Getting _id of inserted document

[mwa...@mz.com]

I'm enjoying using this library.

But I can't quite figure out how to get the '_id' of the document I just inserted.  E.g.

local db = assert(mongo.Connection.New())
assert(db:connect('localhost'))

local obj = {someKey = "someVal"}
local ans = db:insert('test.someDoc', obj)

print(inspect(ans)) -- 'true'
print(inspect(obj)) -- my original object, unmodified

If I were to do this in Node.js, I could use the optional callback function parameter to 'insert'.  

Or, I could look at my inserted obj and expect to see  '__id' element tacked on.

But it doesn't appear either mechanism works.

[Paco Zamora-Martínez]

Dear mwalsh,

Currently this feature is not implemented at luamongo. You should do a look up of your object to retrieve the Id.

Many thanks for your interest in luamongo. Regards

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Pako ZM :)

https://github.com/pakozm/

[mwa...@mz.com]

Sorry to be dense, but if I may follow-up, how would one look up the object if you don't know the _id? 

I could generate some kind of unique value and stick it in the document as part of the insert, then query on that, but then I have to make sure this value is truly unique.  Is some other way to look up the last inserted object?

[Paco Zamora-Martínez]

Yes, I usually add a new index to the mongo table and use it for my convenience. Another way is to generate values for _id before the insert operation. However, in some scenarios, the _id is not relevant at all, so you only need to write down data and retrieve it depending on the values, not their identity.

Regards