView.builder as a calendar event.
Now when trying to delete a calendar event, I retrieve the whole information of the widget. Within this widget, I have saved the ID position of the equivalent event within the database. Then I pass this id to delete the row from the database.
The following code is a part of the propose solution:
Shift deleteShift =
getParametersFromWidgetInTheList(
index: index);
// remove from database
DatabaseProvider.db
.delete(deleteShift.id)
.then((_) => BlocProvider.of<ShiftBloc>(
context)
.add(DeleteShift(deleteShift.id)));
// remove from customEvents Map
customEvents[_controller.selectedDay]
.removeAt(index);