Mongo and aggregation framework

Le 3 juin 2015 à 19:32, [hidden email] a écrit :

Le 3 juin 2015 17:45, "Christophe Demarey" <[hidden email]> a écrit :
>
> Hello,
>
> I would like to use set operators defined in mongo but it looks like there is no support for the aggregation framework in the mongo driver.
> Does anyone has information about this?

Search the list as I posted an example before.

ok, I finally found your example :

mongo := Mongo default open.

db := mongo databaseNamed: 'somedb'.

aCommandDict := {  'distinct' -> 'somecollection'. 'key' -> 'XYZ'. 'query' -> nil } asDictionary.

reply := db command: aCommandDict.

(CollectionValidation on: reply) isOK.

distinct :=  reply at: #values.

There is no OO support in the driver for that.

So aggregate can be run as a command with the Mongo driver.

I checked the following code:

Mongo>>command: aDictionary database: aDatabase

| query |

query := MongoQuery new

database: aDatabase;

collection: (MongoMetaCollection name: '$cmd');

where: aDictionary;

yourself.

^self queryOne: query.

I do not understand why a MongoQuery is used there and why it is supposed to return only one element (queryOne)?

Thanks,

Christophe