CODEWITHSUNDEEP
c#mongodb
Nathan Ridley
Nathan Ridley

Reputation: 34396

MongoDB and C# - How do I query for all documents matching a list of given ID values?

I have set up my database so that the ID property of my class is the ID of the document:

BsonClassMap.RegisterClassMap<TestClass>(cm =>
{
    cm.AutoMap();
    cm.SetIdMember(cm.GetMemberMap(c => c.ID));
});

To query for a specific document, I can successfully use:

collection.FindOneById(123);

However if I try the equivalent as a query:

collection.FindOne(Query.EQ("ID", 123));

No results are returned.

How do I include the document ID as part of the query and/or how do I query for a list of documents matching a given set of IDs? Do I have to literally query them one by one?

EDIT To clarify, I'm not talking about an internal MongoDB-assigned object ID, I'm talking about the ID assigned by the user as the unique key/id identifying that document for later retrieval.

Upvotes: 1

Views: 1366

Answers (1)

Christopher Currens
Christopher Currens

Reputation: 30695

If you're talking about the internal ID that MongoDB uses, it's specifically a BsonObjectId and needs to be queried as one. Also, the ID field for MongoDB documents is lowercase and starts with an underscore: _id Code like this should work:

collection.FindOne(Query.EQ("_id", ObjectId.Parse("4dad901291c2949e7a5b6aa8")));

Upvotes: 2

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