Clojurians Log v2

I don't think you should care so much about entity ids. And no, I don't think an entity can exist just with one datom, but I could be wrong, haven't checked it.

@hiskennyness : > Good points all. I am going to save all these for my Datomic tutorial before they scroll off the Clojurian history. This channel is archived to Zulip as https://clojurians.zulipchat.com/#narrow/stream/180378-slack-archive/topic/datomic which is a full, searchable history back to whenever the @zulip-mirror-bot was added to this channel.

(I figured this was a good opportunity to remind folks of the free, searchable archive of many channels here!)

For development we have a custom implementation of d/q-protocol which sends queries to tap>. it enables us to see what performance is of specific queries. we just wrap the existing connection in our system-map.

ah, cool, thanks!

is it possible to lock the usage of d/delete-database (on-prem)? it feels a little too easy to kill the entire db?

Yes, every transaction is written to durable storage. However, Cloud's use of DDB is opaque unless accessed from Datomic. So, I am not sure what insight you would get by reviewing the stream of writes other than "writes are occurring," which you could also see by monitoring with metrics in CloudWatch (txdatoms, txbatchbytes) or by reviewing the Cloud Dashboard (txes,Txbytes DDB usage, write count). I am interested in hearing more about what you're envisioning with DBstreams, maybe there is something here we should look at as a feature for Datomic. 🙂

@stuarthalloway bit off but which maven repository do you use/recommend for small corps//personal experimentation?

(intern 'datomic.api 'delete-database (fn [_] (println "Nope!")))

Haha! Yeah, outside of Francis's approach, we do not have a built in method for limiting api access. I have logged a feature request in this space and we will review options in this area.

Hello there! We, at Cognitect, are collecting feedback regarding the https://docs.datomic.com/cloud/dev-local.html getting started experience and entry points to dev-local. We'd love if you can communicate your feedback with us https://forum.datomic.com/t/requesting-feedback-on-dev-local-getting-started/1608/2 on the forum: https://forum.datomic.com/t/requesting-feedback-on-dev-local-getting-started/1608/2

@audiolabs I'm curious how quickly new accounts are approved on the forum (since I just signed up so I can read/reply to this).

@seancorfield I just approved yours. We're working to improve the forum experience in this regard.

Thanks -- I suspect you'll get quite a few new Datomic devs now dev-local is available 🙂

I tend to use an S3 bucket -- a maven repo is just a convention about files.

I was thinking of the tx-report-queue functionality in the peer library and how that might be possible in Cloud.

Hi folks, Does anyone know if there is a way to specify a unique identity that encompasses multiple attributes? For example, say I have entities of the following shape:

{:foo/a ...
 :foo/b ...
 :foo/c ...}

Sounds like you are looking for these: https://docs.datomic.com/cloud/schema/schema-reference.html#composite-tuples

That seems like it! Did I understand this correctly: underlying the tuple are multiple datoms? IOW a tuple is not a single datom, whose value is a tuple, but rather multiple datoms, joined logically into a tuple?

a composite-tuple (there are two other kinds of tuples--this is only composite tuples) is a denormalization that datomic keeps up to date for you.

it’s not magic, if that’s what you are thinking. In the index will be a datom corresponding to that assertion

if you define a composite :foo/a+b composed of :foo/a and :foo/b and you assert or retract :foo/a or :foo/b on an entity, an additional assertion will be added`[entity1 :foo/a+b [value-of-a value-of-b]]`

it’s fully materialized

Interesting

And can one of the elements of the tuple be an inverse relation?

For example, given the following entities:

{:bar/foos [{:foo/a ...
             :foo/b ...
             :foo/c ...}
            {:foo/a ...
             :foo/b ...
             :foo/c ...}]}

My goal is to make it such that the children of bar are all unique with respect to :foo/a

> And can one of the elements of the tuple be an inverse relation? no

you can either reverse the relation, or consider using db/ensure or a transaction function to enforce your invariant

Thanks -- I'll explore the other routes

note that an absent value for a component will write a nil into the composite value, which can be a problem if you’re using this to enforce uniqueness with rel types

because of retractEntity’s behavior

(you don’t have to use it, but it’s common to)

ah yes

noted, many thanks

If I have a list of tx-ids where I'll need to call d/as-of on each, are there any performance trade offs to consider? (e.g., should I sort the list desc/asc by tx before calling as-of)

dev-local utterly rocks the casbah.

I'm watching the feedback on the forum and the main theme so far (and I've seen it mentioned on Twitter etc too) is the process for getting dev-local means it's hard to use for CI and for multi-dev teams since you can't just depend on a version on Maven/Clojars. The fill-out-form-and-download-via-email-link is fine for me for experimenting but I wouldn't like it much if I was trying to set up repeatable builds across a team or in a CI system. Could Cognitect perhaps clarify who the target audience really is for dev-local @audiolabs?

It would be very surprising, imo, if the one of the objectives with dev-local was not to address the difficulty testing against Datomic Cloud during CI. Previously you'd need to figure out a complex docker setup with the Datomic socks proxy on CI and build your own db name prefix system. All of that is removed with dev-local.