The Oracle gateway for ODBC provides an almost seamless data integration between Oracle and other RDBMS. I won’t argue about its performance, limits, or relevance. It serves a few purposes; set it up and you’ll be able, for example, to create database links between Oracle and MySQL. After all, wouldn’t it be nice if you could run some of the following SQL statements?
select o.col1, m.col1 from oracle_tab
o, mysql_tab@mysql m where o.col1=m.col1; …