Datomic MusicBrainz sample database
Datomic is a database of flexible, time-based facts, supporting queries and joins with elastic scalability, and ACID transactions.
MusicBrainz is an open music encyclopedia that collects music metadata and makes it available to the public. This sample project uses the MusicBrainz dataset, but is in no way affiliated with or sponsored by MusicBrainz.
The MusicBrainz dataset makes a great example database for learning, evaluating, or testing Datomic. To create this sample database, we have exported the MusicBrainz distribution database as EDN data files, imported that data into Datomic according to the Schema described below, and backed up that database.
Included in this project are:
- Instructions for downloading and restoring the Datomic backup to your local transactor
- Datomic Datalog rules to be composed together to create interesting queries
- Some sample queries as a starting point
Getting Started
Getting Datomic
Follow the directs in https://docs.datomic.com/pro/releases.html to download Datomic Pro and unzip it somewhere convenient.
Start the transactor:
cd datomic-pro-$VERSION
bin/transactor config/samples/dev-transactor-template.properties
Getting the Data
Next download the subset of the mbrainz database covering the period 1968-1973 (which the Datomic team has scientifically determined as being the most important period in the history of recorded music):
wget https://s3.amazonaws.com/mbrainz/datomic-mbrainz-1968-1973-backup-2017-07-20.tar -O mbrainz.tar
tar -xvf mbrainz.tar
From the datomic-pro-$VERSION directory, restore the backup:
# prints progress -- ~1,000 segments in restore
bin/datomic restore-db file://path/to/backup/mbrainz-1968-1973 datomic:dev://localhost:4334/mbrainz-1968-1973
Getting the Code
Clone this git repo somewhere convenient:
git clone [email protected]:Datomic/mbrainz-sample.git
cd mbrainz-sample
Running the examples
From Java
Fire up your favorite IDE, and configure it to use both the included pom.xml and the following Java options when running:
-Xmx2g -server
Then visit the queries page.
From Clojure
Start up a Clojure REPL:
# from the root of this mbrainz-sample repo
lein repl
Then connect to the database and run the queries.
Schema
Here is a diagram of the relationships:
For information about the schema in general, or about individual entities and their attributes, please see the schema page in the wiki, or the EDN schema itself.
Example Queries and Rules
Please see the queries page in the wiki.
Thanks
We would like to thank the MusicBrainz project for defining and compiling a great dataset, and for making it freely available.
Contributing
This tutorial is developed internally by Cognitect. Issues can be filed using Github Issues. We do not accept pull request or patches.
License
Copyright © Metadata Partners, LLC. All rights reserved.
Distributed under the Eclipse Public License, the same as Clojure.