How to search a string in inner array using mongodb?

Question

How to search value in multidimensional array, for example I want to search example keyword in the following data in mongodb I used to fetch all data from command

>db.info.find()

{
    "_id" : ObjectId("4f74737cc3a51043d26f4b90"),
    "id" : "12345",
    "info" : [
            {
                    "sno" : 1,
                    "name" : "ABC",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 2,
                    "name" : "XYZ",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 3,
                    "name" : "XYZ",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 4,
                    "name" : "ABC",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 5,
                    "name" : "Rohan",
                    "email" : "[email protected]"
            }
    ]
}

Now, to find data having example I used command

>db.info.find({"info.email":"example"}) and it gives

{
    "_id" : ObjectId("4f74737cc3a51043d26f4b90"),
    "id" : "12345",
    "info" : [
            {
                    "sno" : 1,
                    "name" : "ABC",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 2,
                    "name" : "XYZ",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 3,
                    "name" : "XYZ",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 4,
                    "name" : "ABC",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 5,
                    "name" : "Rohan",
                    "email" : "[email protected]"
            }
    ]
}

But I want only 3 out of 5 sub rows like

{
    "_id" : ObjectId("4f74737cc3a51043d26f4b90"),
    "id" : "12345",
    "info" : [
            {
                    "sno" : 1,
                    "name" : "ABC",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 2,
                    "name" : "XYZ",
                    "email" : "[email protected]"
            },
            {
                    "sno" : 5,
                    "name" : "Rohan",
                    "email" : "[email protected]"
            }
    ]
}

Derick · Accepted Answer · 2012-04-06 10:33:18Z

2

Rohan, MongoDB always returns the whole document that you are searching on. You can't just make it return the array elements in which your keyword was found. If you want to do that, then you need to make sure all all embedded documents in the "info" field are in their own collection. And that might mean that you need to link them back to the original document in your "info" collection. Perhaps something like:

{
    "sno" : 1,
    "name" : "ABC",
    "email" : "[email protected]"
    "info_id" : "12345",
},

Alternatively, you can of course do post-processing in PHP to obtain only the rows that you want.

answered Apr 6, 2012 at 10:33

Derick

36.9k7 gold badges82 silver badges104 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Rohan Kumar Over a year ago

Derick can we say it is a drawback of mongodb?

Derick Over a year ago

It's something that MongoDB wasn't designed for. You need to be aware though that your map reduce solution will have totally different performance characteristics and might end up being a lot worse when you're doing this concurrently. I would still advice it to do in the client.

frietkot · Accepted Answer · 2012-04-06 10:23:32Z

1

Perhaps this is a good idea? http://php.net/manual/en/class.mongoregex.php

answered Apr 6, 2012 at 10:23

frietkot

91112 silver badges31 bronze badges

1 Comment

Rohan Kumar Over a year ago

It will give whole document not the searched inner array data.

Rohan Kumar · Accepted Answer · 2012-04-27 05:49:19Z

I tried Map Reduce Function and it works on this type of problems the code is something like that:

Write a map function

  map=function () 
  {
      filter = [];
      this.info.forEach(function (s) {if (/example/.test(s.email)) {filter.push(s);}});
      emit(this._id, {info:filter});
  }

Write a reduce function

  reduce=function(key, values) { return values;}

MapReduce Function

  res=db.info.mapReduce(map,reduce,{out:{inline:1}})

And The Output look likes:

"results" : [
    {
            "_id" : ObjectId("4f9a2de0ea4a65c3ab85a9d3"),
            "value" : {
                    "info" : [
                            {
                                    "sno" : 1,
                                    "name" : "ABC",
                                    "email" : "[email protected]"
                            },
                            {
                                    "sno" : 2,
                                    "name" : "XYZ",
                                    "email" : "[email protected]"
                            },
                            {
                                    "sno" : 5,
                                    "name" : "Rohan",
                                    "email" : "[email protected]"
                            }
                    ]
            }
    }
    ],
    "timeMillis" : 1,
    "counts" : {
            "input" : 3,
            "emit" : 3,
            "reduce" : 0,
            "output" : 3
    },
    "ok" : 1,

Now you can find your search data from

   printjson(res.results)

wuct · Accepted Answer · 2013-11-07 07:17:03Z

0

Did you try $ (projection)?

db.info.find({"info.email":"example"}, {"info.email.$":1})

document

answered Nov 7, 2013 at 7:17

wuct

10.5k2 gold badges22 silver badges22 bronze badges

Collectives™ on Stack Overflow

How to search a string in inner array using mongodb?

4 Answers 4

2 Comments

1 Comment

Comments

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

2 Comments

1 Comment

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related