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Questions tagged [datomic]

Datomic is a database of flexible, time-based facts, supporting queries and joins, with elastic scalability, and ACID transactions.

From the datomic website:

Datomic is a database of flexible, time-based facts, supporting queries and joins, with elastic scalability, and ACID transactions.

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430 questions
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Basic logging in Clojure web service not appearing on console

I am following this tutorial to set up application logging in my Clojure web app, which I am going to be using for some Datomic experimentation. The tutorial suggests that all I have to do is add Clojure's clojure.tools.logging library to my…
Owen S.
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lein install datomic peer library on mac

I cannot get leiningen to download the datomic-pro peer library. I have the following setup: ~/.lein/credentials.clj.gpg {#"my\.datomic\.com" {:username "..." :password "..."}} And the project (defproject datomic-example…
shaft
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Access control in Datomic

When writing an application based on Datomic and Clojure, it seems the peers have unrestricted access to the data. How do I build a multi-user system where user A cannot access data that is private to user B? I know I can write the queries in…
Jason
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"No reader function" error using Datomic in Light Table

When I eval this code in lighttable: (ns app.core (:require [datomic.api :refer [q] :as d] :reload-all)) (defn add-person [conn id] (d/transact conn [{:db/id #db/id[:db.part/user -1000001] :person/id id}])) I…
ajsie
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qualified relationships in datomic

In a relational DB, I could have a table Person and a table Hobby. Every person can have zero, one or more hobbies, and I also want to record, say, the priority of those hobbies for every person. I could create a relationship table with the 2…
SuperHorst
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Clojure RuntimeException - No reader function for tag db/id

What is happening when I get this error in Clojure? java.lang.RuntimeException: No reader function for tag db/id
Zefira
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In which position does Datomic lies in the CAP Triangle?

Recently I heard that Datomic as a modern database, can be excellent at data modeling and scalability. But I know little of it. Does the Datomic database follows the CAP Theorem? If so, in which position does it lies in the CAP Triangle?
cmal
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How to update/overwrite a ref attribute with cardinality many in datomic?

Let’s say I have a schema that includes an attribute :x/value, where :x/value is a component, is a ref, and has cardinality many. The schema also has an id for x :x/id. Now let’s say I say I transact the following: (d/transact conn [{:x/id "1234"…
fraxture
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Datomic error message

I'm getting this when I'm calling transact: datomic.impl.Exceptions$IllegalArgumentExceptionInfo: :db.error/not-a-data-function Not a data function: 71 data: {:db/error :db.error/not-a-data-function} …
Kevin
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How to setup Datomic with Heroku Postgresql?

I have trouble setting up Datomic with Heroku Postgres. First of all I have this successfully installed [com.datomic/datomic-pro "0.9.5206" :exclusions [joda-time]] My sql-transactor.properties file looks like…
ma2s
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Is datalog more efficient than SQL for column oriented databases?

Both Cascalog and Datomic have chosen to use Datalog (over SQL) as their query engine. Dave Thomas made the claim: Datalog is better than SQL for large queries in small amounts of space. My question is: Is datalog more efficient than SQL for…
hawkeye
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Has entities in Datomic metadata like creation and update time?

I want to know e.g. when an entity was created or updated. Should I create an attribute like :created-at and :update-at or Datomic has theses attributes by default? Or any manner to find out when an entity was created or updated?
Felipe
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How to deal with a variable in a library that needs to be set outside of it?

I'm using Datomic in several projects and it's time to move all the common code to a small utilities library. One challenge is to deal with a shared database uri, on which most operations depend, but must be set by the project using the library. I…
konr
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Nesting structures With Datomic

Using Datomic, I'm trying to think of how can I nest a list within a list? An example Clojure data structure would be something (see fig.1). I know that Datomic has the notion of references (ex. in fig.2). But those just look like scalar types, not…
Nutritioustim
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how would one write a datomic query that takes the entire set into account

Is it possible to write these sort of queries in datomic? find the name of the oldest kid find the person with the lowest body-mass index (weight / height)
zcaudate
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