Query (find many) documents from multiple collections with the same document structure (MongoDB & PHP)

Question

I use MongoDB PHP v1.3 and in my MongoDB I have multiple collections:

// COLLECTION NAMES:
- user_1_list_1
- user_1_list_2
- user_1_list_3
...
- user_1_list_55

All these collections have the same document-structure:

{
   first_name
   last_name
   phone
}

How can I query the documents from all of these collections at the same time? In the documentation, it is explained how to query (find many) documents from one collection: https://docs.mongodb.com/php-library/v1.3/tutorial/crud/#find-many-documents.

For example, in my case, it would look something like this:

$collection_name = "user_1_list_1";
$collection = $this->db->{$collection_name};

$query = []; 

$cursor = $collection->find(
    $query,
    [
        'limit' => 10,
        'skip'  => 0,
        'sort'  => ['first_name' => 1],
    ]
);

... but this will find documents only from one collection (in this case, only from the collection with name "user_1_list_1").

How to find documents from all of these collections (user_1_list_1, user_1_list_2, user_1_list_3 ... ) (that have the same structure), not just from one specific? Is this possible at all? If yes, how would you do that?

Answer 1

MongoDB is not a relation database and there is no good solution for your case.

1. You can get your collections and loop over it (but it’s a not good solution).
2. You can change your database structure and use one collection with embedded data