What's in an Oracle Schema?  February 25, 2009  A fairly common
question on Oracle Q&A forums is one where the original poster
(OP) asks how to identify schemas within a database, usually
accompanied by some qualifying reason such as “my management
needs to know how many schemas we have.” Many times, a mostly
correct, but really quite misleading answer is given telling the
OP to query owner names from DBA_TABLES. When is this answer
correct? Only for those schemas (owners) who own tables. Here’s
where you can run into a misunderstanding of concepts or of the
functions/purposes a schema can support. This is analogous to a
stopped watch being correct in time at least twice a day. The
rest of the day it is wrong.  First of all, who says a schema
must (as in always) contain one or more tables? If you think
that is the always the case, you are wrong. You may have created
scores of databases back in the day, with each schema containing
tables and other objects, and of course every schema has tables
you say. But, fo