What function does the save() method perform in Active Record Yii2 and what is it used for?

The save() method in Active Record Yii2 is used to save the current state of the model object to the database. If the object is new (i.e., does not exist in the database), save() performs an insert operation; if the object already exists, it updates the corresponding record.

This method is used for convenient and intuitive interaction with the database through objects, without the need to write SQL queries manually.

Example usage:

$model = new User();
$model->username = 'ivan';
$model->email = 'ivan@example.com';
$model->save(); // inserts a new record into the user table

// Updating an existing record
$model = User::findOne(1);
$model->email = 'newemail@example.com';
$model->save(); // updates the record with id=1