Create MongoDB ObjectID from date in the past using PHP driver

Question

I have to import a lot of data into MongoDB from MySQL and I\'d like to use the timestamp from the ObjectID instead of storing it in a separate key/value (as it is in the ex

Answer 1

If you are using the MongoId just for comparison, for example, selecting all records within a date range, you don't need a fully valid id. So you could simply do:

$id = new \MongoId(dechex($timestamp) . str_repeat("0", 16));

Just be sure to never insert this id and just use it for $gte/$gt/$lt/$lte queries.

edit

My bad, the above snippet would work with dates before about 1979 as dechex($timestamp) doesn't always return 8 characters, so a better snippet would be:

$id = new \MongoId(sprintf("%08x%016x", $timestamp, 0));