Maintaining your database logic in version control and versioning the deployed code can be a bit problematic.
Conversely, providing a standardized pgsql module through which data is updated and retrieved can help standardize access logic across multiple languages and libraries.
And I concur that database portability is a thing people like to discuss, but rarely occurs.
Portability is important for general ORM tools, less so for corporate projects (there are always exceptions).
Like any tool, needs to be used wisely.
I've worked on a project that has 10s of thousands of lines of business logic in the database and it makes perfect sense for that environment.
--Ray
While this discussion is very interesting, it is important to realize that ultimately, it is the needs and policy of the company that decides how that database is used. The primary purpose of a DBA is to install the proper security, protect the integrity of the data and maintain performance. Determining whether it is better to place business logic in the database or the application is strictly on a case by case basis.