Unable to see which functions are available from DB object

I’m looking at code from previous developers, having never used Yii (but having used other frameworks like Zend Framework, CakePHP, and Symfony), and my PHPStorm is unable to find contextual function suggestions, either due to it not understanding Yii or not being able to figure out which class the object is using, which could just be me missing some sort of config or the previous developers coding things in an odd way.

Yii::$app->db_api->createCommand("DELETE FROM {$deleteTable} WHERE {$column} = :deleteId")->bindParam(':deleteId', $crudObject->deleteId, \PDO::PARAM_INT)->execute();

When I hover over $app and Cmd+click (to trace to definition), it goes to api_yii2/vendor/yiisoft/yii2/BaseYii.php (I don’t know how the viisoft files were installed) var public static $app;, which says it’s for \yii\console\Application|\yii\web\Application the application instance.

Now, I just want to see quickly what’s available to the db_api object… which PHPStorm seems unable to find. Is there some way to add a code comment or maybe change something in how db_api is instantiated that can make it easy for me to see a function/var list when I need to, rather than continually checking the class file?