How do I join 2 collections using the Phalcon framework?

Question

I have 2 collections which I would like to join together using the Phalcon PHP framework.

I would know how to do this in MySQL, however I am wondering if it is possible when using MongoDB, a non-relational database.

Assuming my collections are:

Robots

_id
name
age

Robot Parts

_id
robot_id
name
quantity

This is a Phalcon specific question, hence I don't think it is a duplicate. Thanks — Shailen Varsani, Jul 13 '17 at 10:09

score 3 · Accepted Answer · answered Jul 13 '17 at 09:49

Hey Shailen & welcome to StackOverflow :)

Even though MongoDB is not a relational database, it does allow joining of collections by using the aggregation framework which comes as part of MongoDB since version 3.2.

You should be able to achieve this with something like:

$results = RobotCollection::aggregate([
    [
        '$lookup' => [
            'from' => 'robot_parts',
            'localField' => '_id',
            'foreignField' => 'robot_id',
            'as' => 'parts'
        ]
    ]
]);

In this example, the robot document will have a new field added to it 'parts' (or whatever you name it in the 'as' field of the $lookup). The parts will be matched where robot_parts.robot_id = robots._id

You can learn more about the $lookup pipeline step here: https://docs.mongodb.com/manual/reference/operator/aggregation/lookup/#pipe._S_lookup

Hi Armon, Thanks for your prompt reply to my question. This has worked perfectly! Thanks so much for your help. — Shailen Varsani, Jul 13 '17 at 10:02

How do I join 2 collections using the Phalcon framework?

1 Answers1