Remark: I recommend using DBD::ODBC to connect to PostgreSQL on Windows instead of DBD::PgPP (unmaintained and full of bugs, written in Pure Perl) or DBD::Pg (no Windows version on ppm & latest update on http://pgfoundry.org/frs/?group_id=1000199&release_id=1212 is for Perl 5.10 made in late 2008).

It's always the same. People using ActiveState perl and ppm, finding out the hard way that ActiveState didn't compile and pack all of CPAN. ActivePerl does not contain a C compiler, nor does it contain a linker. You are expected to buy that from Microsoft. Some other people used their resources to compile some missing modules into ppms, and provide them at various places all over the internet. Some of them contain third party code that may or may not be legally distributed in this way. The ease and beauty of CPAN is lost when you use ActivePerl.

I learned it years ago, getting more and more frustrated about that situation.

Then Strawberry Perl was released. CPAN became usable on Windows. XS modules became usable on Windows. Time could be spend for developing instead of hunting for ppm files.

Short: Get rid of ActiveStates Perl as soon as you can and use Strawberry Perl.

Regarding your special problem with PostgreSQL: DBD::Pg should compile nicely with Strawberry Perl, but you need a little bit of PostgreSQL on the Windows machine to compile the DBD. This is not a problem of DBD::Pg or PostgreSQL, it happens with every XS module that links against third party code. Most DBDs need a little bit of third party code, DBD::SQLite (comes with the required code bundled) and the "pure perl" DBDs being exceptions to that rule.

DBD::ODBC allows to connect to many databases, but that flexibility has a price tag: you add at least one extra layer of code to the communication, often slowing down your program notably. Plus, DBD::ODBC has no interface for the special features of each database. My recommendation is to use the native DBD where possible, falling back to DBD::ODBC only when a native DBD is not available or seriously broken. Typically, I use DBD::ODBC only to connect to MS SQL Server (DBD::Sybase is not the native DBD for MS SQL Server, it just happens to be able to connect to MS SQL server using an ancient protocol) and to MS Access.

Alexander