I'm building a feed aggregator. I have a lot of blog addresses and I want to save all the posts in a database. I'm using Simplepie to get feeds and then with php I'm inserting them into a database. Simplepie's API is very large, and I don't know which parts of the post I should save. So far I'm saving:
I want to know what other things I should save in the database. I don't know the whole API and it's pretty long.
You could just take a reverse engineer approach.
Pick a handful of feeds that you already have and view the url source to see what tags are in the feed. After checking a few you should be able to determine what most feeds contain and decide how to setup your db.
For example this is a feed url:
feeds.feedburner.com/webresourcesdepot?format=xml
You can put that in your browser, view source, and then find a section with feed content and determine what tags they have.
You could also go through the RSS specs and take a look at all the valid options for a valid RSS feed.