Which files belong to which database?

Hi,

Is there a way to find out which files in $PGDATA belong
to which database?  I need that information for accounting
purposes (users are billed per Gbyte of data).  In mysql
it is very easy, because the subdirectories have the same
names as the databases.

Thanks in advance!

Regards
   Oliver

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Oliver Fromme, secnetix GmbH & Co KG, Oettingenstr. 2, 80538 München
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