CODEWITHSUNDEEP
c#mongodb
Bob Horn
Bob Horn

Reputation: 34297

Is there a strongly-typed way to update a subdocument in MongoDB?

I have the need to update a subdocument in Mongo, and this is how I did it. This screenshot shows what my documents look like. And the code below it shows how I updated Geddy’s name and instrument.

enter image description here

Note: This approach was taken from this SO post:

var update = Update.Set("Members.$.Instrument", "Keyboards").Set("Members.$.LastName", "Leex");

var collection = MongoDbHelper.Db.GetCollection<Band>("Bands");
collection.Update(Query.And(Query.EQ("Name", "Rush"), Query.EQ("Members.FirstName", "Geddy")), update);

Is there another/better way to do this that makes use of strongly-typed properties instead of all of these string literals?

Upvotes: 1

Views: 1089

Answers (1)

Robert Stam
Robert Stam

Reputation: 12187

There is currently no support for writing queries or updates like this one (i.e. querying against individual subfields of arrays and using "$" in the update) using the typed builders.

The difficulty is coming up with expressions that compile without errors and yet express the desired intent correctly.

For example, the following might be a workable design, but using -1 as an index value is kind of hacky:

var query = Query.And(
    Query<Band>.EQ(b => b.Name == "Rush"),
    Query<Band>.EQ(b => b.Members[-1].FirstName == "Geddy"));
var update = Update<Band>
    .Set(b => b.Members[-1].Instrument, "Keyboards")
    .Set(b => b.Members[-1].LastName, "Leex");

Note: this is just a possible design for supporting "$" in typed builders. It is not actually implemented this way.

If you have any ideas for how a type safe version of this could be expressed you should create a JIRA ticket suggesting the feature.

Upvotes: 2

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