来自多维数组的mongodb pull元素

Question

Hi i have the following array and i want to pull the array with productId 100343

Array(
    [_id] => MongoId Object
        (
            [$id] => 5388a02c8ead0ebf048b4569
        )

    [cartId] => 14ce496ac194d5d8ee8d0cd11bd3ef5a
    [products] => Array
        (
            [100343] => Array
                (
                    [productId] => 100343
                    [quantity] => 13
                    [name] => a
                )

            [100344] => Array
                (
                    [productId] => 100344
                    [quantity] => 3
                    [name] => ab
                )

            [100345] => Array
                (
                [productId] => 100345
                    [quantity] => 1
                    [name] => abc
                )

        )

)

I've tried like this but it doesn't work

$c->update(
    $aQuery, 
    array(
        '$pull' => array('products'=>array('productId'=>'100343'))
    )
);

Answer 1

That is not an array. Arrays in MongoDB are different in concept to what PHP calls an array, so the structure you have there is the same as this JSON representation:

{
    "products": {
        "100343": {
            "productId": 100343,
            "quantity": 13,
            "name": "a"
        },
        "100344": {
            "productId": 100344,
            "quantity": 3,
            "name": "ab"
        },
        "100345": {
            "productId": 100345,
            "quantity": 1,
            "name": "abc"
        }
    }
}

That sort of structure is just a use of sub-documents and is not an array in the sense as used by MongoDB. To remove the entry as you want with this structure you use the $unset operator.

$c->update(
    $aQuery, 
    array(
        '$unset' => array('products.productId.100343' => "")
    )
);

But really you need to change your data, so to serialize a proper array for MongoDB you need to structure code like this:

$data = array(
    "products" => array(
         array(
             "productId" => 100343,
             "quantity" => 13,
             "name" => "a"
         ),
         array(
             "productId" => 100344,
             "quantity" => 3,
             "name" => "ab"
         ),
         array(
             "productId" => 100345,
             "quantity" => 1,
             "name" => "abc"
         )
     )
 );

That produces a JSON structure that looks like this:

{
    "products":[
        {
            "productId":100343,
            "quantity":13,
            "name":"a"
        },
        {
            "productId":100344,
            "quantity":3,
            "name":"ab"
        },
        {
            "productId":100345,
            "quantity":1,
            "name":"abc"
        }
    ]
}

That is what MongoDB calls an array, so now you can use the $pull operator correctly:

$c->update(
    $aQuery, 
    array(
        '$pull' => array( 'products.productId' => 100343 )
    )
);