duancong7573 2017-07-13 09:44
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如何使用Phalcon框架加入2个集合? [重复]

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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
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  • doudongdang4483 2017-07-13 09:49
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    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

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
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