CODEWITHSUNDEEP
mongodb
Pelit Mamani
Pelit Mamani

Reputation: 2381

Retrieving the newly-generated _id when inserting through Shell

This might be trivial, but when running 'insert' from Mongodb shell, I can't seem to retrieve the newly-generated _id :

db.coll.insert({someField:"someValue"});
var theId=??? /* How to get the _id of my newly inserted object? */

I know how to retrieve it through language specific drivers (java, node.js) but not from the Shell. So far I eliminated the following :

var x=db.coll.insert(...)
print(x);
// Doesn't work: x is undefined

var doc={...}
db.coll.insert(doc);
print(doc._id)
// Doesn't work, prints undefined

Thank you

Upvotes: 1

Views: 97

Answers (1)

gilby
gilby

Reputation: 232

Try this:

var doc={...} db.coll.save(doc); print(doc._id)

Note that db.collection.save() will update a document if it finds a match by _id. In your case, it will do an insert.

Honestly, I'm not quite sure why db.collection.insert() doesn't populate _id in your in-memory document...

Upvotes: 2

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