MongoDB Dataset

The MongoDB Dataset is a read only dataset based on a MongoDB collection. It is meant to be used as a bridge between MLDB and MongoDB by allowing MLDB SQL queries to run over a MongoDB collection.

Caveat

• mongodb.dataset will not work on collections having key "_id" that are not ObjectIDs. See MongoDB ObjectID
• Some less popular BSON types are not supported. See BSON Types -- Regular Expression -- DBPointer -- JavaScript -- JavaScript (with scope) -- Min key -- Max key

Configuration

A new dataset of type mongodb.dataset named <id> can be created as follows:

mldb.put("/v1/datasets/"+<id>, {
    "type": "mongodb.dataset",
    "params": {
        "uriConnectionScheme": <string>,
        "collection": <string>
    }
})

with the following key-value definitions for params:

Example

For this example, we will use a MongoDB database populated with data provided by the book MongoDB In Action. The zipped json file is available at http://mng.bz/dOpd.

Here we create a dataset named mongodb_zips_bridge.

mldb.put('/v1/datasets/mongodb_zips_bridge', {
    'type' : 'mongodb.dataset',
    'params' : {
        'connectionScheme': 'mongodb://somehost.mldb.ai:11712/zips',
        'collection': 'zips'
    }
})

We can directly query it.

mldb.query("SELECT * NAMED zip FROM mongodb_zips_bridge ORDER BY pop DESC LIMIT 5")