Mongodb Find Is Not Working With The Objectid

Here is my code and I'm getting null value for the doc. But in the findOne({'webpageid':docs[i]._id} instead of docs[i]._id if I pass the webpageid it works. And I verified docs ha

Solution 1:

Your webpageids are strings while the _ids that you are searching with are ObjectIds. Your find does not match any results because there are no documents in the results table which have ObjectId values for the "webpageid" element.

There are two solutions as I see it.

1. You could store ObjectIds instead of strings for the webpageid element in the results collection. The implementation of this is of course based on how those documents get into the collection.

2. You could create a string variable from the returned ObjectId within the loop to compare instead. For example,

   ...
   for(var i = 0; i < docs.length; i++) {
       var docId = docs[i]._id.toString(); // create a string
       db.get('results').findOne({'webpageid':docId}, function(err, doc)
       ...
   

If you go with the second option, you may need to look into why there is a leading quote at the beginning of the webpageid value for the second document in the results collection.

"webpageid" : "\"54960a916ecb16dc3c4880e8"

Lastly, I don't know much about your requirements, but you may want to rethink MongoDB as a solution. It appears that you are creating something like a JOIN which is something MongoDB is not designed to handle very well.