ORM or SQL? A Better Way to Query in MySQL

I do not agree with some of the conclusions the speaker presented. That being said, his presentation was well prepared and he was a good speaker.

I completely disagree with not using foreign keys and joins. A well designed database should handle joins and foreign keys. Data integrity belongs in the database with validation in php. Without integrity you cannot tell customers that your data is accurate. If having scaling issues consider composite foreign keys in MySQL or, better yet, jump to Postgres. I don't agree with promoting bad practices.

I found the talk very informative. I learned a lot about effective use of SQL and related technologies. The speaker gave strong opinions and advocated certain approaches, but backed them up with detailed reasoning and examples.

His perspective on large scale systems seems consistent with what I've learned in my own systems background from Stanford graduate studies and work at places like Amazon.com.