There has been a lot of talk lately about schemaless models touted by NoSQL groups and how PostgreSQL fits into this New world order.
Is PostgreSQL Object-Relational? Is it Multi-Model. We tend to think of PostgreSQL as type liberal and it's liberalness gets more liberal with each new release. PostgreSQL is fundamentally relational, but has little bias about what data types define each column of related tables. One of PostgreSQL great strengths is the ease with which different types can coexist in the same table and the flexible index plumbing and plan optimizer it provides that allows each type, regardless of how wild, to take full advantage of various index strategies and custom index bindings. Our 3 favorite custom non-built-in types we use in our workflow are
do you guys know your roots? In the late 80's the ODMG people wrote the "3rd generation database manifesto" where they expounded the benefits of using an oo language and adding durability/atomicity/isolation (I think they were not so keen on consistency). The response to that article was from Stonebraker, I call it "the empire strikes back". I have not seen a finer explanation on why you are better off taking an existing RDBMS and allowing for extension of its type system. Anyway, I can dig out the old articles, scan them and send them to you.