Querying by Comparing to ObjectId

Question

I have val maxId = new ObjectId(...) and I want to query something like this: collection.find("_id" $lte maxId). This is a compilation failure since ObjectId doesn't include the appropriate trait ValidDateOrNumericType. How to properly query objects by comparing their ID?

In the Mongo shell this seems to be possible:

> db.test.find({"_id": {$lte: ObjectId("4e825d2f84ae30e970bc0f95")}})
{ "_id" : ObjectId("4e82540684ae236af6e72177")}
{ "_id" : ObjectId("4e825baa84aea840b82e0278")}
...
>

Also with the Java driver it works:

query.put("_id", new BasicDBObject("$lte", new ObjectId("4e825d2f84ae30e970bc0f95")))

Is this doable with Casbah?

score 0 · Answer 1 · edited May 23 '17 at 10:34

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You can implement the comparison 'operator' as a method. To use it your ObjectId has to be on the left side of the comparison.

You can use the "pimp my library" to provide a implicit conversion to something that contains the comparison. (see this question How does ‘1 * BigInt(1)’ work and how can I do the same?)

Or you can implement a trait which offers the desired functionality.

edited May 23 '17 at 10:34

Community

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answered Oct 05 '11 at 12:42

Jens Schauder

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I don't understand how this would solve the issue which seems to be more on the MongoDB side of things? – hleinone Oct 05 '11 at 13:41
Sorry I thought we were talking about a Scala problem. – Jens Schauder Oct 05 '11 at 14:05
Well, I guess it's somewhat specific to the Scala driver for MongoDB. – hleinone Oct 05 '11 at 14:26

score 0 · Accepted Answer · answered Feb 12 '12 at 19:45

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With Casbah this can not be done, since ObjectId does not convert to ValidDateOrNumericType. I ended up using the Java API:

collection.find(new QueryBuilder().put("_id").lessThanEquals(maxId).get())

answered Feb 12 '12 at 19:45

hleinone

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Querying by Comparing to ObjectId

2 Answers2