CODEWITHSUNDEEP
mongodbmongoosemongodb-queryaggregation-framework
vishalsingh
vishalsingh

Reputation: 43

How to merge document in mongodb based on an Id

Is there a way in mongoDb to merge documents based on id. For eg:

/*1*/{
"id" : "xxxxxx",
"pages" : {
    "name" : "Page50-50",
    "pageid" : "Page50-50",
    "icon" : "/images/cmstemplates/2column.png",
    "children" : []
 },
 "permissions" : [ 
    {
        "grpName" : "Admin",
        "grants" : [ 
            "View", 
            "Delete", 
            "Edit"
        ]
    }, 
    {
        "grpName" : "Users",
        "grants" : [ 
            "View"
        ]
    }
]
}
/*2*/
{
"id" : "xxxxxx",
"pages" : {
    "name" : "AboutUs",
    "pageid" : "AboutUs",
    "icon" : "/images/cmstemplates/1column.png",
    "children" : []
 },
 "permissions" : [ 
    {
        "grpName" : "Student",
        "grants" : [ 
            "View", 
            "Delete"
        ]
    }
]
}
Expected Output:
{
"id" : "xxxxxx",
"pages" : [{
    "name" : "Page50-50",
    "pageid" : "Page50-50",
    "icon" : "/images/2column.png",
    "children" : [],
    "permissions" : [ 
    {
        "grpName" : "Admin",
        "grants" : [ 
            "View", 
            "Delete", 
            "Edit"
        ]
    }, 
    {
        "grpName" : "Users",
        "grants" : [ 
            "View"
        ]
    }
]
},{
    "name" : "AboutUs",
    "pageid" : "AboutUs",
    "icon" : "/images/1column.png",
    "children" : [],
    "permissions" : [ 
    {
        "grpName" : "Student",
        "grants" : [ 
            "View", 
            "Delete"
        ]
    }
]
}]
}

The permissions params in the expected output should come inside pages, and pages should group into an array. I used $group and was able to group the pages, but i am not able to figure out how can i add permissions param inside pages. I am using mongodb 3.2.

Thanks.

Upvotes: 1

Views: 1874

Answers (1)

Rahul Sharma
Rahul Sharma

Reputation: 10111

Use $group

db.getCollection('Collection').aggregate([{
    $group: {
        "_id": "$_id",
        "pages": {
            $push: "$pages"
        }
    }
}])

Upvotes: 2

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