What are Relational Databases?

Good Morning from my Robotics Lab! This is Shadow_8472 and today I am targeting Nextcloud for major milestone completion. Let’s get started.

Previously on my Nextcloud saga, I finally managed to run a pod with both Nextcloud and MariaDB in their own containers and get them to talk. The words they exchanged were along the lines of “Access Denied.” I also have a script to add a temporary third container for database command line access.

My next immediate job is learning enough MySQL to diagnose Nextcloud’s refusal to create an admin account. I found a few commands to try and learned that the database I expected to be there on container creation didn’t appear to be. Container logs didn’t report any errors. I need some more background research, even if that’s the only thing I do this week.

Most important things first: what is the relationship between MariaDB and MySQL? I’ve been treating the former as if it were an implementation or distribution of the later – like the difference between Debian and Linux. But according to MariaDB’s site, they’re a fork that avoids “vendor-lock” while maintaining protocol compatibility with MySQL [1]. So MySQL help should still work for MariaDB on a “close enough” basis, sort of like how Debian solutions may still work for Ubuntu systems. When available: use a matching guide.

Contrary to what I said in my closing words last time I handled Nextcloud, commands being written in all caps is only convention – the software is usually a lot more forgiving. SELECT equals sELeCT which equals select and SelEct as well as the other 60 possible combinations.

MariaDB is what is called a “relational database.” Fancy phrase to me, but here goes an explanation. Data is information. Information can be organized into tables for later retrieval. Zoom out one level, and now tables with information themselves become data that interacts with information in other tables. MariaDB can track these “relations.”

Takeaway

Needless to say, relational databases gets messy fast. Considering how my database is meant to be locked up tight within a pod on a server that blocks direct access, a containerized webUI I can expose will do nicely. MariaDB’s website has a lengthy list of graphical clients, but only phpMyAdmin showed up as having this feature when I used “find on page” [2]. Importantly, it also shows up in Docker.io as a Docker Official Image, which I can run on Podman.

Final Question

As of posting, I’m planning on spending a week or few each for learning phpMyAdmin and refining my MariaDB understanding. Otherwise, if someone can answer what my problem is that Nextcloud isn’t finding the expected database. The following is a command from my pod creation script.

podman create \
        --pod NextcloudRedLaptop \
        --name MariaDBContainer \
        -v MariaDBVolume:/var/lib/mysql:Z \
        -e MARIADB_ROOT_PASSWORD="<gibberish1>" \
        -e MARIADB_DATABASE=NextcloudDB \
        -e MARIADB_USER=nextcloudDbUser \
        -e MARIADB_PASSWORD="Gibberish2" \
        --restart on-failure \
        docker.io/library/mariadb:latest

And here is what I think is the important output from MariaDB:

MariaDB [(none)]> SHOW DATABASES;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mysql              |
| performance_schema |
| sys                |
+--------------------+
4 rows in set (0.010 sec)

If I understand what I need correctly, I should have had one show up titled “NextcloudDB” on container creation.

And so, my final question is this: Why doesn’t it work? Am I even looking in the right spot?

If I oversimplified or got something wrong about relational databases, be sure to tell me all about it in the comments!

Works Cited

[1] MariaDB, “MariaDB vs. MySQL The difference between choice and vendor lock-in,” MariaDB, [Online]. Available: https://mariadb.com/database-topics/mariadb-vs-mysql/. [Accessed Sept. 18, 2023].

[2] MariaDB, “Graphical and Enhanced Clients,” MariaDB, [Online]. Available: https://mariadb.com/kb/en/graphical-and-enhanced-clients/. [Accessed Sept. 18, 2023].