Question

I have a capped collection without an _id index and I don’t need the _id at all,
but the PHP mongo driver always adds an _id on insert.

It is possible to suppress the automatic generation of an _id with the mongo shell

How can I supress the _id on insert with PHP?

Answer 1

You cannot get rid of _id , but you can overwrite it.
So you can insert 1 column data into _id field.

eg.

$myCollection->insert(array("_id" => 2000, "data" => "someData));