how to delete event from calendar with event SQL

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package com.example.test1;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.widget.CalendarView;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {

    private mySQLiteDBHandler dbHandler;
    private EditText editText;
    private CalendarView calendarView;
    private String selectedDate;
    private SQLiteDatabase sqLiteDatabase;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        editText = findViewById(R.id.editText);
        calendarView = findViewById(R.id.calendarView);

        calendarView.setOnDateChangeListener(new CalendarView.OnDateChangeListener() {
            @Override
            public void onSelectedDayChange(@NonNull CalendarView view, int year, int month, int dayOfMonth) {
                selectedDate = Integer.toString(year) + Integer.toString(month) + Integer.toString(dayOfMonth);
                ReadDatabase(view);
            }
        });
        try {
            dbHandler = new mySQLiteDBHandler(this, "CalendarDatabase", null, 1);
            sqLiteDatabase = dbHandler.getWritableDatabase();
            sqLiteDatabase.execSQL("CREATE TABLE EventCalendar(Date TEXT, Event TEXT)");
        }
        catch (Exception e){
            e.printStackTrace();
        }
    }
    public void InsertDatabase (View view){
        ContentValues contentValues = new ContentValues();
        contentValues.put("Date",selectedDate);
        contentValues.put("Event",editText.getText().toString());
        sqLiteDatabase.insert("EventCalendar",null,contentValues);
    }
    public void ReadDatabase(View view){
        String query = "Select Event from EventCalendar where Date =" +selectedDate;
        try {
            Cursor cursor = sqLiteDatabase.rawQuery(query,null);
            cursor.moveToFirst();
            editText.setText(cursor.getString(0));
        }
        catch (Exception e){
            e.printStackTrace();
            editText.setText("");
        }
    }
}

package com.example.test1;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

import androidx.annotation.Nullable;

public class mySQLiteDBHandler extends SQLiteOpenHelper {
    public mySQLiteDBHandler(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory, int version) {
        super(context, name, factory, version);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {

    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    }
}

im making a simple calendar with event but i realize that after type something on certain day i couldn't erase it nor change it. it will stay whatever it was saved as the first time.
And also im planning to make the save button open a new activity to insert detail and save into a note in  another activity. How do i do that?