I am using phpmyadmin from the official docker image. I am using the designer and I am wondering where the designer page is stored. I have read in this post that it is stored in phpmyadmin.pma__designer_coords table, but I don't have such "phpmyadmin" database.
Taking a look at the docker image file "/var/www/html/config.sample.inc.php" I have seen that "/* Storage database and tables */" section is fully commented by default.
So my questions are:
Thank you.
To use Designer you don't even need the extra tables (the phpMyAdmin Configuration Storage) configured; Designer will work but it won't save any layout changes you make. So it's possible (and seems likely in your case) that the tables aren't even in use.
When trying to automatically create the phpmyadmin database (following the zero configuration settings, usually initiated manually from the Operations tab), phpMyAdmin first tries to create the database 'phpmyadmin' and if that can't be created (such as a shared hosting server where the user only has access to one database) then it will try to create the tables in the current database. It doesn't sound like either of those are the case for you, though.
Taking a look at the docker image file "/var/www/html/config.sample.inc.php" I have seen that "/* Storage database and tables */" section is fully commented by default.
Correct, and this means a couple of things. First, config.sample.inc.php isn't actually parsed at all; you're expected to put your own config.inc.php (which you can copy directly or in part from the sample) there for it to load directly. Secondly, most configuration options shown are the default value, so even though it's commented out it's showing you what the default is anyway — so you don't need to explicitly set each table name, for instance, as long as the defaults are okay with you.
If I don't have phpmyadmin table, where is the designer page stored? I have looked into /var/www/html path but I didn't find anything.
I suspect what's happening is that the table doesn't exist and any layout changes you make aren't being saved.
how can I enable phpmyadmin database with docker configuration? Obviously I could override default config, but I don't want to deal with keeping it up-to-date with new releases.
In order to use the advanced features, I would create the 'phpmyadmin' database and populate it from the create_tables.sql script (available online or in the downloaded phpMyAdmin folder) as explained in the documentation. Once you create the tables once in your database server, you don't need to do it again. You'll probably need to specify the controluser and controlpass fields in the config.inc.php, but the rest of the Configuration Storage settings will probably be automatically detected from the default values. I usually define these anyway to avoid any ambiguity, but that's just my preference.
Create your own config.inc.php and the Docker image will copy it over, it only overrides values you define and uses defaults for all the others — so upgrading is usually effortless.