Adminer - Single-File Database Manager

Been using both Adminer and phpMyAdmin since 2018. Adminer is basically phpMyAdmin's lighter, faster cousin that supports more databases. Here's what you actually need to know.

The Reality: It's Just Better

Adminer is one PHP file, around 500KB. phpMyAdmin is 13MB+ of files. Both manage databases, but Adminer doesn't make you wait 5 seconds for every page load.

On my dev box, Adminer loads table views fast enough that I don't want to punch the screen. phpMyAdmin makes me consider switching to command line for everything. Three other devs I know switched after getting tired of waiting 30 seconds for every goddamn page load. Way more responsive when you're debugging production at 2am and already hate everything.

The official docs have performance comparisons, and most MySQL GUI reviews rank it well.

Database Support That Actually Matters

Works with the databases you're probably using:

Out of the box:

• MySQL/MariaDB (obviously)
• PostgreSQL
• SQLite (great for dev/testing)
• SQL Server (if you're stuck with Windows)
• Oracle (if you hate yourself and love suffering)

With plugins:

• MongoDB (though you should probably use Compass)
• Elasticsearch (basic support)

Most web apps use MySQL or PostgreSQL anyway. Adminer handles both without the "MySQL-only" bullshit that makes phpMyAdmin completely fucking useless for PostgreSQL projects.

Security That Actually Works

Adminer isn't perfect - patched it twice last year for XSS issues. But phpMyAdmin's security record is Swiss cheese with new CVEs every few months. Adminer at least has decent defaults:

Rate limiting on login attempts (stops brute force). No blank passwords allowed (forces authentication). Smaller codebase = fewer attack vectors. Updates that don't break everything.

CVE database shows a few vulnerabilities including SSRF and XSS issues. Keep it updated and follow security practices.

Still, don't be an idiot - put it behind HTTP auth or firewall it. Any web-based database tool is a security risk if left wide open.

What Sucks About It

Let's be honest about the downsides:

Interface is different from phpMyAdmin - takes getting used to. Fewer themes and plugins. Some features buried in menus. Documentation gaps mean I still Google basic stuff. MySQL Workbench beats it for complex query analysis.

Can't just drop it on any server. Had one shared host where it wouldn't work - their custom PHP restrictions blocked mysqli_connect() by default. Took 3 support tickets to figure that out.

For simple database management though? Adminer wins. Upload file, connect, get work done. No dependency hell or config nightmares.

The Easy Way

Download adminer.php, stick it on your web server. Done.

wget https://www.adminer.org/latest.php
mv latest.php adminer.php

Upload to your web root, navigate to yoursite.com/adminer.php. If you see a login form, you won.

What Can Go Wrong

Because it's never that simple:

1. White Screen of Death

• Problem: PHP extensions missing
• Fix: Enable mysqli, pdo_mysql, or whatever database extension you need
• Check: php -m | grep mysql or look at phpinfo()

2. 403 Forbidden Errors

• Problem: File permissions wrong
• Fix: chmod 644 adminer.php (or 755 if your host is weird)
• Apache: Make sure .htaccess isn't blocking PHP files

3. Can't Connect to Database

• Problem: Database server unreachable or credentials wrong
• Common: localhost vs 127.0.0.1 vs actual hostname
• Docker: Use container name as hostname, not localhost
• Error: "Connection refused" = database server down or wrong port
• MySQL 8.0+: Default auth plugin changed to caching_sha2_password - older Adminer versions fail silently with just a blank screen. Spent 3 fucking hours debugging this last month on a client's staging server. Error message? What error message? Just blank login screen, no hint that MySQL changed their shit.
• PostgreSQL: Make sure pg_hba.conf allows connections from your web server IP. Error: FATAL: no pg_hba.conf entry for host - learned this the hard way on a Docker setup where containers couldn't talk to each other.
• Cloud databases: Azure/AWS need SSL enabled. AWS RDS throws SSL connection error without it. Took me an afternoon to figure out the first time because the error message sucked.

4. Session Errors

• Problem: PHP sessions not working
• Fix: Make sure /tmp is writable or configure session path
• Check: session.save_path in PHP config

Docker (If You're Into That)

docker run --link your_db:db -p 8080:8080 adminer

Works great until:

• Your database container has a random name (use actual container name)
• Network isn't shared (use --network flag)
• Database server binds to localhost only (fix database config)

Security (Don't Get Fired)

HTTP Auth (Recommended):

## .htaccess
AuthType Basic
AuthName "Database Access"
AuthUserFile /path/to/.htpasswd
Require valid-user

DigitalOcean has a guide for HTTP auth setup.

Nginx:

location /adminer.php {
    auth_basic "Database Access";
    auth_basic_user_file /etc/nginx/.htpasswd;
}

Stack Overflow thread has Nginx examples and reverse proxy setup. Ubuntu guide here.

Other Options:

• Put behind VPN/firewall
• Use HTTPS (credentials get sniffed otherwise)
• Delete when not needed (it's just one file)
• Don't leave on production servers (seriously, don't)

Common Fuck-ups I've Seen

1. Leaving Adminer on production - Bots find it, database gets owned. Seen this shit twice. One client lost their entire customer database because some genius left adminer.php in web root with no auth. Took them 3 days to restore from backups.
2. Using root database credentials - One compromise = full database access. Create a read-only user. Learned this when junior dev connected with root and accidentally ran DROP DATABASE on staging.
3. No HTTPS - Credentials sent in plain text. Saw staging server get compromised after login got sniffed on public wifi.
4. Weak HTTP auth - "admin/admin" gets brute forced in hours. Security team found our test instance and sent an unhappy email.
5. Wrong file permissions - Either doesn't work or world-readable. Error: Permission denied - spent 2 hours on this with weird cPanel permissions.
6. PHP memory limits - Large exports die silently. Error: Fatal error: Allowed memory size exhausted - killed production for 30 minutes trying to export a 2GB table. No warning, just dies halfway through.
7. max_input_vars too low - Large SQL imports fail halfway through with no error. Took 4 hours to figure out why import kept failing at the same point every time.
8. Subdirectory with weird Apache configs - CSS breaks, looks like 1995. Client thought their site got hacked because it looked broken.
9. Shared hosting with disable_functions - Half the features don't work because exec() is disabled. Took an afternoon to figure out why exports failed. Host didn't mention this shit anywhere in their docs.
10. Version compatibility hell - Adminer 4.8.1 works with PHP 7.4 but chokes on PHP 8.1 with weird warnings. Version 4.7.x completely breaks with MySQL 8.0. Always test on your exact environment first.

Real Performance Settings

Don't bother with "optimization" - it's one PHP file. Just make sure:

memory_limit = 128M        # For large imports
max_execution_time = 300   # For slow queries
upload_max_filesize = 32M  # For SQL dumps
post_max_size = 32M        # Ditto

Themes That Don't Suck

Download adminer.css and put it next to adminer.php:

• Dracula - Dark theme that's easy on the eyes
• Material Design - If you like Google's design
• Default dark - Built-in dark mode

Official plugin system has more customization. Customization guide for advanced themes and server-specific switching. Stack Overflow thread for theme installation.

Time Estimates (What Actually Happens)

• Download and upload: 2 minutes unless your internet sucks
• First connection: Sometimes works immediately, sometimes you're debugging MySQL auth bullshit for half a day
• Debugging connection issues: Plan for an afternoon. Host issues can take a week of support ticket hell.
• Setting up security: 15 minutes if you know Apache, otherwise learn .htaccess the hard way

Still have questions? The FAQ below covers the most common issues developers run into, from database size limits to hosting compatibility.