Many levels of relationship

[piotrek1231]

Hi, I have table Timetable which contains list of Activity (One To Many). Activity contains list of Place (One To Many).

Below sample code which adding data:

            Timetable plan = new Timetable();
            plan.Id = "idKey";
            plan.Version = "1.0";
            plan.Activities = new List<Activity>();


            Activity act1 = new Activity() { Name = "Activity name 1", Id = 200, Places = new List<Place>() };
            act1.Places.Add(new Place { Id = 444, Name = "Place - activity 1" });


            Activity act2 = new Activity() { Name = "Activity name 2", Id = 201, Places = new List<Place>() };
            act2.Places.Add(new Place { Id = 443, Name = "Place - activity 2" });

            plan.Activities.Add(act1);
            plan.Activities.Add(act2);

Next, I add this to db and read:

            _sqlLiteConnection.InsertWithChildren(timetable);
            var results = _sqlLiteConnection.GetAllWithChildren<Timetable>(); 

In results I have Timetable object witch 2 Activity, but in Activity list of Place is still null.

Thanks

[Guillermo Gutiérrez]

You are not inserting the activities into the database, and therefore they are not being assigned when fetching the timetable. Take a look at the Cascade operations section of the documentation where it's explained how to insert a full tree of objects in the database, and then read to memory again.

[Guillermo Gutiérrez]

Closed because it's not an issue. Please consider using StackOverflow with the sqlite-net-extensions tag to ask questions and this tool to report issues.

[piotrek1231]

I think that I did it in right way:

Piece of Timetable:

        private List<Activity> _activities;
        [JsonProperty(PropertyName = "activities")]
        [Indexed]
        [OneToMany(CascadeOperations = CascadeOperation.All)]
        public List<Activity> Activities
        {
            get { return _activities; }
            set { _activities = value; RaisePropertyChanged("Activities"); }
        }

Piece of Activity:

        [ForeignKey(typeof(Timetable))]
        public string TimetableId { get; set; }

        [ManyToOne]      
        public Timetable Timetable { get; set; }


        private List<Place> _places;
        [JsonProperty(PropertyName = "category")]
        [OneToMany(CascadeOperations = CascadeOperation.All)]
        public List<Place> Places
        {
            get { return _places; }
            set { _places = value; RaisePropertyChanged("Places"); }
        }

Piece of Place:

        [ForeignKey(typeof(Activity))]
        public string ActivityId { get; set; }

        [ManyToOne]
        public Activity Activity { get; set; }

[Guillermo Gutiérrez]

In that case you're only missing the recursive parameter of the insert method:

_sqlLiteConnection.InsertWithChildren(timetable, recursive: true);

[piotrek1231]

Thanks for reply. Now, I have something like this:

_sqlLiteConnection.InsertWithChildren(timetable, recursive: true);

but Places are still null.

[Guillermo Gutiérrez]

You also need the recursive parameter when reading the objects from database...

var results = _sqlLiteConnection.GetAllWithChildren<Timetable>(recursive: true);