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Database Models

This guide describes how to setup and update your modules database scheme. All database installation and update scripts will reside in your modules migration directory.


  • prefix your tables with the module id. e.g. example_foo
  • singular table names
  • use underscorce in fieldnames andattributes e.g. user_id

Initial Migration

Once you've a concept of your database scheme ready and want to start prototyping, you'll need to create an initial migration.

The following command executed in the protected directory will create a new migration into the protected/humhub/migrations folder:

php yii migrate/create mymodule_inital

which resembles the following grunt command executed within the root of your installation:

grunt migrate-create --name=mymodule_inital

Just copy the resulting migration from the protected/humhub/migrations folder into your module's migrations folder and add your schema setup. Please refer to the Yii Migration Guide for more information about how to use migrations.

Your table names should be prefixed with your unique module id like mymodule_entry.

Info: The humhub\components\Migration class provides some additional helper functions.

Tip: Since a Migration::safeUp() uses transactions you should consider splitting your migration files into multiple migrations.

Note: Only data manipulation queries can be rolled back in case a migration script fails.

Scheme Updates

In order to provide scheme updates for new versions, just follow the same steps as in the Initial Migration section.

You can manually execute new migrations by the following commands:

php yii migrate/up --includeModuleMigrations=1

or by grunt

grunt migrate-up

Missing migrations are also executed when accessing Administration -> Information -> Database.

Uninstall Migration

Your module should also provide an uninstall.php file. The uninstall migration is by default executed within your Module::disable() logic method and should look like:

use yii\db\Migration;

class uninstall extends Migration

public function up()

public function down()
echo "uninstall does not support migration down.\n";
return false;


Integrity Check

The integrity check is a command which validates and if necessary repairs the application database.

If you want to add own checking methods for your module to it, you can intercept the humhub\commands\IntegrityController::EVENT_ON_RUN event.

Example callback implementation:

public static function onIntegrityCheck($event)
$integrityController = $event->sender;
$integrityController->showTestHeadline("Polls Module - Answers (" . PollAnswer::find()->count() . " entries)");

foreach (PollAnswer::find()->joinWith('poll')->all() as $answer) {
if ($answer->poll === null) {
if ($integrityController->showFix("Deleting poll answer id " . $answer->id . " without existing poll!")) {


HumHub uses Yii's ActiveRecords as database access layer.