From: ishikawa@cs.purdue.edu (Junko Ishikawa)
Newsgroups: comp.databases.oracle
Subject: assertion, drop schema, list tables
Date: 4 Apr 1994 00:44:57 -0500
Organization: Purdue University, West Lafayette
Lines: 32
Message-ID: <2no9gpINNpg5@aphrodite.cs.purdue.edu>
NNTP-Posting-Host: aphrodite.cs.purdue.edu
Keywords: university DB project



I am having trouble with dropping schema and enforcing constraints.
I am working on my DB class project.  Some of our requirements need to
check simple integrities.  So, I want  to create assertion to enforce the
integrities.  Yet, Oracle 7. complains the assertion statment, such as:

	create assertion <name>
	check (not exist(
			select ...
			from   ...
			where  ...));

It seems I can not create assertion.  I wuold like to know if there
is equivalent command that I can enforce the constraints.

Anothe problem I have is to drop a schema.  I created schemas without
knowing how to drop it.  Then,  after creating several small tables, I got
an error , " failed to allocate extent of size 25 in tablespace 
'CS440_TS'".  I am wondering if the schemas are the reasons why I can not
create any more tables in DB.  Anyway, I don't use the schemas.  I want
to drop them.  But, I don't know how.

The last one is to list all the tables in DB.  Although I created the
tables, I don't know how to list the tables I created.  

If there is anyone who can answer any of the questions( problems ) above,
please let me know.

e-mail:
june@sage.cc.purdue.edu

Thanks!