Is an _id created programatically unique?

Question

let's assume I do this:

$person = array(
   "_id" => new MongoId(),
   "name" => "Fabs",
   "city" => "Rome"
);

$people->save($person);

Can I be sure of the fact _id will be unique when $person is actually persisted? Because, after all, the id has been created "outside" of the DB (without the DB knowing) and there might well be that very id in the people collection already, no? I also understand it might be very unlikely but is it possible at all?

See http://stackoverflow.com/a/5694803/46375 This should hold true for any mongo driver. — whaley, Nov 23 '13 at 15:40

score 1 · Accepted Answer · answered Nov 23 '13 at 15:40

1

Of course it's possible, as it is with any other ID generation scheme that doesn't involve a central registry of IDs. The chance of it happening is so low, though, that i can safely assert that you'll never see it happen unless malice is involved.

answered Nov 23 '13 at 15:40

cHao

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I thought so too. Only wanted to nake sure. Thanks – nourdine Nov 23 '13 at 15:55

Is an _id created programatically unique?

1 Answers1