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[11:36:53] <rebab> How do I find datas under 5 characters?

[11:42:53] <Derick> strings with less than 5 characters?

[11:44:51] <Derick> You can use the Aggregation Framework with $strLenBytes, and then match against that: https://docs.mongodb.com/v3.4/reference/operator/aggregation/strLenBytes/#single-byte-and-multibyte-character-set

[11:56:41] <rebab> I figure it out using regex ^.{0,150}$

[11:57:28] <Derick> my approach is likely faster

[11:58:41] <rebab> Okay I'll study on it. Is there a way to remove same datas? I have a lot of data in my database. Some of them are the same. I want to remove them.

[11:59:01] <Derick> I don't think there is a database specific way

[11:59:08] <Derick> you'll have to do that in a script or program

[16:03:08] <wfq> Hi all

[16:03:54] <wfq> how can I force that a one to one relationship from document to document ensure that the referenced document exists in the database at saving time. Do I need to do a read first?

[16:04:51] <wfq> I don't want to use embedded documents

[16:11:18] <wfq> or where can I find specific information about constraints in one-to-one relationships please?

[16:11:39] <Derick> there are no foreign keys in MongoDB

[16:16:46] <wfq> Derick, yes. I keep forgetting this. The only way is by firing a reading query and at that mongodb is very fast, I guess the argument would be

[16:17:06] <wfq> Thanks

[16:18:09] <Derick> you should really store these things in one document though

[16:18:29] <wfq> Derick, sorry I am not sure what you mean

[16:18:51] <Derick> there is no point in having a 1:1 relation between documents. Just make it one document.

[16:19:06] <wfq> My problem is that I have a hierarchy where documents are related with each other

[16:19:19] <Derick> that's not 1:1 one then, but rather 1:n ?

[16:19:42] <wfq> Derick, not. A document will only be related to a parent one

[16:19:58] <Derick> but a parent can have multiple children...

[16:20:58] <wfq> I know where you are coming from and suggest me to use a ListField of ReferenceFields instead

[16:21:23] <Derick> these are not MongoDB words...

[16:21:36] <Derick> perhaps they're mongoose words?

[16:21:49] <wfq> Derick, sure... I keep mixing mongodb with RDBMS and MongoEngine with mongodb

[16:21:51] <wfq> sorry about that

[16:22:12] <wfq> I highly regret to have used it and not go with pymongo directly

[16:22:19] <wfq> they are two learning curves

[16:22:22] <Derick> yes.

[16:22:40] <Derick> It's really best to start with the "native" drivers when learning MongoDB

[16:22:59] <wfq> Derick, absolutely agree with that.

[16:23:27] <Derick> what would be *best* in your case, is to do the read, and the write(s) in a transaction

[16:23:46] <Derick> but not sure whether MongoEngine supports that

[16:25:20] <wfq> Derick, here we go, the two learning curves again. I am on the verge to tear it down altogether

[16:25:30] <wfq> Derick, thanks. I have now sufficient info

[16:26:13] <wfq> by the way transactions is just something a sort of recent in MOngo, right?

[16:26:22] <Derick> yes, MongoDB 4.0

[16:26:51] <wfq> beautiful though: https://www.mongodb.com/transactions

[16:28:41] <Derick> i hadn't seen that yet

[16:29:05] <wfq> It seems very intuitive

[16:29:27] <Derick> there are some gotchas with the API, but we're working on that for the drivers

[16:50:58] <wfq> Derick, thanks. In my next personal project I'll work with pymongo directly. I like sitting on the driving seat :)

[16:53:15] <Derick> :-)

[22:11:01] <binarylegit> Hello, We are using MongoDB 3.4, We have an external service attempting to connect directly to a secondary, but it appears that it must first auth to the primary in order to run any queries. Is that documented anywhere? or am I misunderstanding something?