Re: Webappication and PostgreSQL login roles

>>> I designed a Java web application. The persistence layer is a
>>> PostgreSQL database. The application needs user authentication.
>>> I think it's a good choice to implement this authentication mechanism
>>> via PostgreSQL login roles. So I can create several database login
>>> roles and set the database permissions to this login roles. This is my
>>> first project with the postgres database, so I don't know how I can
>>> validate a login from the website. Is there a best practice to do this
>>> or does PostgreSQL offers a stored procedure like
>>> 'authenticateUser(String username, String password)'?

Keep in mind that this might interact badly with very desirable features
like :

- persistent connections
(opening a postgres connection takes a lot longer than a simple SELECT,
so if you must reopen connections all the time your performance will suck)

- connection pooling
(what happens when a user gets the admin's connection out of the pool ?)

Since you use an object-relational mapper I believe it is better, and
more flexible to have your objects handle their own operations.
On a very basic level your objects can have a .isReadOnly() method which
is checked in your application before any writing takes place, for
instance.