MongoDB using $returnKey to get Field Name and value -

i have run trouble mongodb. trying value of field, field name not known me , use retrieved value check existence of different document in collection. aware of pattern of value field might containing.

let me explain, have following document structure:

db.blogs_data.find({"_id.r":"http://blog_post_url/authors"}).pretty(); {     "_id" : {         "r" : "http://blog_post_url/authors"     },     "author:_1" : {         "u" : "people:c2ce29e7"     },         "author:_2" : {         "u" : "organisations:0b2a962a-8d1c"     },     "rdf:type" : {         "u" : "rdf:seq"     } } 

here author:_2 can : author:_n (numeric). now, details of each sequence in above decument stored separate document, :

db.blogs_data.find({"_id.r":"people:c2ce29e7"}).pretty(); {     "_id" : {         "r" : "people:c2ce29e7"     },     "rdf:type" : {         "u" : "foaf:person"     },     "foaf:name" : {         "l" : "mccabe, catherine"     } }   db.blogs_data.find({"_id.r":"organisations:0b2a962a-8d1c"}).pretty(); {     "_id" : {         "r" : "organisations:0b2a962a-8d1c"     },     "rdf:type" : {         "u" : "foaf:organisations"     },     "foaf:name" : {         "l" : "abc publications"     } } 

now, need value of each sequence of /authors, author value pattern : "organisations*", , use value sequence check author details documents, if exists or not. i've checked mongodb, , have $returnkey, says returns index key or keys, http://docs.mongodb.org/v2.2/reference/operator/returnkey/#op._s_returnkey but, document seems incomplete , bit confusing me too, : " if $returnkey set true , query not use index perform read operation, returned documents not contain fields."

well, don't know exact key value is, , value inside it. i've checked mongodb names of keys in collection however, returns unique keys in collection.

it seems me mongo query won't want here, , i've write js script this. there facing same or similar problem? in case of js, should considered starting point?

regards,

i've solved problem :

using regex mongo documents id.r ends /authors, , looping through each author:n inside authors document , use value of author_:n check existence of actual author document.

ravish