Don't know if this is the official way to request an enhancement, but anyway…
I see that between 1.x and 2.x the database table names were prefixed with dbmail_, presumably for namespace safety. It would be nice if there were a way to get dbmail to optionally use SQL schemas (supported by PostgreSQL (7.3+, http://www.postgresql.org/docs/8.0/static/ddl-schemas.html) and MySQL (5.0.2+)) to formally segregate the dbmail tables. This way users could (namespace-safely) include dbmail data and other data in the same database (and relate other data to dbmail data).
The schema name could be specified in dbmail.conf, [DBMAIL] section, either as a new variable (schema=…) or by appending it to db, e.g. db=my_database.my_mail_schema.
To make dbmail use the schema, db_connect() could issue a SET search_path TO my_mail_schema, or the table names could be prefixed by the schema name for all database queries (e.g. SELECT curmail_size FROM my_mail_schema.dbmail_users). The former method would seem to be the easiest, and perhaps safest.
Apr. 6 '05: The patch mentioned here: http://www.dbmail.org/dokuwiki/doku.php?id=developmentplansandideas#3 would suffice for this.
Oct. 10 '06: I think it is not a good idea to use schemas instead of table-prefixes, according to the MySQL-documentation a schema is only an alias for a database so you require to create a new database for the dbmail-tables in the idea of having dbmail-tables and other tables in the same database separated by a schema does not apply to mysql. See here: MySQL reference doc – Dennis
Feb. 25 '07: Proposed compromise: a table_prefix that can contain a dot for schema qualification (table_prefix=“schema.”)