Ganerate unsaved random password and send them via email

I want to create a system using PHP, that can generate a number of random passwords respecting a given form (length:12, contains 4 numbers, 2 capital letters, 2 special characters and 4 small letters) something like that. The number of passwords generated correspond to a number of emails imported from a text file. When those passwords are generated, the system will automatically send them with some information details to the imported emails. But is it a logical way to not saving those passwords in a database and when the users try to connect with those passwords, the system will verify is it the correct form or not in order to allow the connection be successful? If this logic is possible, how can I verify if the user did enter the correct password ?