CODEWITHSUNDEEP
jsonmongodb
Mewtwo
Mewtwo

Reputation: 1311

How to split a JSON document in Mongo

I have documents of the following format:

{
"_id" : ObjectId("58af1ee3f78a9945bd9fc94d"),
"rounds" : {
    "matches" : {
        "team1" : {
            "name" : "Manchester United",
            "score1" : 1
        },
        "team2" : {
            "name" : "Tottenham Hotspur",
            "score2" : 0
        }
    }
}}

And I would like to get somenthing like this:

{
"_id" : ObjectId("SomeID"),
"rounds" : {
    "matches" : {
        "team1" : {
            "name" : "Manchester United",
            "score1" : 1
        }
    }
}

}

and

{
"_id" : ObjectId("SomeID"),
"rounds" : {
    "matches" : {
         "team2" : {
            "name" : "Tottenham Hotspur",
            "score2" : 0
        }
    }
}

}

I'm looking for something like unwind but unwind is applied only on arrays. How can I transform matches into an array of JSON? Any other ideas to achieved the desired result are welcome

Upvotes: 0

Views: 1712

Answers (1)

Jeff Justice
Jeff Justice

Reputation: 234

Maybe a mapreduce function, with just a map function? I don't really know your use case but if you are just returning one document at a time it might be best to do the refactoring after mongo returns the results.

db.somcollection.mapReduce(
function(){
    var matcharray = [];
    for (var match in this.rounds.matches) {
        if (this.rounds.matches.hasOwnProperty(match)) {
          matcharray.push({team:match,other:this.rounds.matches[match]});
        }
    }
    emit('matches',matcharray);

},
function(key,values){   
    return ( values );
},
{
    query:{"_id" : ObjectId("58af1ee3f78a9945bd9fc94d")},
    out: "somename"
}).find()

This results in the following, which is at least an array but not quite what you wanted using key/value pairs for everything.

{
"_id" : "matches",
"value" : [ 
    {
        "team" : "team1",
        "other" : {
            "name" : "Manchester United",
            "score1" : 1
        }
    }, 
    {
        "team" : "team2",
        "other" : {
            "name" : "Tottenham Hotspur",
            "score2" : 0
        }
    }
]
}

Upvotes: 1

Related Questions