How to import Mongodb ObjectId from CSV file using mongoimport?

Question

I am struggling to import Mongodb's ObjectId from a CSV file using mongoimport:

I tried every combination and escape method I could think of but can't import ObjectId correctly from CSV.

First I tried importing exactly what I get exported from MongoDB to CSV. I am using MongoDB 2.2.1.

I just created two collections and referenced one document's _id in another document:

use yourdb
db.createCollection("student")
db.createCollection("class")
db.student.insert({"name":"Peter"})
db.student.find() returns { "_id" : ObjectId("5143af326d44e1ceb372121d"), "name" : "Peter" }
db.class.insert({"student_id": ObjectId("5143af326d44e1ceb372121d"),"name":"II-4"})

Then I used mongoexport command in shell:

mongoexport -h localhost:3002 -d yourdb -c classes --csv -f student_id,name > export.txt

Resulting CSV looks like this:

student_id,name
ObjectID(5143af326d44e1ceb372121d),"II-4"

Then I imported the resulting CSV using:

mongoimport -h localhost:3002 -d yourdb -c class --type csv --file export.txt --headerline

Quering class collection now returns:

db.class.find()
{ "_id" : ObjectId("5143afc66d44e1ceb372121e"), "student_id" :   ObjectId("5143af326d44e1ceb372121d"), "name" : "II-4" }
{ "_id" : ObjectId("5143b44788df173ba096550e"), "student_id" : "ObjectID(5143af326d44e1ceb372121d)", "name" : "II-4" }

As you can notice student_id field in the second document is actually a string and not MongoDB ObjectId.

I am wrong on something or Mongo can't import it's own exported CSV??

Answer 1

For anyone with this issue who's trying to insert ObjectIds from JSON - it very much IS possible with a bit of modification to the existing data.

Replace:

{ "_id" : ObjectId("5143afc66d44e1ceb372121e"),
  "student_id" : ObjectId("5143af326d44e1ceb372121d"),
  "name" : "II-4" }

With:

{ "_id" : {"$oid":"5143afc66d44e1ceb372121e"},
  "student_id" : {"$oid":"5143af326d44e1ceb372121d"},
  "name" : "II-4" }

Just use a regular expression to replace the ObjectId wrap.