与已经在数据库中的条目相比较，找出RSS提要中的新数据。然后在db中输入新的条目。如何?

Let's say I have a database, and an RSS feed. I have to find out what is the new data from an RSS feed, that isn't already in the database. How would you go about approaching this problem?Let's say I have a database, and an RSS feed. I