modify item in database table : I have this sqlite database :

      private static final String TAG = "DatabaseHelper";
    
    private static final String TABLE_NAME = "people_table";
    private static final String COL1 = "_id";
    private static final String COL2 = "Hour";
    private static final String COL3 = "Minutes";
    private static final String COL4 = "On_Off";


How cand I modify the value of the On_Off fom 1 -> 0 and  0 -> 1 Pseudocod:


      public void OnAlarm()
    {
        SQLiteDatabase db = this.getWritableDatabase();
        db.execSQL( "UPDATE " + TABLE_NAME + " SET " + COL4 + "=1 WHERE ");
    
    }
    public void OffAlarm()
    {
        SQLiteDatabase db = this.getWritableDatabase();
        db.execSQL( "UPDATE " + TABLE_NAME + " SET " + COL4 + "=0 WHERE ");
    
    }