How can I update a inner property using the 10gen c# driver? - mongodb

Question

I have this structure:
public class User
{
public ObjectId Id { get; set; }
public Location Location { get; set; }
public DateTime LastAround {get;set;}
}
public class Location
{
public double Latitude { get; set; }
public double Longitude { get; set; }
}
I've tried a few things but I want to update User's Location and when they were last around.
Tried this:
userHelper.Collection.Update(
Query.EQ("_id", userId),
Update.SetWrapped<Location>("Location", new Location { Latitude = latitude, Longitude = longitude }).Set("LastAround", DateTime.UtcNow));
and this:
userHelper.Collection.Update(
Query.EQ("_id", userId),
Update.Set("Location.Latitude", latitude)
.Set("Location.Longitude", longitude)
.Set("LastAround", DateTime.UtcNow));
Nothing worked...how can I do this?
Update 4/17:
userHelper.Collection.Update(
Query.EQ("_id", new ObjectId(userId)),
Update
.SetWrapped<Location>("Location", new Location { Longitude = longitude, Latitude = latitude })
.Set("LastAround", DateTime.UtcNow)
);
The lng and lat value orders seem to be very important when doing queries on them. I was doing a geonear query and getting an strange out of bounds error. If you update in the wrong order it will put lats first and then you get the error.

Answer 1

Both of your original Update statements should work. I wrote a small sample program to demonstrate.
After executing this Insert statement:
var userId = ObjectId.GenerateNewId();
var user = new User
{
Id = userId,
Location = new Location { Latitude = 1.0, Longitude = 2.0 },
LastAround = new DateTime(2012, 4, 14, 0, 0, 0, DateTimeKind.Utc)
};
collection.Insert(user);
The document looks like this in the mongo shell:
> db.test.find()
{ "_id" : ObjectId("4f8c5d33e447ad34b8c7ac84"), "Location" : { "Latitude" : 1, "Longitude" : 2 }, "LastAround" : ISODate("2012-04-14T00:00:00Z") }
>
After executing the first form of the Update statement:
collection.Update(
Query.EQ("_id", userId),
Update
.SetWrapped<Location>("Location", new Location { Latitude = 3.0, Longitude = 4.0 })
.Set("LastAround", new DateTime(2012, 4, 15, 0, 0, 0, DateTimeKind.Utc)));
the document looks like this:
> db.test.find()
{ "_id" : ObjectId("4f8c5d33e447ad34b8c7ac84"), "Location" : { "Latitude" : 3, "Longitude" : 4 }, "LastAround" : ISODate("2012-04-15T00:00:00Z") }
>
And after executing the second form of the Update statement:
collection.Update(
Query.EQ("_id", userId),
Update
.Set("Location.Latitude", 5.0)
.Set("Location.Longitude", 6.0)
.Set("LastAround", new DateTime(2012, 4, 16, 0, 0, 0, DateTimeKind.Utc)));
the document looks like this:
> db.test.find()
{ "_id" : ObjectId("4f8c5d33e447ad34b8c7ac84"), "Location" : { "Latitude" : 5, "Longitude" : 6 }, "LastAround" : ISODate("2012-04-16T00:00:00Z") }
>
So the two forms of the Update statement are working.
The full program is here:
http://www.pastie.org/3799469

Answer 2

Both of your alternatives look ok.
Are you sure that your userId variable had the correct value? It could be that the Update is not finding a matching document to update.

Answer 3

What I ended up doing:
var userHelper = new MongoHelper<User>();
ObjectId id = new ObjectId(userId);
var user = userHelper.Collection.FindAll().Where(u => u.Id == id).Single();
user.LastAround = DateTime.UtcNow;
user.Location = new Location { Longitude = longitude, Latitude = latitude };
userHelper.Collection.Save(user);
which works. Not sure why the other way wouldn't. I suppose this is more "SQL" like although might not have the best performance. :(