Products for connecting zope objects to RDBMS and other kinds of back-end storage.
What to look at?
If you want/need to store objects on the filesystem instead of in the ZODB, look at LocalFS (be sure to get the up-to-date version), ExtFile, ExternalFile (and maybe their plonish siblings). Each provides different functionality, so pick what you need.
If you must connect to an SQL database, you might want to look at ZMySQLDA (for MySQL?) and ZPsycopgDA (for PostgreSQL?). - there might be others (for MS SQL? ODBC?) not yet covered in this list. Note to Zope newbies: You do not need an SQL DB to work with Zope, Zope provides its own "object database" (ZODB), which works for most people.