Releases, release groups, duplicates

MusicBrainz Development
, ,
1

I’m still trying to figure out exactly what the differences are between releases and release groups. Right now, I’m running into situations where there are two separate releases that appear to be the same. Same barcode, same catalog number, same label, same everything. The release ids are 2759862 and 286398. What makes these two separate entries in the database?

2

A release group is just when there are different releases under the same grouping. For example, Release by artist vs. Release (deluxe version) by artist. Variant of the same release. Both releases in same release group. Not sure what those IDs are as MB IDs don’t look like that. Maybe link to them? Duplicates do occur and sometimes can be merged. Maybe they are the same. However, keep in mind, minor things can make up different releases. Check relationships for things like manufacturing plants, copyrights, etc. Could be minor artwork differences, etc. But if you are sure everything is the same you can always put in a merge edit. Unfortunately, it’s not uncommon for editors to re-add duplicate releases. Please link to the 2 releases you have questions about, that’ll help answer your question better.

4 Likes
3

The release IDs will link to the proper releases when inserted into an URL (forwarding to here and here). The releases in your example have different release events and also marked differences in cover art.

I take it that you have found the documentation about release groups?

3 Likes
4

Please edit your post and paste 2 actual release URL.

5

Yes, I have. Different release events? What is a release event? There’s no mention of that on either the release or release group documentation pages? Where is release event stored?

6

Wow, I never knew there were any IDs other than the long strings, lol. Doh.

2 Likes
7

The release event is the date and country of release. These are likely different because one is US and one is Canada. The Canada release is not likely “printed in the US”, but I can’t find a Canada release with this barcode on Discogs to see. Or it could be just a US release imported into Canada. Not sure.

2 Likes
8

biocv gave the links in his comment. The number I gave is the id field in the release table. The guid is what appears in the URL of each page.

1 Like
9

Oh, okay. I was looking through the data tables for something with the terms release and event.

Can I also ask, where does format, under release information, come from? Because The Wall in these two cases, says 2 x CD. But there’s nothing in the medium_format table called 2 x CD. And no other table has a field called format, other than medium.

10

Ah OK, you’re not working on the website, you’re working on the database!
I’ll update this topic category, then. :slight_smile:

3 Likes
11

A CD as popular as The Wall will be pressed for many years with artwork changing causing different Releases. (Look at the rear covers of those two you link - CAN , USA) It will release in multiple countries and then editions pressed at different factories. Different Releases. Something pressed in such huge numbers world wide can end up with many editions with small variations.

Look at the Release Group of The Wall and it may start to make a little more sense. It is a grouping of the release variations.

3 Likes
12

Yes. Sorry. That goes under development, and I just did MB in general?

1 Like
13

From admin/sql/CreateTables.sql:

CREATE TABLE medium ( -- replicate (verbose)
    id                  SERIAL,
    release             INTEGER NOT NULL, -- references release.id   
    position            INTEGER NOT NULL,
    format              INTEGER, -- references medium_format.id
    ...
);

CREATE TABLE medium_format ( -- replicate   
    id                  SERIAL,
    name                VARCHAR(100) NOT NULL,                       
    ...
);

If you look at t/sql/initial.sql, you can see some example statements to insert different formats:

INSERT INTO medium_format VALUES (1, 'CD', NULL, 0, 1982, true, NULL, '9712d52a-4509-3d4b-a1a2-67c88c643e31');
INSERT INTO medium_format VALUES (2, 'DVD', NULL, 4, 1995, false, NULL, '2875c583-4580-3a90-b723-ba1b39921e23');
...

I’m guessing that lib/MusicBrainz/Server/Entity/Util/MediumFormat.pm is the code that’s responsible for producing the multiple-media string that you saw.

3 Likes