存储要在数据库中执行的操作，还是从代码中决定？

Question

I've got a website in which I want to send some followup emails to customers a certain number of days after they bought something. I now wonder how to do that. I think there are two options:

1. Create a table in my DB in which I store the emails which I plan to send. So I simply store the customer email address and the date on which I want to send it. I then simply run a cron every day and send the emails that need to be sent and set the status in the table to "sent". The advantage of this method is that I know which emails need to be sent. The disadvantage is that I'm less flexible; it's not easy to change the number of days after which I send the emails because they are stored in the DB.
2. I can also do it from the code by simply running a cron that gets the list of customers who bought something an x number of days ago, send them the email, and only then store the fact that I sent them an email in the database. The advantage of this method is that I'm more flexible. If I want to send out the emails later I can simply define that in the code (or some var). The disadvantage is that I don't have a list of emails which are going to be sent (although I don't really know what that would be useful for).

My question is actually; what is best practice in this case? How do most websites handle this and why?

Answer 1

I would choose method 2.

The disadvantage is not really a disavantage. Supposing you got an "order" table, you can get the list of mail to send just making a query quite similar the one used by your cron.

But it is a personal choice. I don't know which method is normally used.